Blasthole Drilling.pdf

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Blasthole Drilling in Open Pit Mining

Third edition 2012 www.atlascopco.com/blastholedrills

Drill all day long

We won’t even break a sweat Your job is the first step in supplying the world with the power it needs. And to do your job, you need to keep your mines safe and productive. Atlas Copco designs and builds the blasthole drill rigs that help you reach your goals.

More drilling time!

Our multi-pass rotary blasthole drills are well known for their durability, mobility and speed. We make it possible to reduce time tramming, leveling and changing pipe so you have more time to drill.

For more information visit: www.atlascopco.com/blastholedrills Facebook.com/AtlasCopcoRotaryDrills Twitter.com/AC_RotaryDrills

Providing the right balance of bit load, rotary head performance, air flushing and depth capacity results in economical and high performance production. A variety of options like angle drilling and cold weather packages are available. But even more important is how Atlas Copco can improve your safety. Ask about the safety enhancements and automation features you can get from our Rig Control System (RCS.)

Contents Foreword     2

Foreword by Brian Fox

Talking technically   3   11  13  17  23  29  35  37  41  43  47  49  53  59  69  71  75  79  83  87  91

From gunpowder to Pit Viper Ergonomics and safety Personnel rig protection An introduction to surface mining Putting rotary drilling into perspective Automated surface blasthole drilling Taking advantage of single-pass drilling Drilling at high altitudes Drilling in Arctic conditions Tricone rotary blasthole drilling Optimizing the rotary drill string Increased productivity with DTH drilling Selecting the right DTH drilling tools Blasting in open cut metal mines Fuel saving clutch The mid-range Pit Viper 235 Development through interaction The large Pit Viper 310 series Large diameter drilling The economic case for routine bit grinding Secoroc Jazz

Case studies  93  99 101 103 105 107 109 115 117 119 123

Aitik eyes top three efficiency – Copper/Sweden Asarco’s choice: both diesel and electric – Copper/USA Reopening of Copper Mountain – Copper/Canada Radomiro Tomic prioritizes service – Copper/Chile Automation at Escondida – Copper/Chile Ambitious target at Esperanza – Copper/Chile Raising to the altitude challenge – Copper/Chile Innovation through interaction – Gold/USA Unforgiving ground – Gold/USA Community-friendly mining – Gold/Canada Drilling reliability at Veladero – Gold/Argentina

129 133 137 141 145 149 155 157 159 163 165 169 171 173

Penasquito powers up – Gold/Mexico Secoroc hammers go for gold – Gold/Turkey Advanced iron ore mining in Ukraine – Iron/Ukraine Steep wall open pit mining at Zhelezny – Iron/Russia Mining industry’s new beginnings in Mongolia – Coal/Mongolia Coal mining in eastern Australia – Coal/Australia The fuel cost killer of Queensland – Coal/Australia Boosting Siberian energy – Coal/Russia Hidden treasure beneath America's western prairie – Coal/USA Finding a perfect balance – Coal/USA Moving mountains – Coal/USA Cost busting – Coal/USA Mining in Kazakhstan – Coal & Gold/Kazakhstan Drilling for coal in Vietnam – Coal/Vietnam

Product specifications 175 179 180 211 236 239 246 250 255 256 258 260 270 273 276 280 288 295 300

Drilling methods guide Specifications guide Blasthole drill rigs Drill rig options Compressors and boosters Tricone rotary blasthole drilling Bit selection Sealed bearing When to change a bit How a rock bit drills Importance of records Air practices Rock formation & drillability Guides for best bit performance DTH hammer specifications Secoroc grinding tools Service and training Glossary of terms Where to find us

For latest updates contact your local Atlas Copco Customer Center or refer to www.atlascopco.com/blastholedrills

Produced by: Atlas Copco Drilling Solutions LLC, PO Box 462288, Garland, TX 75046, USA, Phone +1 972 496 7400. Publisher: Ulf Linder, [email protected] Editing team: Cecilia Einarsson, Diane Norwood, Elisa Davidson, Gunilla Lindberg, Justin Cocchiola, Marino Wallsten, Matthew Inge, Torbjorn Viberg, Ulf Linder. Adviser: Dustin Penn, [email protected] Contributors: Brian Fox, Clarence Zink, Bo Persson, Dustin Penn, Gunnar Nord, Jim Langford, Tyler Berens, Jon Torpy, John Stinson, Leif Larsson, Maureen Bohac, Morgan Penn, Rick Meyer, Sverker Hartwig, Ted Aikman, Tyler Berens, all [email protected] code.atlascopco.com William Hustrulid, Hans Fernberg, Kyran Casteel, Scott Ellenbecker, James Lawrence, Mark Stewart, Adriana Potts, Joseph Bradfield, Sara Schmuck. Digital copy of Atlas Copco reference edition can be downloaded at www.atlascopco.com/blastholedrills. Reproduction of individual articles only by agreement with the publisher. Layout: Rafaella Turander, ahrt informationsdesign, Örebro, Sweden, [email protected] Printed by: Executive Press, Richardson, Texas, www.executivepress.com Legal notice © Copyright 2012, Atlas Copco Drilling Solutions LLC, Garland, Texas, USA. All rights reserved.Atlas Copco is committed to comply or exceed all applicable laws, rules and regulations. Photos in this publication may show situations which complies with such laws, rules and regulations in the country where the photo has been taken but not necessarily in other parts of the world. In any case think safety first and always use proper ear, eye, head and other protection to minimize risk of personal injury. This publication, as well as specifications and equipment, is subject to change without notice. All Atlas Copco product names (including but not limited to Pit Viper, ROC, COPROD, TEAMALLOY, SmartRig, SmartROC, COP and Secoroc) are registered trademarks or trademarks of one or more Atlas Copco Group companies.

Blasthole Drilling in Open Pit Mining 1

Foreword “

Blasthole Drilling in Open Pit Mining is designed to be a comprehensive reference on the application of rotary drills in surface mining applications, plus an overview of the current product offering from Atlas Copco.



Open pit mining technology continues its evolution, as seen everywhere at MINExpo 2012 in Las Vegas. Atlas Copco prides itself in being at the forefront of blasthole drill automation with our proven Rig Control System (RCS). We have many of the building blocks in place for autonomous drilling, and extensive plans to tie everything together for a safe, reliable solution that integrates seamlessly into the mines communications infrastructure. We will stay on target and execute these plans. We will also stay on target with our efforts to continually improve the safety of our machines. Safety First is our approach within our factory and engineering teams. One such example is our project to fit a multitude of local Australian options (known as J4) at our facility in Texas; this is proving very successful. These options are designed to yield improved operation and maintenance of the machines, with the goal of further improving safety performance. We anticipate that more markets will adopt these options in the future. Despite economic uncertainty in the world as this Third Edition is released, we find the mining industry running at a high level. We are proud to be a part of it, and are working hard to introduce new products such as the Pit Viper 311 and continually improve our sales and support capabilities worldwide. Our singular focus is blasthole drills for open pit mining. It’s all we do. We hope you enjoy this third edition.

Brian Fox Vice President, Marketing Atlas Copco Drilling Solutions LLC [email protected]

2

Blasthole Drilling in Open Pit Mining

Talking Technically

From gunpowder to Pit Viper Drilling and blasting The rotary blasthole drilling rig was a long time coming. Gunpowder was invented in China about 1000 A.D. But in Europe at least it took another 500 years or more before miners started to use it for blasting and a further three centuries for the introduction of mechanized drilling in surface mines. Mobile blasthole drilling rigs have been in use for only some sixty years.

Gunpowder The application of blasting agents apparently began in Hungarian mines sometime during the sixteenth century. To make better use of the explosive force, miners started to place the powder in holes and it is certain that drilling and blasting were used in several German and Scandinavian mines early in the seventeenth century, for instance at the Nasafjäll silver mine in Lappland in 1635, and in 1644 at the Röros mine in Norway. One-man drilling with the help of a drill steel and sledgehammer was the established technology used in the

Drilling with sledgehammer was the established method before the development of the rock drill.

The Pit Viper is designed for production drilling of large holes in hard rock conditions.

eighteenth century. This physically demanding technique evolved only slowly but, despite the mechanization of other industries, remained in quite widespread use until well into the twentieth century. However, powered drills did start to mount a challenge in the 1800’s, the competition in the USA being symbolized by John Henry who in 1870 hammered through 14 feet in 35 minutes while the steam drill only completed nine feet. The first patented rock drilling machine was a steam driven percussion drill invented by J. J. Couch in Philadelphia in 1849 but it may have been preceded by a machine manufactured by the Scottish engineer James Nasmyth ten years earlier. This patent spurred a period of rapid development, accelerated in the 1860s by Nobel’s inventions of the blasting cap and safe dynamite explosives. From 1850 to 1875 some 110 rock drill patents were granted to American inventors and seven for drill carriers while 86 patents were issued in Europe during this period.

In 1851 James Fowle, who had worked with Couch, patented a rock drill that could be powered by steam or compressed air and could rotate the drill steel by means of a ratchet wheel controlled by the piston's back-andforth movement. In the 1860’s large scale rock drilling machines were built for tunnelling by engineers in Europe and the United States. One of the most successful of these early rock drills was the second refined version of the Burleigh rock drill, which was put into service in October 1866 at the Hoosac tunnel in Massachusetts. The performance at this tunnel project showed that rock drill development had taken the step from an experimental product to a proven and rather reliable technology. In 1871 the American inventor Simon Ingersoll patented a steam powered rock drill, later to be operated on compressed air. Ingersoll formed the Ingersoll Rock Drill Company in the same year. During the following year Ingersoll purchased the Fowle-Burleigh patents and also merged with the Burleigh company.

Blasthole Drilling in Open Pit Mining 3

Talking Technically

In 1871, a number of patents were issued to the inventor Simon Ingersoll, who started the Ingersoll Rock Drill Company The machine produced by Ingersoll was at this time regarded as the best rock drill yet produced, and it was followed in the mid 1880s by another success, the famous “Ingersoll Eclipse” machine.

The new compact rock drill launched by Ingersoll was a simple and strong design with few moving parts. The designers had kept in view the tough conditions in which the rock drill had to work, and the contemporary technical opinion regarded his new rock drill as the best yet available on the market. During the years to come Ingersoll bought out many small firms and expanded his company. The Ingersoll Rand name came into use in 1905 through the combination of Ingersoll-Sergeant Drill Company and Rand Drill Company. The AB Atlas enterprise had been founded in February 1873 at a time when the Swedish railway net was being rapidly expanded. Three years later, now with 700 employees and the Stockholm shops completed, AB Atlas had delivered more than 600 railway wagons. Diminishing demand from the railroad sector, combined with years of losses, led to a reconstruction in 1890. During the years to follow new product lines were added, including compressed air tools, compressors, diesel engines and the first Atlas rock drill which was launched in 1905.

The Ingersoll rockdrill was a simple and strong design with few moving parts.

it was very heavy for manual use. Immediately and for the next 25 years Atlas focused on light weight hand rotated drills like the Cyclop, Rex, and Bob. The real Atlas winner among lightweight hand-held rock drills was the RH 65 from the year 1932. This machine had more efficient shank and chuck designs for better steel guidance and longer shank life. Used with the new pusher leg feed system developed in the 1930s, the RH 65 was the most important element in what was later to become known as the "Swedish method" of underground drilling. In the United States Ingersoll-Rand expanded into pneumatic tools in 1907 by acquiring the Imperial Pneumatic Tool Company of Athens, Pennsylvania.

In 1909 the company bought the A.S. Cameron Steam Pump Works and entered the industrial pump business. Ingersoll Rand also acquired the J. George Leyner Engineering Works Company. This firm had developed a small, pneumatic hammer that could be operated by one man. This “Jackhamer” introduced in 1912 became a popular item, and the company progressively developed the design as well as supplying compressors to the expanding construction and mining industries in North and South America

Rock drilling tools The parallel improvement of drill steel quality had started during the 1890s

Further development The design of the first Atlas rock drill featured an advanced rifle bar rotation but with a weight of 280 kg (617 lb) 4

The first drill made by Atlas "pneumatic rock drill No. 16" had a weight of 280 kg (617 lb) and was heavy and difficult to handle - at least two men were needed to move it.

Blasthole Drilling in Open Pit Mining

Talking Technically

with development of heat treated drill steel that could better resist deformation. But sharpening the tips required extensive haulage of tons of drill steel between drilling sites and the work shops. The detachable drill bit was developed in 1918 by A L Hawkesworth, a foreman at the Anaconda copper mine in Butte, Montana. The first versions used a dovetail joint to the drill steel while later versions were threaded or tapered. The rods were retained at the workings and used with new or re-forged bits. In Europe during the German collapse in 1918 a team was formed at the Osram lamp factory to develop cemented tungsten carbide as a substitute for industrial diamonds. In 1926 the first cemented tungsten carbide became available as a “magical” machine tool for turning and milling operations. Early tests were made in 1928 trying to use tungsten carbide bits for rock drilling in German mines and before World War II promising results were obtained. By this time the research team had scattered and some members had been forced to leave the country. One of these, Hans Herman Wolff, found refuge in Sweden where he worked at the Luma lamp factory. Dr Wolff manufactured a number of bits according to designs provided by Erik Ryd at Atlas. The bits were tested in the Atlas test mine. In 1942 Atlas, Sandvik and Fagersta signed a cooperative agreement and it was not until 1945, after a long improvement process, that the new cemented tungsten carbide drill bits were as economical to use as conventional steel bits. The post-war years saw Atlas achieve further major advances. In 1948 the company introduced an RH 65 upgrade, the RH 656, which was designed to use the new cemented carbide tipped drillsteels. The superior performance of the “Light Swedish Method” was exploited worldwide and culminated in 1962 with the completion of the Mont Blanc tunnel. With development of highly mechanized drill rigs and with the introduction in 1973 of the COP 1038 hydraulic top hammer drill Atlas Copco laid the foundation to become a world leader in top hammer drilling technology. (See article from wagon drill to SmartRig, Surface drilling, Fifth Edition 2012).

The US patent for a dual roller cone bit was issued to Howard Hughes Sr. in 1909.

Rotary bits Rotary drilling with drag bits was the common method used in oil drilling. These bits were suitable when drilling in soft formations like sand or clay but not in rock. The solution for drilling large diameter holes in rock was by using rotary crushing technology instead of trying to cut hard rock with drag bits. The roller cone bit was developed by Hughes and Sharp, and the US patent for a dual roller cone bit was issued to Howard Hughes Sr. in 1909. This new type of bit had two interlocking wheels with steel teeth, and penetrated the rock by crushing and chipping. The success of the new bit led to the founding of the SharpHughes Tool Company, and after Sharp's death in 1912 the name was changed to Hughes Tool Company. The company continued development of the roller cone bit and in 1933 two Hughes engineers invented the tricone bit. This bit had three conical rollers equipped with steel teeth. Drilling was accomplished by transferring a pulldown force to drive the teeth into the hole bottom. The three roller cones turned as the drill string was rotated, and the teeth crushed and spalled the rock. While tophammer drills could be used for small blast holes in rock, this method was not suitable for large hole diameters; for these rotary drills were

the best alternative. However, as drillers sought to use the rotary system for progressively harder rock formations so the feed force (pulldown) available had to be increased. Roller cones with long steel teeth were used in softer formations for gouging the formation while roller cones with shorter teeth were used for crushing and spalling harder formations.

The Secoroc Omega sealed bearing tricone bits are now regarded as the ultimate blasthole bit solution.

A parallel development of the tricone bits made it possible to use these high loads on bits. To extend the life of the bits in hard and abrasive rock the steel teeth were replaced by cemented tungsten carbide inserts. Tungsten carbide inserts have significantly increased the number of blast holes that the roller cone bits are able to drill.

Blasthole Drilling in Open Pit Mining 5

Talking Technically

Big picture; Airpowered DM-3 with a DRD-2 Rotary head from the late 1950's. Inset; Tractor mounted Drillmaster, air powered with a DRD Rotary Head from the early 1950's.

Improvements in materials have continued to increase the life of the bearings so the cutting structures can be fully utilized. While the geometry of the roller cone bit is much the same as the original bit patented in 1933, the material and technology currently utilized is cutting edge.

Downhole drilling technology Meanwhile, manual lightweight pneumatic drills had also underpinned the expansion of bench mining in open cut mines and quarries. But in the 1930’s

downhole drills (DHDs ) were introduced for drilling deeper holes. The main initial development of this technology took place in Belgium and the United States. Atlas designed a downhole unit in the mid-thirties that was used with good results in two Swedish limestone quarries until the 1950s but the company then ceased further DHD development, only re-entering the market in 1969 with the COP 4 and COP 6 down-the-hole hammers. Followed by the valve less COP 32 42,52 and 62 from 1978, where still COP32 is in use. In 1955 Ingersoll-Rand introduced a new downhole drill design and started

The Quarrymaster from 1948 was equipped with a huge 8" bore drifter.

6

to establish downhole drilling on a truly commercial basis. The Tandematic, which at the time was claimed to provide the highest drilling speed ever attained by a downhole drill, was supplied in two standard sizes – the DHD 275 for 4¾* inch and 5 inch holes and the DHD 1060 for 6 and 6½ inch . This later enabled the company to build drill rigs adapted to be used either for rotary drilling or with downhole hammers. The main difference is that downhole drilling requires more air, and consequently these drill rigs had to be equipped with a larger capacity compressor and a more powerful diesel or electric engine. Downhole drill technology went through rapid change in 1960’s and 70’s. In fairly rapid succession I-R developed the DHD 325 ( their first 6" hammer), DHD 325A, DHD 16, DHD 1060, DHD 1060 A and B models, DHD 360 (all 6" drills) and corresponding larger and smaller models, up to the current line of DHD’s. Probably the most significant change in DHD technology was the advent of the valveless DHD. Drill efficiency and life dramatically improved with the elimination of the flapper valve. During the 90’s the QL series of hammers came with the unique QL (Quantum Leap) design , a still valid patent. This features makes it possible to have the piston stroke pressurized 80% of it’s distance compared with 50% for other hammer design. The QL feature is also used in the TD hammers series for deep hole drilling. Of course higher pressure and volume air from the air compressor advancements produced the performance one sees today. Re-entry to the downhole drill market at 6 bar** in 1969 also enabled Atlas Copco to take advantage of improved air compressors and develop more and more powerful downhole hammers, reaching 18 bar in the early 1980s and more recently 25 bar and 30 bar in the larger current hammer sizes. In the early 90’s COP44, 54 and 64 where introduced by Secoroc. A series of high performing hammers operating at high air pressure. They were unbeaten in blast hole drilling applications until replaced by the COP Gold series in the beginning of 2000’nds. *1 inch = 25.4 mm, **1 bar = 14.5 psi

Blasthole Drilling in Open Pit Mining

Talking Technically

Secoroc COP64 Gold downhole hammer.

Drill rigs The mobilization of rotary and downhole drills was linked to significant post-war changes in rotary drilling technology. Up until then rotary drilling had been used in water well drilling and surface mining using fluid circulation to clean cuttings from the hole. Coal mines were using rotary drilling in soft overburden, removing the cuttings with augers. In the late 1940’s it was realized that air was an effective flushing medium with considerable advantages over water, doing a better cleaning job, protecting the bits and eliminating the difficulties of supplying water. Experience also proved that air flushing improved the penetration rate of rolling cutter bits such as tricone bits and extended their life. By using efficient air flushing to keep the bottom of the drill hole free from cuttings the rock breaking process became more efficient. In 1948, Ingersoll-Rand entered the large-diameter blast hole market by launching the Quarrymaster. It really was not a rotary drill, but a large self propelled mounting in the 40,000 lb* weight range, designed with on board air and a long drill tower to drill 6 inch to 8 inch diameter holes for mining and quarry applications. The original Quarrymasters were equipped with a huge 8" bore drifter, know as the QD8. This was a piston drill with the drill steel attached directly to the drifter piston. The blow frequency was in the range of 200-300 blows per minute. The drifter used a large rifle bar rotation system. Achieving decent wear life between the rifle bar and rifle nut was sometimes a problem in tight ground. This was a single pass drill system, hole depth was limited by the tower length. The steel system was a heavy wall tubular product, in the range of 4"

OD, and was extremely heavy. Since there was no steel change, the weight didn’t seem to be much of an issue. Quarrymasters were used in some large iron mines in Canada and the Atlantic City Iron Ore Mine in Wyoming. Numerous Quarrymasters were used in the rock excavation for the St Lawrence Seaway in Canada. In the same year also Atlas introduced its first mobile rubber tired drill wagons for top hammer drilling, but these were not equipped with any tramming machinery and were intended for considerably smaller hole diameters. I-R development work with downhole drills in the early 1950’s brought about changes to the drill mounting business. First, the Quarrymaster was equipped with the newly developed QRD rotary head, and this along with the new DHD 325 down hole drill, made for a productive but heavy and bulky package. The Drillmaster design, a somewhat smaller rotary drill, was introduced about 1955. It produced the same performance as the Quarrymaster in a smaller and less costly package. Upgraded versions of the Drillmaster, the DM-1, DM-2 and DM-3 followed in quick succession. Originally equipped with sliding vane air compressors up to 900 cfm**, all were updated to the screw compressor design. The Drillmaster line was equipped with the DRD and later DRD 2 rotary head to provide drill string rotation. As with the QRD rotary head the DRD was powered by a vane air motor and several steps of gear reduction. All of these drills only used hydraulic power, from an engine driven hydraulic pump off the cam shaft, to operate the jacks, tower raising cylinders, break-out wrench, and dust collector drive motor. Neither rotary head was *1 lb = 0.45 kg, **100 cfm = 42.2 l/s

very useful in supplying straight rotary power for tricone bits, hence the future development of the T-4 and DM-4 with hydraulic powered rotary head for straight rotary drilling. I-R’s first truck drill was called the Trucm package. The drill frame package was mounted on a customer provided truck, often a used Mack truck. However, none of the standard truck designs proved very successful. The normal channel truck frames were not sturdy enough, resulting in many cracked and broken truck frames. I-R’s answer to this problem was to join hands with Crane Carrier Corp of Tulsa, OK, and mount the drill components and tower directly on an I-beam chassis frame, often used for mounting construction cranes. This product became the TRUCM-3 and the same style mounting carried over to the T-4 and T4W introduced in 1968. A major new stimulus for blasthole drilling rig development generally was the introduction in the 1950’s of millisecond delay blasting. This allowed blasters to design multi-hole large volume blasts that could be used for mass production techniques in open

The truck mounted T4BH was introduced in 1968.

Blasthole Drilling in Open Pit Mining 7

Talking Technically

The DM50 could use bit loads up to 50,000 lbf and was launched in 1970.

cut drill and blast mines. In turn this required the introduction of large, mobile drilling rigs able to drill large diameter holes using tricone bits, as well as the formulation of cheap bulk mining explosives based on ammonium nitrate and nitro-glycerine. These and other developments helped the mining industry to keep the costs of bench drilling substantially unchanged during the 1950s and 1960s, despite increasing wage costs. The Quarrymaster and TRUCM machines were made progressively more self-contained through the 1950s. By the end of the decade the air supply was up to 10 bar and the marketing slogan “Pressure is Productivity” was promoted. The drill rigs and rock drills were sold together to maximize revenue but this did encourage other manufacturers to build competing rock drills.

Hydraulics technology adds to drillers options The similarities between the air requirements of rotary and downhole drilling made the design of rigs able to do both an economically attractive proposition. In 1965-66 Ingersoll-Rand started work on the switch to hydraulic powered rotation for rotary and downhole drilling, launching first the truckmounted T4W for water well drilling in 1968. In the same year this rig was modified to make a truck-mounted blasthole rig with a 5-rod carousel, the Drillmaster T4BH, which could drill holes of up to 7⅞ inch diameter and was successfully offered for coal mine drilling throughout the 1970s. 8

The designers also used the power unit, tower and other components to create the crawler-mounted Drillmaster DM4 blasthole drilling rig. This machine was designed from the ground up for both rotary and downhole drilling. A 36 ft* high tower incorporated a hydraulically indexed carousel housing seven 25 ft rods. The rotary head featured an axial piston hydraulic motor and single-reduction worm gear for rotation, providing 5.6 kNm of torque and rotation speeds from 0 – 100 rpm. There was a choice of diesel engine or electric motor for the spring mounted f loating power pack and a range of diesel or electric compressors, enabling use of either rotary or downhole drilling with the company’s DHD-15, -16 or -17 downhole drills. The excavator style crawler undercarriage had tracks with 22 inch triple bar grousers driven by hydraulic motor through a planetary gear drive and chain reduction. In the marketplace the DM4 competed with the more powerful electric top drive blasthole drilling rigs. The late 1960s and 1970s saw heavy takeup of the DM4 rig by the Appalachian coal mines in the United States. And the combination of patented rig, drill and drill rod technology was very profitable for Ingersoll-Rand. The use of hydraulic power for rotation and non-drilling functions meant that more air could be made available for rotary and, especially, for downhole drilling. This engendered an “air race” in the late 1960s and 1970s. The independent downhole drill manufacturers were able to build machines that could drill at 130 ft/hour in the 6 – 8 inch diameter hole range – faster than a rotary drill could achieve in this hole size range, particularly when drilling in harder rock types. The development of screw compressors to supply air for drilling rigs at up to 20.6 bar led to the 1970s introduction of an airend to supply both low pressure and high pressure air. These units were used in portable air compressors and also onboard drilling rigs, where they enabled downhole drills to outper*1 ft = 0.304 m **1,000 lbf = 4.44 kN = 453 kilogram-force

Rotary table and Kelly bar concept.

form rotary drills in the 6 - 8½ inch hole sizes in hard rock mines. However, rotary drills were still better for rock compressive strengths up to medium hard limestone. The higher pressures were also very beneficial for water well drilling, in which air pressure must be sufficient to evacuate the ground water pressure from the hole while drilling.

Expansion of the Drillmaster range Significant corporate developments and one major product launch impacted the Ingersoll-Rand drilling business in the mid-1970s. Firstly, in 1973 the company acquired DAMCO (Drill And Manufacturing Company) in Dallas, Texas, who built mechanically driven pre-split drilling machines for quarrying and light coal stripping. These expanded the Drillmaster range down to the 20,000 lbf* bit weight class. The rigs also used the rotary table drive and kelly bar concept, which lightened the tower structure sufficiently to accommodate rod long enough to drill 40 – 50ft holes in a single pass if required. IngersollRand added their own compressors to create the DM20, DM25, DM25-SP (single-pass), DM35 and DM35-SP rotary rig models. Then, in 1975, the company bought the Sanderson Cyclone Drill Company in Ohio, USA, adding 12 models designed for the water well market. The next extension of the size class range came with the launch of the Drillmaster DM50 with 50,000 lbf of weight on the bit. In this machine the Blasthole Drilling in Open Pit Mining

Talking Technically

diesel engine drove the hydraulic power pack from one end of the crankshaft and the compressor was directly coupled to the other. This concept was also used on the next two drills to be launched. The first one was a new crawler mounted rig for rotary or downhole drilling, the DM45 with 45,000lbf weight on bit. This was followed by a conceptually similar top drive rotary or DHD model, the DM30 and a specialized rotary table variant, the DM-35I, which was introduced in the 1980s for drilling underwater in phosphate mines. It featured a dual kelly system that allowed explosives to be charged through the annulus between the outer and inner kelly. The inner kelly would then be removed for blasting. Later the DM 40SPi was developed for drilling and shooting deeper holes.

Development of large blasthole drills Towards the end of the seventies, the company started designing drill rigs more specifically aimed at the base metal mining market, using power pack concepts developed for deephole drilling. So far, neither air-powered nor hydraulic drive rotary nor downhole drills had challenged the electric motor top drive rotary rigs manufactured in the United States for the 12 – 15 inch diameter hole market. These machines by now had very high weights on bit in the range 100,000 – 120,000 lbf, partly due to the weight of the electric motor for the rotary head, but were not suitable for live tower operation. Ingersoll-Rand’s first response was in 1979 with the development of the Drillmaster DM70, able to drill 10 inch diameter holes in metal mines and up to 12½ inch holes at coal mines using 8.6 bar air for rotary drilling. And in 1979 the company launched the DM-H (Drillmaster – Heavy), the first truly modern large blasthole drilling rig to be used for low pressure rotary drilling of 9 7/8 12 1/8 inch holes with bit loads up to 90,000 lbf. The DM-H used hydraulics for both drilling and non-drilling functions and featured a hydraulic propel excavator type undercarriage with easily replaceable grouser pads and in-line

components on the deck. It was equipped with a rotary screw compressor and a “live” tower with patented angle drilling system. The tower pivot point was flush to the drill deck and within the dust curtain, reducing the length of unsupported drill rod. It was an all-purpose machine, with a singlepass version added in the mid-1980's. The machine has been upgraded over the years although replaced by the Pit Viper 351 for hard rock applications. At much the same time the company started to offer electric powered versions of the DM 45 and other models if customers wanted them, for instance for use in open pits where the other key equipment was electric powered. However, although these machines had electric motor power packs they retained the hydraulic rotation system. The first electric drill rig was the DM7B delivered to Clarksburg in 1977, followed a year later by the DM100 delivered to Rock Springs. After recovery from the recession of the early 1980’s, Ingersoll-Rand launched a medium range Drillmaster, the DM-M designed for rotary drilling of 9 7/8 inch holes with bit loads up to 60,000 lbf. Three of the first four DM-M's went into operation at Peabody Energy's new Nor th Antelope & Rochelle Mine in the Wyoming Powder River Basin, now one of the two largest coal mines in the world. Now, over 25 years later, the prototype DM-M is still in operation. The machine featured a carriage feed system with wire rope cables, resulting in a lighter tower and lower center of gravity. In 1989 this model was upgraded to the DM-M2 on which maximum bit load was increased to 75,000 lbf and the hole size capability extended up to 10 5/8 inch. Stability was improved as well. In 1990-91 the company introduced the DML for multi-pass drilling to 180 ft hole depth. This new model could drill from 6 to 9 7/8 inch (200 – 250 mm) diameter holes in rotary mode, and 6 – 8 7 / inch using a downhole hammer. 8 Following a development project based on a customer consultation exercise the DM-M3 was launched at MINExpo 1992. Designed primarily for deep drilling of overburden for cast blasting

The DM-H, launched in 1979, could be used with bit loads up to 90,000 lbf (400 kN).

The DM-M3 launched in 1992 is used for multipass drilling in coal mining.

Milestones in development Year

Model

Load on bit

1948

Quarrymaster drifter

1955

DM3

30,000 lbf

1968

T4BH

30,000 lbf

1969

DM4

40,000 lbf

1970

DM50

50,000 lbf

1979

DM-H

90,000 lbf

1983

DM-M

60,000 lbf

1990

DML

60,000 lbf

1992

DM-M3

90,000 lbf

2000

PV-351

125,000 lbf

2004

PV-270

75,000 lbf

2008

PV-235

65,000 lbf

2012

PV-311

110,000 lbf

Blasthole Drilling in Open Pit Mining 9

Talking Technically

The first Pit Viper 351 was launched in 2000 and used at the Morenci copper mine in Arizona.

in large coal mines, the first production DM-M3 went into operation in 1993 at Arch Coal's Black Thunder Mine, one of the largest coal mines in the world. For this new model, the designers raised bit load to 90,000 lbf and the hole diameter range up to 12 ¼ inch while a new patented cable feed allowed the use of 40 ft long drill rods.

The launch of the Pit Viper Although difficult market conditions restricted investment in the mid-1990’s, during 1997 the company started work on a new generation blasthole drilling rig design. To differentiate this new range from the Drillmaster series, which initially was designed for drilling large holes in coal mining and soft rock, this new series was - from the very beginning - specified and designed for production drilling of large holes in hard rock conditions. The first one out was the Pit Viper 351, which was successfully launched at MINExpo 2000. Weighing 170 tonnes, measuring 53 feet long, and equipped with a CAN-bus control system with seven on-board computers, the new Pit Viper 351 was at that time the largest and most advanced drill rig of its kind. The advanced control system allowed the drill pattern to be transmitted to the drill rig via a radio network, and it also featured production monitoring, 10

The Pit Viper 235 was launched at MINExpo 2008.

rock recognition and a GPS navigation system. A few months after the Minexpo show, in April 2001, the PV-351 was put to work at the Morenci copper mine in Arizona for final testing and evaluation. The mine had a fleet of 16 drill rigs from a variety of manufacturers, so in addition to the new rig being used for drilling in the hard igneous rock conditions, this was an excellent opportunity for benchmarking the PV-351 with the other brands. The application required 12 ¼ inch diameter single pass drilling of 57 ft deep blastholes using up to 90,000 lbf weight on bit (of the 125,000 lbf capacity). The test was successful: the PV-351 drilled some 2.2 million feet by August 2004 at a recorded average rate of 60,000 feet per month and in some months even more than 80,000 feet per month. Later the same year the multi-pass Pit Viper 275 was launched at MINExpo 2004. Based on the experience from the PV-351, combined with customer consultations, a project had been initiated for development of the PV-270 series. These drills were specified for a 75,000 lbf bit load capacity and were featured a similar cable feed system and automatic cable tensioning to that on the larger PV-351. The multipass version PV-275 with a 195ft depth capacity was delivered for a test in December 2003 at Peabody's Kayenta coal mine in Arizona where it was used for cast blast drilling

The new Pit Viper 311.

for removal of the overburden. This first machine is still in use there and, as a result of the good performance, the mine decided to invest in several additional units. One of these was prepared for quick change between a multi-pass and a single-pass tower as an option to be adapted for different applications at the mine. The first mine to use the single pass version, the PV-271, was the Barrick Goldstrike mine near Elko, Nevada. Since the PV-271 arrived at the mine in April 2004 it has been problem-free, and holds an impressive track record with an average penetration rate of 199 ft per hour. The long component life and also the automatic tensioning adjustments for the cables are much appreciated by the mine. Following this tradition of product launches in Las Vegas – the PV-235 was introduced in 2008 followed by the PV-311 at MINExpo in 2012. These new drill rigs are automation ready, featuring the RCS (Rig Control System) as standard.

Acknowledgements Editors: Kyran Casteel and Ulf Linder Contributions: Guy Coyne, Ron Buell, Kenneth Moffitt, Brian Fox, John Stinson, Dustin Penn, Gunnar Nord, Sverker Hartwig, Jim Langford, Diane Norwood, Darwin Hollar, Ewald Kurt.

Blasthole Drilling in Open Pit Mining

Talking Technically

Ergonomics and safety Machine developments in a new decade Ergonomics today has taken on a broader meaning with the advent of safer work rules, higher work efficiencies and superior design tools. Today engineers can study and design machines that are efficient to operate, maintain, build and transport. Engineering tools, new materials, improved industry standards and new technology allow a designer to model a machine and actually simulate operation under safer operating conditions.   During this decade not much has changed with the technical performance of drilling as cutting structures remain the same. Rather the design emphasis has been on efficiency, fewer accidents and ease of operation. Globalization of mining to a higher level is also driving changes. The HIV epidemic in Africa is reducing the workforce at an unheard of rate. New deposits in arctic regions require a new emphasis. This article highlights the advances Atlas Copco Drilling Solutions engineers have made to meet these new challenges.

Ergonomics and safety for operators Today much has changed with regard to operators, machines and machine interfaces. Twenty years ago the industry took a macro view of an operator’s ability to complete a shift without tiring or having an accident. Today designers work to a micro requirement; neither a hand nor a finger must be injured over a 30-year career doing the same function. In the past the requirements were for gauges and levers to be properly placed to avoid human strain during the work shift. Now engineers analyze site paths, a process of ensuring that natural hand motions are used to operate equipment. The drive for safety and efficiency are integrated.

Reference dust management improvement.

Not only does the manufacturer look at drilling as the sole function of an operator. A multi-skilled operator may also manage drilling consumables, complete basic maintenance and report details of bench conditions. These new roles also must be designed into the machine interfaces. Also with regard to improved ergonomics and safety, Drilling Solutions engineers work to design systems that eliminate or reduce the hazards. In the late 1990s when the United States Mining and Safety Administration imposed stricter silica exposure limits for operators, engineers found that improved air quality could not be achieved without removing the concentration levels in certain applications. The drive then became to manage the dust rather than improve air quality through expensive filtration. The goal of Drilling Solutions is to allow the operator to do what comes naturally and to create a work environment that provides superior comfort and safety.

Operator cabins and machine interfaces A rotary drill is recognized as one of two pieces of surface mining equipment that sits and works in its waste, heat and dust. The other piece is the shovel or excavator. The operator’s cabin, or cab, is the device used to protect the operator, a design factor not seriously considered as late as 1995. Nearly everyone would agree today’s automobiles are safer, quieter, offer a smoother drive and are very user friendly. The automobile is becoming the acceptable standard in industry when looking at operator cabins. The visual look of an operator cab has also become a design criteria, as personnel equate past operator cabs with a metal box that induces high fatigue. An automotive’s structure and safety systems keep passengers safe. Likewise today’s drills are engineered to protect an operator against hazards that once injured or killed operators.

Blasthole Drilling in Open Pit Mining 11

Talking Technically

allows an operator to watch the areas where visibility is restricted. The combined effect is to give operators a full view from the operator’s chair. The operator chair and flooring play active roles in reducing drilling vibrations, which add to operator fatigue. Now an operator’s chair is often referred to as an operator’s pod, and is adjustable to fit a variety of shapes, sizes and weights. All machine interfaces are now within the operator’s reach. Technology can also play a role in protecting the operator from dangerous work conditions. Drilling Solutions engineers, working with suppliers, are creating a system that allows limits of operation to be defined and to give an operator feedback when an unsafe condition exists. As drilling conditions change within the pit, the machine can be easily reprogrammed to fit the new situation. The result of this combined effort is to deliver a safe, comfortable work environment that is suited for the long shifts required in surface mining.

Operator survived rock fall.

Maintenance ergonomics

The image shows a digital leveling device on which the background can change colors, sound an alarm or remove power when an unsafe angle of operation is experienced.

Comfort combined with ease of operation in one package.

The image shows digital readouts of weight on bit, rotation speed, torque and rate of penetration. It also can be programmed to give an operator visual feedback.

The image above shows a rock fall that the operator survived without injury. Using proper de sign techniques and better materials. Atlas Copco engineers have delivered an operator cab that reduces interior noise levels significantly below the industry benchmark 12

of 80 dBA. For example, the Pit Viper 351 with 1500 hp was measured below 70 dBA when drilling. Like automotive climate control systems are developed to maintain operator comfort more efficiently, today’s systems direct the cooling effort on the operator. The systems are also used to defrost windows in cold weather climates just as automobiles do. Drilling Solutions engineers also are working to advance the cleanliness of the air the operator breathes. Engineers can use computer models to quickly improve line of site. Cabs now feature more window space, which improves visibility, due to glass and insulation technology. Camera technology

Nearly unheard of a decade ago, industry standards now require safe, routine and easy access to all maintenance points. In the 1990s the Australian New South Wales MDG-15 Act gave guidelines for maintenance ergonomics that have become the accepted standard in industry today, and these standards, in addition to factors such as fatigue and safety, drive the machine design effort. For example, Australian studies showed a very high incident rate for personnel getting on and off machines. These results drove the international market to look at alternatives. As a result, placement of key maintenance points could only be in a zone from waist to shoulders, based on measurements for 90 percent of the population. Until fairly recently, operator comfort and safety were only afterthoughts – if they were considered at all. Now, what was once “out of sight, out of mind,” is a critical requirement at the forefront of design innovation.

John Stinson

Blasthole Drilling in Open Pit Mining

Talking Technically

Personnel rig protection Built-in safety features For drillers, the safest place to be is the cabin of the drill rig. Our equipment has many builtin features and options that help to increase operator safety such as ROPS and FOPS protection. Moreover today’s cabins are all designed with smooth edges and without protruding components that could conceivably injure an operator who omits to wear a hardhat. But the fact is, the moment the operator steps outside, he or she is immediately exposed to dangers. Over the years, technological advances have done a great deal to reduce the number of accidents and injuries. Atlas Copco is committed to this task and will continue to identify risks and improve safety through our product design.

Mining safety Since the implementation of the Mining Safety and Health Act of 1977, a lot has changed in the past 35 years. More specifically, a lot of lives have changed or been saved. Safety is the obligation of every single individual in every single step of the entire mining process. As taught in the MSHA training class “SLAM Risks” (Stop Look Analyze and Manage) helps us diminish workplace risks. SLAM was initiated to focus the mining industry on the human factors in accident prevention. At Drilling Solutions, risk assessments and design simulations are involved in mitigating risks to the operator and maintenance personnel. We should constantly be assessing our surrounding environment and risks that might be involved. It is something that we should consider in every action we take on a daily basis, from climbing off the machine, to walking out through the parking lot, to driving home that evening, to walking in that front door; safe and sound and fully intact.

The safest place to be is the cabin of the drill rig.

In order to facilitate what we should be doing on a daily basis versus what we actually do, this is a niche where we as the OEM are able to further develop safety into our products. We at Atlas Copco Drilling Solutions have spent the past year researching different scenarios and situations to find areas that can further enhance the safety of performing a specific function or task. We have conducted open-floor meetings with major mining corporations, spent time on a wide-range of different mining sites, and coordinated with various teams world wide in order to fully understand develop, and offer you a multitude of Personnel Rig Protection opportunities for your machines. Our ultimate aim is to lead the industry by changing equipment designs to minimize the risk to all parties involved in the mining process.

Tower access restraint system This option provides the mine with a dedicated resource providing a safe

means of conducting maintenance in our towers. The Tower Access Restraint System meets OSHA Standards 1926 and 1910, as well as Australian and New Zealand Standards 1891.2:2001. Drilling Solutions engineers have designed a set of stairs for access to the Tower while in the horizontal position. Each step is made of sturdy steel grating. The Stairway also consists of a signed gate at the bottom, as well as the top of the stairs in order to prevent accidental entry. There is a continuous handrail that goes up both sides of the stairway and then a spacious work platform once you reach the top. Once you have reached the top and you are ready to enter the tower to perform maintenance, you open the gate, clip onto each of the shuttles that are attached to two stainless steel cables that run the length of the Tower. The cables are permanently anchored to the Tower cords and include a shuttle on each side on which to hook the harness. These shuttles are an integral part of the structure and include a double-locking mechanism for safety

Blasthole Drilling in Open Pit Mining 13

Talking Technically

PV-270 tower access stairs. (Part of tower fall restraint system)

Tower fall restraint system with infill.

purposes and are specially designed to withstand the vigors of a mining environment. They also allow the operator full access to the Tower, as well as being able to smoothly move over transition pieces without the hazardous practice of having to unhook from the cable, allowing the individual to keep their hands free for tools and the task at hand. In addition to the Tower Access Restraint System, the bottom of the Tower is also filled with fiberglass grate decking. This is a continuous slip-resistant and sturdy surface for the individual to stand on while performing their duties. The final result of combining the above components is a safe and secure tool to utilize during regular Tower service intervals. In addition, this system provides improved safety and mobility for mine personnel.

Access and egress

Hydraulic ladder option.

PV-230 standard ladder option.

PV-230 spring assisted ladder option.

14

A lot of emphasis and design hours went into the multiple options we now provide for getting on and off the machine, always keeping ease and safety in mind. Atlas Copco now provides a number of different means to access the deck and cab on the cab side of the machine. These include your Standard Ladder, a Hydraulic Ramp, a Hydraulic Ladder, Hydraulic Stairs, and emergency ladders. Each individual step on the above ladders is comprised of either sturdy, slip-resistant steel or fiberglass grating. One more added benefit to some of the ladders mentioned is the safety interlock that is built into the RCS control system. This interlock will not allow the rig to move while the ladder is in the down position. Some of the above options are obviously more intricate than the Standard Ladder, but they do provide a more natural means of accessing the machine. They can allow the operator or maintenance personnel an easy approach onto the machine, opposed to having to hoist themself up a vertical ladder. This ease enables hands to be free for other needs, such as carrying tools. Even more so, the Hydraulic Ramp that we offer provides a flat surface that, can be utilized as an easy surface for dollies to be pulled up and, for

example loaded down with a bucket of grease. When you need to climb on the machine from the non-cab side you can either have a Standard Ladder or no ladder at all with a handrail in its place. And in the event of an emergency we now also offer one or two Emergency Ladders on the Non-Drill end of the machine. These ladders flip out with a quick release and provide a swift means of escape if need be. When they are not in use they fold up onto the rig and relatch. The main emphasis of these new ladder options is not for aesthetics, but instead to further ensure that there is a safe means of getting on and off the rig. The new options above allow for front or backwards ascent or descent from the machine. We want to try to get away from having to “climb on the rig,” but rather be able to easily access the decking in a more natural form.

Decking A main concern of all mines is working in a confined space. Drilling Solutions is currently exploring the balance of opening up workable areas as well as keeping the machine’s overall size in mind for transportation purposes and still allowing the mine to access those holes that might bring an operator close to the highwalls. We have developed options that will allow complete 360º access around the machine. This includes an option for complete walk-around access of the cab. This added selection can be used for inspection and for cleaning the windows for further visibility. Another part of the 360º access is a decking option that includes a built in bit basket on the Drill-End of the machine as well as a spot to store hammer subs. By adding this decking option, you not only gain complete access to the machine, but also have a safe, secure, and dedicated spot to store bits and hammers. This option inhibits bits from being laid unsecured on the deck, opening up a possibility for them to shift and move during tramming. One more part of the 360º access option that is available is an Extended Cooler decking. Prior to this option the only way to access the back of Blasthole Drilling in Open Pit Mining

Talking Technically

the coolers was by using a man-lift or some other similar means. By adding on this decking you add approximately 2 feet (61 cm) to the non-cab side of the machine. This allows unconstrained access to the back of the coolers for cleaning, maintenance or a walkway to other areas of the machine.

Energy isolation When working on any piece of machinery this size, there is the constant concern about isolating any energy, whether it be electrical, hydraulic, or pneumatic. The engineers at Drilling Solutions spend numerous hours designing and configuring different options with the goal of being able to give anyone with access to the machine a safe and secure piece of equipment to work on, complete with fail-safes when applicable. We know that the easier we make the machine to work on, the happier and safer all entities involved will be. One of the new options offered is a Ground-Level Battery and Starter Isolation box. Inside this box are lockable turn switches that either engage or disengage the power or the starter. There are also long-life LED lights that are color coded to designate whether it is receiving power, or if the power is off. The front cover on this box is comprised of a strong plexiglass piece so that you can see what energy state the machine is in without having to physically open the front cover. Again – we are of the mindset that the quicker and easier it is to use, the more it will be used. Another example of how we are isolating hydraulic energy is by utilizing a series of Hydrau-Flo Valves. These valves are specially designed to prevent fuel spillage, in the event of over-filling or tank rupture. Not only is this design a safe way to transfer fuel, but it is also environmentally friendly.

Ease of maintenance There are many new options offered straight from the factory that have greatly enhanced the ease of working on our machines. Keeping confined spaces in mind, as well as the idea that the less often a component needs to be serviced, the more production the machine

does in the dirt. When you choose the above option for cooler access decking, you also then have the opportunity to pick the Cooler Access Ladder. The Cooler Access Ladder is a stepladder integrated onto the decking and hand railing that provides a safe approach to accessing the radiator tank on top of the cooler for filling, checking, or maintenance. As a side note – pressure-relief safety caps are standard on all machine radiator tanks. These caps allow the pressure that naturally builds up in the tank to safely be released without the danger of spraying out hot coolant onto the individual. In regards to the powerpack, we now offer a dipstick for the gearbox. Prior to this the sight glass for the gearbox was in a hard to see area. Now it is easy to access and it provides a means to easily check the gearbox oil level daily or as required. We also have the new oil-centrifuge option that extends the life of the engine oil. It achieves this without filters to change or clean. We are providing new ground level service options in addition to the Ground-Level Battery and Starter Isolation. The first of these is a new ground level Live-Oil Sampling option. This option provides the ability to take samples for Hydraulic Oil, Engine Oil, and Compressor Oil. The oil continually circulates through this area so that all samples taken are “fresh.” Two more ground level service options that are available are the QuickFill Box and the Quick-Drain Box. These two boxes located on the non-drill end of the rig provide a simple means to either fill or drain the machine of its fluids. Each connection point is clearly labeled and consists of a safe quick connect, each differing in size to avoid cross contamination of fluids. Design teams at Atlas Copco are constantly getting feedback from customers or our own field service personnel. They let us know if something is working great, what can be improved, or if something needs to be completely redesigned. One of the steps that we are taking as a company is trying to phase out welding, and instead use bolt-in parts. This facilitates in both making it easier to change out parts and cuts down on possibly challenging

PV-270 new decking and access options.

PV-230 bit basket option. (Will be located on drum deck)

PV-270 ground level battery and starter isolation.

PV-270 overview of location of live sampling quickfill and quick drain.

From left: Close up view of live sampling, quickfill and quick drain.

Blasthole Drilling in Open Pit Mining 15

Talking Technically

Options

PV-230 RCS

Respa Filters



XIR Glass



PV-270 SEOH*

PV-270 RCS

PV-310





Hydraulic Hedweld Ladder









PV-351

Hedweld Spring Ladder







Atlas Copco Hydraulic Ladder

























Emergency Ladders



New Cab



Tower Access



● ●









Cable Reel Additional Tower Rest Water Tank Tropical Engine Roof





Stainless Steel Battery Boxes





Staniless Steel Electrical Boxes





Ground Level Battery Isolation & Jumpstart



Live Sampling



Under the Deck Misting







Secondary Rod Catcher



● ● ●

















Autcrane Option







Wormald Fire Suppression







Drum Deck Bit Holder







Protective Hose Sleeving







Dynaset Water Injection Pump







Secondary Air Conditioning Unit





Buddy Seat With Seatbelt











Cooler (Radiator Tank) Access





Engraved Hydraulic Schematic



















Centrifuge Engine Oil Filter



Gearbox Dipstick



Hydra-Flow Fuel System







360º Walk-Around Decking











Housing Option









● ●

Quick Fill Box







Quick Drain Box







Led lights







*SEOH = Non RCS, Standard Electric Over Hydraulic

the integrity of the material by welding and cutting. As an added bonus, the more components that we design to be bolted in rather than welded results in a more modular machine that can be customized specifically to the customers’ orders. One of these newly redesigned boltin options is the sheave and cable retainers that are on the PV-270 and PV-351 towers. Previously, when it was time to change out the cables, these pins and sheaves had to be removed. Now it is just a matter of loosening a few bolts, changing out the cable, and rebolting the roller back in. Another design that 16

has been modified is the feed cylinder supports on the PV-351’s. Again – it used to be that you would have to remove the feed cylinders to replace the worn guides. The guides now boltin as well. By constantly keeping ease of maintenance in mind, Atlas Copco Drilling Solutions are hopeful that it will result in more productivity hours for you and your mine; less down time means more drilling time. Regardless of what drilling rig you may own, or what piece of equipment you may work on, we here at Atlas Copco Drilling Solutions want you to always be conscious of your every

action on or around the mine site. Mining is not the safest in-dustry out there, but with everyone putting forth a little more effort towards always thinking SAFETY FIRST we feel that this will make a monumental difference in everyone’s life. As long as you do your part of ensuring that you are constantly thinking of your safety, you can rest assured that Atlas Copco Drilling Solutions will do all within its power when designing a machine to keep you just as safe.

Maureen Bohac

Blasthole Drilling in Open Pit Mining

Talking Technically

An introduction to surface mining The wealth of nations A well-accepted principle is that the wealth of a nation comes from the earth. In the world of mining, a corollary to this is that “If it can’t be grown, it must be mined.” Surface mining techniques are the principal means used to extract minerals from the ear th. The yearly rock production yielding metals, non-metals and coal in the world totals 16.6 billion tons*. Of this, the production from surface mines is about 70% or 11.5 billion tons. Crushed rock, sand and gravel - the fundamental materials required for construction - are largely produced using surface mining techniques. Their yearly production rate totals 23.5 billion tons. To this must be added the materials needed for the production of cement, another 2.3 billion tons. Finally, the amount of waste that must be moved in the process of extracting the valuable materials is estimated at 30 billion tons. Summing, one finds that the total amount of material extracted per year using surface mining techniques is of the order of 67.3 billion tons (Bagherpour et al, 2007). * 1 ton = 907 kg

An increasing demand Today, the population of the world stands at about 6.5 billion people. In simple terms, this means that every year approximately 10 tons of material is extracted using surface mining techniques for every person in the world. If one looks to the future, the UN estimates that in 20 years (2038) the world’s population will have reached about 8.5 billion people. By simply applying the current utilization rate of 10 tons/ person, one would expect the amount of material extracted yearly by surface mining techniques to climb to 85 billion tons. One must keep in mind, however, that today about 95% of the population growth is in the developing countries of the world. Based on their expectations for improved living standards

Photo: Copper mine in the southwest USA.

in the future, the actual estimate of materials mined using surface mining techniques in the year 2038 is 138 billion tons (Bagherpour et al, 2007). The ability of the earth to meet this type of demand is not really a question of resources, since they are clearly there, but rather a matter of price and cost. In looking at the mineral resource base, one must conclude that, in general, the mining conditions will be significantly more difficult than today. In addition, ever-increasing environmental and health and safety conditions are expected to be in place. This means that the entire mining process from prospecting to exploration to development to extraction and finally to reclamation will have to become much more advanced. In many places of the world today, mine closure must be fully and satisfactorily addressed before a surface mine can be opened. This translates into requirements for applying first rate

engineering and technology for meeting today’s requirements and especially those of the future. Atlas Copco is at the forefront in producing the equipment and technologies required today and for addressing the challenges of the future.

A brief synopsis of quarrying and open pit mining This introductory chapter will focus on those surface deposits that require the application of drilling and blasting techniques as part of the overall extraction process. Excluded from the discussion will be strip mining, the mining of sand and gravel deposits and the quarrying of dimension stone. As indicated, large quantities of raw materials are produced in various types of surface operations. Where the product is rock, the operations are known

Blasthole Drilling in Open Pit Mining 17

Talking Technically

Financial optimization 1. Capital and operating summation 2. Revenue 3. Cash flow statement 4. Marginal ore utilization 5. Rate of return

Refined ore reserves

Ore reserve analysis

1. Cutoff grade 2. Marginal analysis 3. Design alternatives

1. Break-even analysis 2. Drill-hole evaluation 3. Pit design 4. Marginal analysis

is obtained. By adding the desired production rate into the model a production schedule is generated. Based on the schedule, one determines the required equipment fleet, staffing, etc. to satisfy the schedule. This leads allows one to calculate the capital requirements and the operating costs. With these now-estimated rather than assumed costs, the ore reserves are re-examined and design alternatives evaluated. Eventually, an overall financial evaluation is performed. The double-headed arrows indicate the highly repetitive nature of the process.

Quarries Production scheduling

Equipment and facilities

1. Preproduction costs 2. Working room 3. Stripping ratios 4. Sequencing 5. Reclamation 6. Operating schedules 7. Financial 8. Constraints

1. Capital intensive 2. Equipment selection 3. Operating costs 4. Capital depreciation 5. selective mining

Figure 1. Financial optimization using circular analysis (Dohm, 1979).

as quarries. Where metallic ore or nonmetallic minerals are involved, they are called open pit mines. There are many common parameters both in design and in the choice of equipment. When examining a deposit for potential mining and even when expanding a current operation, one often employs a process called circular analysis. As

shown diagrammatically in Figure 1, the process consists of five components. Although the figure applies specifically for the open pit mining of ore deposits, a similar procedure is followed for quarries. One naturally begins with a description of the deposit and using some assumed costs a preliminary pit design

Figure 2. A diagrammatic representation of a quarry operation.

18

A rather simple but useful definition of a quarry is a factory that converts solid bedrock into crushed stone. Quarries can be either of the common pit type or, in mountainous terrain, the hillside type. Pit type quarries are opened up below the level of surrounding terrain and accessed by means of ramps (Figure 2). The excavation is often split into several benches depending on the minable depth of the deposit. When the terrain is rough and bulldozers cannot provide a flat floor, a top-hammer construction type drill rig can be used to establish the first bench. Once the first bench is prepared, production drilling is preferably carried out using DTH- or COPROD techniques. The excavated rock is crushed, screened, washed and separated into different size fractions, for subsequent sale and use. The amount of fines should be kept to a minimum. Not all types of rock are suitable as raw material for crushed stone. The material must have certain strength and hardness characteristics and the individual pieces should have a defined shape with a rough surface. Igneous rock such as granite and basalt as well as metamorphic rock such as gneiss are well suited for these purposes. Soft sedimentary rock and materials which break into flat, flaky pieces are generally unacceptable. The final products are used as raw material for chemical plants (such as limestone for cement manufacturing, the paper and steel industries), building products, and for concrete aggregates, highway construction, or other civil engineering projects. Blasthole Drilling in Open Pit Mining

Talking Technically

Open pit mines Two major differences between open pit mining and quarries are the geological conditions and the demands placed on the characteristics of the blasted material. For quarries, a majority of the rock products eventually delivered to the customers has only undergone crushing and screening in order to obtain the desired size fractions. An open pit metal mine, on the other hand, attempts to deliver the ore as pure as possible via crushers to a concentrator consisting of mills, separators, flotation and/or biochemical systems, etc. The resulting concentrates/products are eventually sent for further processing before emerging as a final product. For certain metals, this latter process involves smelting and refining. The deposits mined using open pit methods have a variety of sizes, shapes and orientations. Sometimes the distinction between the valuable material and the waste is sharp such as shown in Figure 3 and in other cases the distinction is more subtle - based upon economics. As in quarries, the minerals are extracted using a series of benches. If the orebody does not outcrop, the overlying material must first be stripped away to expose the ore. As the initial pit is deepened, it is widened. The pit geometry is controlled by a number of factors including orebody shape, grade distribution, the stability of the slopes, the need to provide access, operating considerations, etc. For the geometry shown in Figure 3, a significant amount of waste must be removed (stripped) to access the next bench of ore at the pit bottom. Without jeopardizing slope stability, it

Waste Bench slope 72o

Good slope stability

y

Pit slope 45o

Or eb od

Quarries are often run by operators who sell their products to nearby contractors and road administrators. Because the products are generally of relatively low value, they are transport cost sensitive. Hence, wherever possible, quarries are discreetly located as close as feasible to the market. Special measures are required to minimize adverse environmental impacts such as noise from drilling, vibrations from blasting, and dust from crushing and screening to the neighboring areas.

Good fragmentation needed

Figure 3. General principles of open pit mining.

is of prime importance to keep the pit slope angle as steep as possible, thereby keeping the excavated waste to a minimum. There becomes a point where the quality of the material contained in the next “ore” bench is not sufficiently high to pay the costs of the associated waste. At this point in time either the open pit mine closes or, if conditions are

favorable, continuation may proceed using some type of underground method. Figure 4 shows the Aitik copper/gold mine in northern Sweden. It is Europe’s largest copper mine producing 18 Mton of ore per year. Currently at a depth of 480 m it is expected to reach of depth of 800 m before decommissioning. The Bingham Canyon mine in Utah (Figure 5)

Figure 4. The Aitik mine in northern Sweden (www.boliden.com).

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Talking Technically

Orebody

Drilling

Overall fragmentation system

Blasting

Loading

Hauling

Mine Mill

Primary crushing

Secondary crushing

Grinding

Further treatment

Figure 5. The Bingham Canyon copper mine near Salt Lake City, Utah, USA. (www.kennecott.com)

has been in production since 1906 and is one of the largest man-made structures in the world, measuring 1200 m

deep and 4400 m across the top. It has produced more copper than any other mine in history and has many

Figure 6. Diagrammatic representation of the overall mine-mill fragmentation system and the mine and mill subsystems (Hustrulid, 1999).

years remaining. With respect to waste removal, the fragmentation demands are simple. Since, the material is not required to pass through a crusher, the maximum size is controlled by the limitations imposed by the equipment used to load and haul the material to the waste dump. On the other hand, good fragmentation of the blasted ore offers great savings in the total costs of the mineral dressing process.

Some forward thinking

Photo: Blasthole drilling of 40 ft (12 m) benches at Newmont's Phoenix mine, Nevada, USA. See page 117.

20

Extraction of the valuable mineral whether in quarries or open pits requires a number of unit operations. Generally, the rock is drilled, blasted, loaded, hauled to a primary crusher and then transported further to a plant of some type for further processing. Figure 6 shows a schematic of the process. Often, mines are organized so that the individual unit operations are separate cost centers. Although there are advantages to this approach, one result, Blasthole Drilling in Open Pit Mining

Talking Technically

Insitu

Drilling Specified Drill Pattern

Drilling

Blasting

Internal environment Minimum wall damage

Blast Engineering

External environment Minimum: Flyrock, noise, airblast, ground vibration

Loading & Haulage

Primary crushing

Secondary crushing

Fragmentation

Conveyor

Loading & Haulage Good: Fragmentation, Pile shape, diggability

Primary crusher

Grinding

Transport

High throughput and bridging preventation

Further treatment

Secondary crushing & grinding Efficient crushing and grinding feed

Figure 7. The mine-mill system represented as fragmentation and transport unit operations (Hustrulid, 1999).

Figure 8. Simplified view of the five different stages of fragmentation, each with a different energy product profile.

unfortunately, can be that the individual managers look at minimizing the cost of their center rather than on the overall objective of overall cost minimization. In reviewing the components in Figure 6, it can be shown that they can be replaced by two operations, fragmentation and transport. In the simplified view shown in Figure 7, there are five different stages of fragmentation each with a different energy – product profile. One must carefully examine the best opportunities for applying fragmentation energy in the various stages on the final product cost. For example, increased fragmentation energy can be relatively easily introduced in the mine by modifying the drill patterns and explosive characteristics. This action may provide an inexpensive alternative to adding the fragmentation energy in the grinding circuit. This process of considering all elements of the fragmentation system, logically dubbed “mine-to-mill” is a recognized part of

mine-mill optimization. In addition to production, there are some other important customers for blast engineering. One is termed the “Internal Environment” and the other the “External Environment.” These are shown in Figure 8. Both for safety and economic reasons, it is important to preserve the integrity of the pit wall. Large diameter blast holes, energetic explosives and wide patterns will be used in the production blasts which will be subsequently loaded out using large excavators and haulage units. Near the pit wall, much more precise techniques involving smaller diameter holes, specially designed explosives, and special timing procedures are employed to minimize wall damage (Figure 9). Unless great care is taken, large loading equipment can easily spoil the results of the trim blasting. The result is that special loading and hauling fleets may be required. Failure to protect the pit walls, translates into the need for flatter slopes

and additional waste removal and/or the loss of reserves. These, in turn, translate into higher overall costs for the mining operation. In carrying out an evaluation of the appropriate drilling and blasting practices, emphasizing mine-to-mill aspects without taking into account the care of the slopes can result in lower production costs but at the sake of higher investment (capital) costs due to greater stripping or lost reserves. Therefore care must be taken to include all the costs when making the analysis. The “external environment” component falls into the category of a potential “show-stopper” since if proper measures are not taken to fully comply with standards, the operation could very well be shut down.

Final remarks Atlas Copco has the advantage of long experience in all types of surface drilling operations, with a product range to match. With its history of innovative

Blasthole Drilling in Open Pit Mining 21

Talking Technically

Figure 9. Near the pit wall more precise techniques are employed to minimize wall damage.

engineering, the company tends to think forward, and is able to advise the user on improving design elements of the operation that will result in overall cost savings.

William Hustrulid Hans Fernberg

References

Bagherpour, R., and Tudeshki, H. 2007. Material handling in worldwide surface mines. Aggregates International. Pp 10-14. June. Dohm, G.C., Jr. 1979. Circular analysis – Open pit optimization. Chapter 21 in Open Pit Mine Planning and Design (J.T. Crawford, III and William A. Hustrulid, editors). AIME. Pp 281-310. Hustrulid, William. 1999. Blasting Principles for Open Pit Mining. A.A. Balkema, Rotterdam. Fernberg, Hans 2002, New trends in open pits, Mining and Construction 1-2002

22

Photo: Blasthole drilling and haulage at a mine in the southwest USA.

Blasthole Drilling in Open Pit Mining

Talking Technically

Putting rotary drilling into perspective

Atlas Copco’s largest drill, the Pit Viper 351E, operates on a blast pattern at an open pit copper mine. Rotary blasthole drills are the predominant method of drilling 9 inch (229 mm) diameter holes or greater.

Mining prosperity Atlas Copco offers a complete range of rotary as well as DTH and tophammer drill rigs for most types of open pit mining and quarrying applications. But how do these technologies complement each other and how do drillers know which method to choose, and when?

A complete range With the acquisition of IngersollRand’s Drilling Solutions, Baker Hughes Mining Tools (BHMT) and Thiessen Team businesses, Atlas Copco has a complete range of products to offer to large quarries and open pit mines. Much of the world’s mining output begins through drilling of holes with rotary

drills. Ingersoll-Rand built air-powered rotary drills for many years prior to the introduction of their first fully hydraulic unit, the T4, in 1968.

About rotary drills It is important to note that rotary drills are capable of two methods of drilling. The majority of the units operate as pure rotary drills, driving tricone or fixed-type bits. The fixed-type bits, such as claw or drag bits, have no moving parts and cut through rock by shearing it. Thus, these bits are limited to the softest material. The other method utilized by rotary drill rigs is down-thehole (DTH) drilling. High-pressure air compressors are used to provide compressed air through the drillstring to drive the DTH hammer (See illustration next page). The primary difference

between rotary drilling and other methods is the absence of percussion. In most rotary applications, the preferred bit is the tricone bit. Tricone bits rely on crushing and spalling the rock. This is accomplished through transferring downforce, known as pulldown, to the bit while rotating in order to drive the carbides into the rock as the three cones rotate around their respective axis. Rotation is provided by a hydraulic or electric motor-driven gearbox (called a rotary head) that moves up and down the tower via a feed system. Feed systems utilize cables, chains or rack-andpinion mechanisms driven by hydraulic cylinders, hydraulic motors or electric motors. The preference at Atlas Copco is to use cables for pulldown, as they are lightweight and inexpensive, and allow easier detection of wear to help avoid catastrophic failures.

Blasthole Drilling in Open Pit Mining 23

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Pulldown Pulldown is the force generated by the feed system. The actual weight on bit, or bit load, is the pulldown plus any dead weight such as the rotary head, drill rods and cables.

More weight with rotary

The tower supports the drill string during drilling as well as the rotation head and feed system.

Down-The-Hole method

Rotary drilling method TONS

Principle:

The hammer is situated down the hole in direct contact with the drill bit. The hammer piston strikes the drill bit, resulting in an efficient transmission of the impact energy and insignificant power losses with the hole depth. The method is widely used for drilling long holes, not only for blasting, but also for water wells, shallow gas and oil wells, and for geo-thermal wells. In mining it is also developed for sampling using the reverse circulation technique (RC drilling).

24

Principle:

Rotation is provided by a hydraulic or electric motor driven gearbox, called a rotary head, that moves up and down the tower via a feed system, generating the pulldown required to give sufficient weight on the bit. Flushing of drill cuttings between the wall of the hole and the drill rods is normally done with compressed air.

It only takes one look to see that the biggest DTH and tophammer drill rigs are very different than the biggest rotary blasthole rigs. In fact, the PV-351 rotary drill rig weighs in excess of nine times that of Atlas Copco's largest DTH hammer drill rig, the SmartROC D65. Yet the PV-351 is drilling a hole that is generally only twice the diameter. Take a typical medium formation tricone bit with a recommended maximum loading of 900 kg/cm of bit diameter (5000 lb per inch of diameter). With a 200 mm (7-7/8 in) bit, you could run about 18,000 kg (40,000 lb) of weight on the bit. The laws of physics dictate that for every action, there is an equal and opposite reaction, meaning that if you push on the ground with 18,000 kg (40,000 lb), the same force will push back on the unit. Therefore, the weight of the machine must be over 18,000 kg (40,000 lb) at the location of the drill string to avoid the machine “lifting off” the jacks. To achieve a stable platform through proper placement of the tracks and levelling jacks, the distribution of weight results in an overall machine weight that approaches or exceeds twice the bit load rating. This weight does add cost to the machine, but the size of the components also translates to long life. Even smaller rotary blasthole drills are built to run 30,000 hours of operation, and some of the large blasthole drills have clocked over 100,000 hours of use.

Rig design With the exception of one model, the rubber-tire mounted T4BH, Atlas Copco’s rotary blasthole drills are mounted on excavator style undercarriages. Powerful hydraulic-drive systems allow the machine to tram over a variety of ground conditions, though rotary blasthole drills should always operate on firm, flat benches. Blasthole Drilling in Open Pit Mining

Talking Technically

The key component of a rotary blasthole drill is the tower, which is sometimes referred to as the derrick or mast. Atlas Copco towers are four main member, open front structures in which the rotary head slides up and down via a guide system. The length and weight of the tower ultimately dictates the size of the mainframe and undercarriage. Most drilling functions are hydraulically driven. Powering these hydraulic systems, along with the air compressor is a diesel engine or electric motor. Most rotary drills are diesel powered for good mobility. Electric powered units offer some advantages such as lower power cost (in most areas), no diesel emissions, no refueling requirement and less maintenance. However, some operations are not setup with the proper electrical infrastructure or staffing to run electric units. Even when electric power is available, many customers avoid electric drills as the trailing cable used to provide power makes it harder to move the unit between holes or patterns. Generally, electric power is preferred on large single-pass units used in major open pit metals mines where electric shovels are employed, though electric power is now available on smaller units such as the Atlas Copco PV-271, PV-275 and DML.

The importance of air A key parameter of rotary drilling is flushing the cuttings from the hole. In most rotary blasthole drills, cuttings are lifted between the wall of the hole and the drill rods by compressed air. Sufficient air volume is required to lift these cuttings. Many types of tricone bits have been developed to meet various drilling needs. Softer formation bits are built with long carbides with wide spacing on the face of the bit. This design yields large cuttings which increase drill speed and reduce dust. It is important to have sufficient clearance between the wall of the hole and the drill rods in order for such large cuttings to pass. If this clearance, known as annular area, is not sufficient, the cuttings will be ground between the wall of the hole and the rods or by the bit itself (called regrinding) until they are small enough to exit the hole. This results in

The drilling platform is supported by a crawler undercarriage except during drilling when it is raised up by hydraulic jacks.

excess dust and accelerated wear on the bit and drill rod.

Bailing velocity A traditional rule-of-thumb is a minimum of 1,525 m 3/min (5000 cfm) of uphole velocity, the speed at which air exits the hole. The actual amount of air required will vary widely based on the density of the material and the size of the cuttings. Dense cuttings as found in iron ore mines will settle much quicker than lightweight overburden in coal mines and thus need more air coming up the hole to lift them; 1,525 m3/min (5000 cfm) may not be enough. However, harder material is generally drilled with hard formation bits that utilize shorter cutting structures, thus yielding smaller chips. Conversely, some soft material can be drilled effectively with only 915 m 3/min (3000 cfm) uphole velocity. Unfortunately, many operations have tried to increase uphole velocity by increasing the diameter of the drill rod.

The ability to carry long drill rods up to 70 feet provides more time for drilling.

Blasthole Drilling in Open Pit Mining 25

Talking Technically

This is obviously much easier than getting a larger air compressor by retrofitting or purchasing a new machine. In some conditions, this strategy works, but more often, the reduced annular area results in increased wear and dust and the drill rate may even drop. Whatever the application, it is critical to have proper bailing air.

Dust control

Rotary drilling with tricone bits is the most cost efficient method for large hole diameters.

To control the dust, the area around the hole is surrounded by a dust hood.

A necessary evil created by the air compressor in drilling operations is the generation of dust. To control the dust, the area surrounding the hole is enclosed by a dust hood. Dust hoods are sealed on the sides by dust curtains, and where the rod comes through the deck by a rod wiper or dust seal. A dust control system must be used in conjunction with the dust hood and curtains. The two most popular types of dust control are dry dust collectors and water injection. Dust collectors are essentially large vacuum cleaners that pull the dust away from the dust hood and run it through a collection of filter elements. Water injection systems inject a fine amount of water into the air stream. Water injection is the more effective solution for ensuring dust is minimized, but the introduction of water into the hole can slow down the drilling process by increasing the density of the cuttings at the bottom of the hole that the air compressor must move. Water injection systems require frequent refilling of the water tanks, and in freezing conditions, elaborate heating systems must be used. Dust collectors offer a productivity advantage, but they can become plugged if not turned off when wet material is encountered. This is particularly a problem if the wet material freezes in the system.

When rotary is better

Large diameter holes produced by rotary drills, such as this Pit Viper 351, yield blast patterns with wider burden and spacing, resulting in fewer holes.

26

Every drilling application is different, so we cannot say that there are particular breakpoints where you should transition between drilling methods. Generally, drilling below 152 mm (6 in) is best accomplished with tophammer units. Above this diameter, it is typically done with a rotary rig, although tophammer units are doing some of this Blasthole Drilling in Open Pit Mining

Talking Technically

ø

APPLICATIONS

PRODUCT RANGE DIAGRAM Dimension stone industry Construction Aggregate (Cement and Limestone) Industrial minerals (Cement & Limestone) Gold and precious metals Coal Copper and base metals Iron and ferrous metals 1" 25 mm

2" 51 mm

3" 76 mm

4" 102 mm

5" 127 mm

6" 152 mm

7" 178 mm

8" 203 mm

9" 229 mm

10" 254 mm

11" 279 mm

12" 305 mm

13" 330 mm

14" 356 mm

15" 381 mm

16" 406 mm

Pit Viper 351 ROTARY DRILLING PRODUCTS

Pit Viper 311 DM-M3 Pit Viper 275 Pit Viper 271 Pit Viper 235 DML DML-SP DM45 / 50 T4BH DM30 II DM30

PERCUSSIVE DRILLING PRODUCTS

DM25-SP SmartROC D65 FlexiROC D65 FlexiROC D60 AirROC D65 PowerROC D55 FlexiROC C65 FlexiROC D55 ROC L7 FlexiROC T50 AirROC D55 AirROC D50 FlexiROC D50 ROC F6 AirROC D40 AirROC D45 SH ROC F9CR ROC F9 SmartROC T45 SmartROC T40 FlexiROC T40/R SmartROC T35 AirROC D35 FlexiROC T35/R PowerROC T35/E AirROC T35 ROC D3 RRC ROC D3 PowerROC T25/E AirROC T25

Atlas Copco Drilling Solutions division

Atlas Copco Surface Drilling Division

Rotary Rotary / DTH DTH COPROD Tophammer

AirROC T25 W

FlexiROC T20R FlexiROC T15R

Rotary drilling with tricone bits is the most cost efficient method for large hole diameters.

work effectively with the introduction of larger platforms and more powerful rock drills. For harder material, say above 100 MPa (15,000 psi), unconfined compressive strength (UCS), DTH is often faster than pure rotary drilling if provided there is enough air pressure on board. Simply looking at our product range (see above) gives an indication of which methods are commonly used for the different diameters found in construction and mining. There are certain limitations imposed on each method of drilling. With tophammer percussive drills, the

power of the rock drill itself limits the ability to transmit adequate force to larger diameter bits, especially at deeper depths when percussive energy is successively reduced with each new rod connection. Down-the-hole (DTH) tools solve this energy loss problem, but their maximum hole diameter is limited by the volume of air. To build the air pressure that translates directly to impact energy, a certain volume of air is required. Take for example a Secoroc QL80 203 mm (8 in) DTH hammer that is designed to operate at 25 bar (350 psi). Even with our largest high pressure compressor

686 41 m3/min (1,450 cfm), the pressure will only build to 23 bar (325 psi), thus providing less impact energy. In real terms, each blow of the piston is about 45 kg (100 lb) less than it is designed for. In some cases, this method will still outperform rotary drilling.For most large diameter blasthole drilling, there is simply not enough air onboard for a DTH to be as cost effective as rotary drilling with a tricone bit. Rotary drilling is still the predominant method of drilling 230 mm (9 in) diameter or greater. This is driven primarily by the current limitations of

Blasthole Drilling in Open Pit Mining 27

Talking Technically

Total Drilling Cost (TDC) related to bit life and productivity 14,000

$ 9,00

Footage/24 Hours Bit Life (ft) Overall Cost/Ft

$ 7,50

10,000 $ 6,00 8,000 $ 4,50 6,000

4,000

300 ft/hour, 1500' bit life

$ 3,00

High Production

2,000

Overall Cost/Foot

Footage/24 Hours & Average Bit Life

12,000

215 ft/hour, 5500' bit life Lowest Cost

75 ft/hour, 12,000' bit life

$ 1,50

Great Bit Life

$0

0 Bit Life vs Production 2012 update (1) (Cost vs. Bit Life & Production)

tophammer units and rig air systems. Tricone bits also become more cost effective as the larger bits are equipped with larger bearings which in turn can handle higher loads. These higher loads translate to improved drill rates. Another advantage of rotary rigs is the length of the drill rods that can be carried on board. Longer rods mean fewer connections. Smaller rotary blasthole machines utilize 9.1 meter (30 ft) length rods, while larger units are capable of running 10.7 meter (35 ft) or 12.2 meter (40 ft) rods. By comparison, tophammer or DTH crawler drills use drill steel that is generally 6.1 meters (20 ft) or less in length. Further, some rotary rigs are large enough to handle a long tower that enables drilling of the entire bench height in a single pass. At the largest open pit mines, rotary units are drilling 20 m (65 ft) deep holes in a single pass to match the bench heights dictated by the large electric shovels that can dig a 17 m (55 ft) bench.

Productivity versus cost Studies have shown that pure penetration rate will increase linearly with increased pulldown. The same has also 28

been said of rotation speed. So why doesn’t every operation use more of each? Unfortunately, higher pulldown and rpm usually results in increased vibration and lower bit life. The vibration causes increased wear-and-tear on the rig, but more importantly, it creates a very unpleasant environment for the operator. What invariably happens is that the operator reduces the weight or rpm until the vibration returns to a comfortable level. Some operations limit bit load and rpm even if there is no vibration in order to improve bit life. This is often the wrong strategy as the overall drilling cost per unit, also known as Total Drilling Cost (TDC), should be considered. TDC is calculated using the bit cost per meter/foot and the total rig cost per hour. The unit cost per hour includes labor, maintenance and power, and possibly capital cost. The drilling speed really doesn’t impact this cost-per-hour figure. What it does impact though is the cost per unit produced (cost/meter/foot, cost/ton, etc…). You generally want to push the rig harder to reduce the cost/foot, but there will be a point where the rig overloads the bits (see diagram).

Large versus small There are some drawbacks to rotary rigs. Smaller crawler rigs are more flexible with many advantages such as articulating and extendable booms and guides that allow drilling at many different angles. Unlike crawler rigs, the components on rotary rigs are often not enclosed. They are mounted onto the frame in an open layout that makes them extremely easy to service. Large electric units normally have a machinery house to protect the electrical drive components, and newer midrange sized blasthole units such as the PV-235 have the option of a machine enclosure. The general trend for 165 mm (6-1/2 in) or less is towards the smaller, more flexible units. However, many large scale quarries and small mines still favor the durability, life and simplicity of the larger rotary rigs for these small diameters. For the large scale open pit operations that yield a high percentage of the total worldwide mineral production, it is anticipated that rotary drilling will remain the primary method for years to come.

Brian Fox Blasthole Drilling in Open Pit Mining

Talking Technically

Automated surface blasthole drilling Utilizing the RCS technology platform The current series of Atlas Copco Pit Viper drill rigs is based on the latest, well proven computer and information technology. These drill rigs are of modularized design in both hardware and software, so upgrades of the latest technology are available for older models. Several options are available to facilitate quality drilling. Atlas Copco has applied the same new automation technology for other underground drilling equipment such as Simba production drill rigs, Boltec rockbolting rigs, and ROC surface crawler rigs. For the customer, this means commonality of components and training, leading to a better understanding of both the capability and the maintenance of Atlas Copco products. For the company, it allows continuous product development, which can be applied straight across the range.

Introduction Atlas Copco has introduced a number of new drill rigs for the Drilling Solutions Division using a common technology platform. This approach allows development of new functionalities for the drill rigs, which experience has shown in both underground drilling and haulage as well as surface drilling. The current generation of machines is designed for high productivity, quality drilling and a comfortable working environment for the operator. Drilling a hole constitutes a small amount of the direct cost and time of mining, but has a major impact on the other production processes because it affects fragmentation, backbreak, underbreak, wall control, loading, haulage and processing. Although great attention is paid to penetration rate and wear of drill steel and bits, Atlas Copco is also interested in what drilling can do to improve rock excavation overall. The inputs to this ongoing process come from customers and from research projects where new technology is applied to drilling operations.

RCS is Atlas Copco’s technology platform.

PV-275 cabin with RCS provides an excellent operator´s environment and improved drilling performance.

Blasthole Drilling in Open Pit Mining 29

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RCS cabin on a PV-351.

The control system replaces the electric/hydraulic joystick and console layout pictured here.

Rig Control System

surface blasthole machines, the flexibility of the system is highly utilized and can be adapted and configured for all different types of products. Customers can start at a low level of automation and, as their requirements change, can upgrade. New functionality can be added without major rebuilding of the machines.

The automation platform for Atlas Copco blasthole drilling equipment is the Rig Control System (RCS), which is based on standard PC-computer technology. The new generation of RCS rigs has taken a quantum leap forward with respect to logging capabilities, serviceability and drilling accuracy. CAN-bus technology provides the backbone of this new rig control system. It is flexible and easily expandable, allowing new units to be added anywhere along the data bus by cable. The electronic modules are all developed solely for the RCS rigs, and are ruggedized and protected from external magnetic and electric influences. For

RCS cabin on a PV-270 series.

30

Common automation All Pit Vipers can be equipped with RCS Basic, which provides a number of safety and interlock features and a series of options– Autolevel, Autodrilling, GPS hole navigation, Rig Remote Access (RRA) and communication, wireless remote tramming, Measure While Drilling

(MWD) data log files, and International Rock Excavation Data Exchange System (IREDES).

Safety features The RCS Basic provides the machine with additional standard interlocks compared to the electric-over-hydraulic machines. A few of the interlocks created with the software are: • Hole depth indicator – displays the rotary head position as well as the depth of the hole drilled; • Pipe in hole tram interlock – rotary head must be in a safe position to allow tramming; • Jack interlock – pipe in the hole will disable jack functions to protect the machine and reduce bending of rods; • Rod support interlock – prevents damage of the rotary head and rod support by not allowing feed with rod support not in the stowed position; • Carousel no-bump – prevents damage to the carousel by limiting pulldown pressure with the carousel not in the stowed position; • Breakout wrench protection – prevents damage to the breakout wrench by disabling pulldown with wrench not in the stowed position; • Engine and electric motor information displayed over the touch screen maintenance screens; • Low fuel, lube and water level messages; and • Tram interlocks, so a trigger must be activated to allow tram function. Blasthole Drilling in Open Pit Mining

Talking Technically

On the panel 1. Auto interlock button. Press and hold this first and then choose one of the following auto functions. 2. Using multilever rocker switch. Autolevels up for switch up. Autodelevels for down in drill mode. 3. Autodrill. Drills to predefined depth and returns head to propel safe position. Anti-jam, void detection and so on in drill mode. 4. Future option. Auto tramming or autonomous operation. RCS Automated Function Buttons.

Autolevel/Autodelevel To increase the quality in setup of the drill, leveling the machine on the jacks is performed automatically. This will help an average operator to close the gap to the skill level of an expert operator. Installation of this feature will reduce wear and tear on the machine structure by limiting torsional effect on the mainframe and tower while leveling. This function's performance, of course, depends on ground conditions, but for a normal bench flatness, the results are that leveling is done in less than 35 seconds with an accuracy in pitch and roll to 0.2 degrees. Well

structured and integrated fault handling is vital for Autolevel/Autodelevel. This is to avoid unwanted tip over of the drill in case of uneven ground conditions or internal component faults.

Autodrilling In many cases there are several types of rock conditions within one blasthole, and an operator must be alert at all times to react to these varying ground conditions. With Autodrilling, computers are now the operators reacting to feedback from the machine’s gauges. Atlas Copco's autodrill feature has reproduced the expert operator's reactions into an automatic drill control. When activated, this function will detect the rock when the bit touches the ground, and start your air, water, rotation and feed to collar the hole. After the collared distance has been met, then this module will adjust air, water, rotation and feed to a drilling setting. This feature will apply optimal pulldown and rotation to try and drill as fast as possible without stalling the rotation or getting stuck. Once the target depth has been hit, the autodrill feature will clean the hole or flush the hole, shut off the air and water and then return the bit to a tramming-safe position. This feature provides the consistency of drilling to the correct hole depth, and a consistent water flow to maintain the hole so it does not collapse. Currently this is available for single pass drilling and multi-pass drilling, although a manual rod change must be made at this time.

GPS navigation screen.

Drill dashboard - drilling screen.

Leveling screen.

Settings screen.

Autodrill diagram

Hole building

Start

Rock contact detection

Collaring

Drilling

Hole cleaning

Finished

Anti-jamming / vibration control

This diagram is valid for a single-pass drill. For multi-pass drills a rod handling system sequence is added to the Autodrill sequence, which is currently not developed for rotary drills.

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RCS shows its flexibility through mine integration and diverse options.

GPS hole navigation To ensure the blasthole is precisely positioned where the mine engineer has designed the blast pattern and is drilled to the correct depth, GPS hole navigation has been developed for the RCS platform. This hole navigation system uses antennas mounted on the tower rest and radio antennas on the cab to produce an accurate bit position. Drill plans designed with the local mine coordinates are imported to the system, and the bit position is provided in real time. The bit position is very accurate and is calculated by taking into consideration the variability on the bench, providing the operator with the correct depth to drill each specific hole. This feature also provides a moving map display with zoom functions as the rig is trammed closer to the desired blasthole location. The dominant system for positioning of a rotary drill on a blasthole drill plan is with satellite navigation based on GPS or GPS and Glonass. Accuracies up to ±10 cm are possible to reach depending on installation and number of available satellites. The integration of the GPS receiver to the control system is via a standard RS serial link. Protocol used is preferably the standardized NMEA0183. The advantage of having the GPS system as a positioning sensor enables customers to choose products of any brand (Trimble, Leica, Topcon) depending on the preferred standard in the actual mine. 32

Rig Remote Access and communication The Rig Remote Access (RRA) system from Atlas Copco gives a customer the ability to connect the drill rigs to a standard computer network on a work site. The RRA system allows access information on the drill rigs from any authorized point in a network. The RRA system basically consists of a communication server onboard the drill rig and a network adapter. The server supplies the user with three functions: a web server that can connect to any standard web browser, an FTP server to enable transferring of data (files) to and from the drill rig, and a server process that enables any data to be integrated into the user's administrative systems. If a commercially available "office" network is used on the work site, which is easy to install into the existing infrastructure, it restricts the RRA functionality to only remote access, and does not permit remote control. Standard communication equipment is also used that makes the RRA easy to upgrade and adapt to new and more effective equipment when available. The system also utilizes standard communication protocols such as PPP or TCP/IP. With a wireless network connection to the drill rig, a number of working procedures in the mine are simplified and several new features are available to the mine planning organization. The basic mine planning

and control functions can be simplified substantially by having a direct link to the machines. Advanced work orders that previously were distributed at the beginning of each shift can now be distributed instantly. This leads to a more flexible and adaptable production organization. Computer designed drill plans and work orders that earlier had to be loaded manually with a PC card can now be downloaded directly from the office computer where they were created. This saves time and personnel and also allows last minute changes in order to adapt to variations in geology and ore geometry. Log files generated during drilling, also previously transferred from the rig with a PC-card, can now be collected from any computer connected to the network. This means that information carried by the log files, e.g. production data, geological and geomechanical data (strata recognition) is available for the entire organization as soon as the drill completes its hole/pattern. Manual shift reports stating number of holes, drilled depth, etc. can now be completed automatically from data logs without human involvement. RRA is also a tool for more advanced service and maintenance procedures. The operation of the rig can be followed remotely and monitoring of drill rig status can be made online using a standard web browser on a remote PC. “Web pages” are set up similar to the native RCS display on the rig. Troubleshooting can be done remotely using the built-in menus in the RCS system. This can also be done by specialized technicians and engineers at Atlas Copco's product companies. Furthermore, entire replacement of the RCS software has been done remotely from Örebro, the Rocktec office. The RRA system has been introduced to a number of underground mines and construction sites since 2003, which has eased implementation in surface mining operations.

Wireless remote tramming The wireless remote tramming function allows the operator to tram a Pit Viper from the bench within a 60-meter Blasthole Drilling in Open Pit Mining

Talking Technically

distance. This will allow an operator to walk all the way around the machine and tram the rig to avoid any blind spots or next to a highwall or berm to prevent damage to the machine. This controller is also equipped with safety triggers, so the operator must have control of the unit with his hands to tram the machine. The function has an emergency stop button and engine speed control as well, and can be equipped with additional functions when available.

IREDES The data that is transmitted to and from a drill rig or any other mining equipment is arranged in a specific format. Often different equipment suppliers use their own specific format, allowing data communication only between their own equipment. For a mining company or a contractor, an industry standard will simplify integration of equipment from different suppliers. Atlas Copco was one of the originators of the International Rock Excavation Data Exchange Standard (IREDES) initiative in 2000. A positive and open attitude between the IREDES members has led to data profiles for the different processes in the rock excavation process – drilling, loading and blasting. Atlas Copco is fully committed to the IREDES standard and the rotary drilling product line is IREDES compliant.

Measure While Drilling Measure While Drilling (MWD), strata logging, logs several drill parameters during production drilling, and the data can be used for prediction of geological and geochemical variations within drill patterns on a bench. This can help determine the strength of that specific rock type. A rock mass is also intersected by fractures and faults that strongly influence the conditions of the rock mass and, therefore, engineering aspects such as charging and blasting of the drill pattern. This data, when integrated with the blasting plan, should influence the explosive charging and specific density applied throughout the pattern, which will in turn influence the loading, hauling and processing of the ore.

Teleremote office installation. Inset: Wireless remote control, compact portable package.

Teleremote operation This feature uses the mine's wireless network, either 2.4 or 5.2 GHz frequency, and allows an operator to utilize the machine functions from a remote location including, drilling leveling, tramming, and GPS hole navigation. A dedicated communication channel that guarantees bandwidth and latency times for real time control of the drill is required. The package can be equipped with a four-camera system that is compressed to limit bandwidth for viewing of the machine from remote locations. This module also includes a dedicated safety system independent of the RCS package. If communication is lost between the remote station and the machine, it will shut down. Additional safety systems like personnel detection systems or systems detecting when people enter the working area should be combined with the mine's specific safety instructions.

Autotramming Autotramming is a feature in the development stages and has been tested on a machine at the Garland, Texas, factory. This component utilizes the GPS hole navigation system or can be deployed with an augmented GPS using the standard NMEA string to tram a machine between holes on a blasthole pattern. This pattern is interpreted by the path planner, which is in communi-

cation with the drill regarding direction and track speed to tram the machine at an ideal speed to the exact location. This module can reduce wear and tear on the machine structures as well as undercarriage by reducing spot turning and planning a correct path to the next hole. The current requirement for this feature is a "flat" bench, which must be verified by a mine engineer, to allow this machine to stay within its limits. A combination of any or all of these features are available for deployment to fulfill a specific mine's needs for automation. Additional feedback will be required in the future to further enhance the automation package, but the RCS is Atlas Copco Drilling Solutions' platform for automation.

Autonomous Pit Viper Operations Automating Pit Viper functions have been the backbone of RCS. Since its inception on ADS drills in 2006, the RCS product portfolio has grown through a planned evolution. This growth in RCS options has focused on creating autonomous drill elements, network integration, streaming data, precise navigation, and remote control. Capitalizing on this proven platform provides a solid foundation for the Autonomous Pit Viper. A multifaceted approach was taken to define the

Blasthole Drilling in Open Pit Mining 33

Talking Technically

deal with fatigue, breaks in the schedule (operational delays), along with a list of additional variables. The autonomous Pit Viper combines the proven existing automated functions into a complete drilling process to include AutoNavigation and Auto Rod Changing (ARC). The drill is prepared to take on the challenges of completing a pattern. A cold winter day (-36 °C) at the Aitik mine in Sweden, a perfect place for automation testing.

Integration

Autonomous mining breathes efficiency by definition. A major component to that is proper and flexible means of integration in subsystems. The Pit Viper’s software and hardware have been engineered around f lexibility where each meets mine processes and physical integration points. Standard data flows, hardware standards (not brands) and network integration vs independent networks are each keys to success. Each integration point was designed around public/universal standards or where none exist, adaptable solutions were created using standard protocols.

Efficiency

The newly developed client offers drill fleet awareness in an autonomous environment.

autonomous capabilities with respect to Pit Vipers. This twofold definition provides the outline of a complete solution; documenting machine control and data exchange.

around safety, and compatible for integration directly impactingefficiencies in the drill and blast process

Safety

Data Exchange: Data transfer to and from the drill to a centralized machine server. Server to compute internal data for use and transfer external data to 3rd parties in a standardized format.

Moving drill operations from the drill to an operations center creates an added layer of safety for a mine and its personnel. The unmanned Pit Viper drill maintains safety through obstacle awareness, visual and switched safe to board process and a precautionary staged approach to degradations that could be encountered in GPS and communication networks. All current safety interlocks will remain in RCS along with the addition of autonomous specific interlocks such as geofences.

A complete solution

Productivity

Machine: Propelling between holes and rows on a single bench, obstacle detection/avoidance, positioning, levelling, and drilling to target depth (corrected elevation) for vertical and angle drilling of blastholes.

The autonomous Pit Viper has been engineered for productivity, designed 34

A majority of the items captured in the safety, productivity and integration sections have direct contributions to efficiency. In addition, the autonomous operations center has monitoring and control components building efficiencies. Maintaining awareness of the fleet is accomplished through both actively selected or default drill mounted and controllable cameras as well as a unique Pit Viper f leet monitoring tool. This tool provides the responsible person the precise data needed for each autonomous Pit Viper operating in the fleet. Should a Pit Viper encounter issues, the person is alerted and can take action to include direct control utilizing the teleremote station at their desk. The Pit Viper with the integrated RCS platform will remain on the leading edge of autonomous drilling.

Dustin Penn and Tyler Berens

Automated drilling functions provide predictable, reliable, and repeatable drill operations where human operators Blasthole Drilling in Open Pit Mining

Talking Technically

Taking advantage of single-pass drilling The easy way to get more blastholes per day

40' Single-pass, (12.2 m) 50 MPa Rock*

90 2

40 ft

1

80 Overall production rate in metres/hr

Large rotary drills have been in use for years around the world in mining applications. In many open pit operations, these large drills were equipped with electric power and long towers for drilling benches in a single pass. Today, these features are being added to smaller equipment. Let’s look at the benefits of single-pass.

100

30 ft 30' Multi-pass, (9.1 m) 50 MPa Rock*

70 60 50

2 1

40

40' Single-pass, (12.2 m) 100 MPa Rock*

40 ft

30 ft

30 30' Multi-pass, (9.1 m) 100 MPa Rock*

20

Longer towers The drilling of large diameter holes, generally considered to be greater than 9 inches in diameter, is done predominantly with rotary blasthole drills. One of the reasons for this is that larger diameter tricone bits allow for large bearings to handle high pulldown forces to drill through hard rock quickly. These high pulldown loads require a heavy tower structure to transmit these pulldown forces to the drill bit. Further, this high pulldown must be offset by sufficient mass to keep the drill rig from lifting off the ground. The resulting rig is therefore quite heavy. With a heavy, durable rig already dictated by a large hole diameter, drill designers are able to take advantage of the large platform to offer longer towers capable of drilling benches in one pass. This often drives a change in structural design and supporting components such as undercarriages, but the basic rig envelope doesn’t change. Drilling a hole in one pass has many advantages.

10

* Compressive strength

0 0

2

4

6

8

10

12

14

Drill depth in metres

Fig 1. Comparison of single-pass and multi-pass drilling,  = Time lost for rod adding and rod removal,  = Lost productivity for multi-pass drilling.

Elimination of rod changing time Adding a rod may take 45 to 60 seconds depending on the size of the rig, and taking the rod back off may take 60 to 90 seconds. The extra time for removing a rod is due to the extra cycle required to lower the head to pick up the next rod. The effect of rod changing time is more dramatic in soft material, as shown in Fig 1. Surprisingly, it is the large metals mines that pioneered the use of single-pass drills, even though they may see limited productivity benefit. In extremely hard rock such as that encountered in taconite, the single-pass benefit might only be 3 percent. At the

other extreme would be very soft coal overburden. This material can be drilled with claw-type bits at rates of 400 meters/ hour or more. In this situation, a singlepass drill would yield an overall productivity gain of over 25 percent.

Simplified operation Even in situations where the productivity gain from eliminating rod changes is relatively small, there are benefits. Operators don’t have to worry about the rod changing operation, which consists of 10 actions to add a rod and 13 actions to remove a rod. Eliminating these tasks during each hole reduces the chance for errors such as crossthreading the tool joints on the drill

Fig 2. Single-pass Pit Viper rigs Rig

PV-235

PV-271

PV-311

PV-351

Hole range

152-251 mm (6-97⁄8")

171-270 mm (6¾-105 ⁄8")

229 - 311 mm (9 - 12 ¼")

270-406 mm (10 5 ⁄8 -16")

Single pass depth

12.2 m (40 ft)

16.8 m (55 ft)

19.8 m (65 ft)

19.8 m (65 ft)

Blasthole Drilling in Open Pit Mining 35

Talking Technically

Committed to superior productivity. The PV-271 is perfect for single-pass drilling of a 40 ft bench and has a maximum single-pass capacity of 55 ft (16.8 m).

rods or dropping a rod. Tasks such as changing a bit in the middle of the hole or reaming the hole to clear out cuttings are much simpler when you don’t have to add or remove rods. These factors could increase overall productivity by a few more percent.

build a unit to support a 70 meter hole in coal overburden. It may be possible, but you’d end up with a unit with a mast as long as a dragline boom. The expense of such a unit would probably never be recovered with the operating cost savings.

Less maintenance

Safety factors

The carousel and wrench systems used routinely in multiple-pass operation are high wear items due to the nature of their operation. While they may still be used on single-pass drills, especially for changing drill bits, they see a much lower duty cycle. As mentioned above, tight drill tool joints can be a problem. Improvements in breakout wrench systems have helped address these issues, but it is still common to see joints that can’t be broken by onboard wrench systems. Given the advantages above, why wouldn’t every drill be built as a singlepass? Obviously, it isn’t practical to

As towers grow in length, the supporting mainframe and undercarriage must grow as well. To maintain the structural life and reliability of smaller multiplepass units, proper safety factors must be used in the design. The result is a larger and more expensive machine than customers are willing to buy. An example would be the move from the DM-M2, a multiple-pass unit with 35-foot drill rods and a gross weight of about 57 tons, to the single-pass Pit Viper 271 for 16.7-meter holes. The Pit Viper 271 weighs in at around 80 tons. Many smaller rotary drills operate on slopes that could not be considered

36

firm and flat. While single-pass drills might be capable of operating on a minor slope (less than 10 percent), they will generally have a higher center of gravity than their multiple-pass equivalent, reducing the stability of the unit. This is often the operator’s perception as the unit may be capable of slopes that might be substantially more. However, many factors must be taken into account when determining whether to operate on a particular slope. Ground conditions are rarely a single plane. Instead, they are compound angles of widely varying rock size and type. Most operators err on the side of limiting the slope they will attempt to navigate. Thus, single-pass drills are viewed as being limited to flat benches only. As we say at Atlas Copco, we are committed to our customers’ superior productivity. We will continue to develop single-pass units for smaller diameter operations. While we have several smaller units already capable of singlepass (the DM25SP and DML-SP), they are rotary table drive units. They utilize lightweight towers on relatively small base units by locating the feed and rotation mechanisms towards the bottom of the tower. The drawback of this design is that rotation is accomplished through a rotary table drive that engages a fluted kelly bar, driven mechanically by drive pins. The kelly bars are very expensive due to the fluting milled into them, and if the material is abrasive, they wear quickly and result in high operating costs. However, in soft applications, they are a great option. We continue to develop topheaddrive units with longer towers. Adding to our fleet of large single-pass units, as outlined in Fig 2, we are testing the new Pit Viper 311. It is set up for single-pass drilling of 65 ft (19.8 m) holes, which is demanded by many metal mines. This unit will operate in the same diameter range as the DM-M3, which has 40-foot drill pipes and a 11.3-meter capability. We encourage our customers to look at single-pass drilling as it is one of the easiest ways to get more holes per day.

Brian Fox

Blasthole Drilling in Open Pit Mining

Talking Technically

Drilling at high altitudes Challenging locations Easily accessible, high grade ore is becoming scarce. To meet global mineral demand, mining companies must look to challenging locations for economically viable deposits. Naturally, this includes mountainous regions at high elevations. While some operations are already producing at altitudes exceeding 5,000 meters (16,405 ft), high elevations can have adverse effects on people and machinery starting as low as 1,500 m (4,922 ft).

Reduced density of air The primary problem with high altitude is the decreased mass density of air. To understand this concept, you must first look at the composition of air. Air molecules consist of nitrogen (78%), oxygen (21%) and other gases, and have a given molecular weight. As gravity pulls the air towards the ground, these air molecules are subject to the additional weight of all the molecules above. This additional weight means the air pressure is highest at sea level, and diminishes with increases in elevation. This is much like water pressure in a swimming pool. At the surface, the water pressure is relatively low. As you dive lower, the pressure increases due to the weight of the water above. The reduced mass density of air poses two problems. First, the air molecules and their associated density are what carry the drill cuttings out of the hole. If there are fewer molecules per cubic foot of air, there is less carrying capacity. Second, while the oxygen content is the same (21%) at sea level at high elevations, there are fewer molecules available and therefore less total oxygen available for humans or engines.

The entrance to the Collahuasi mine is located 3800 meter above sea level.

Altitude and temperature It must be noted that temperature and humidity also factor into the density of air. Humidity has little impact and, counter-intuitively, actually reduces the air pressure as moisture increases. This is because water vapor (in gas state, not liquid) is lighter than the nitrogen and oxygen molecules it is displacing. Temperature, however, has a significant effect. Air, like most substances, expands when heated and contracts when it cools. The molecules move further apart with an increase in heat, and thus reduce the density of the air. The majority of heat carried by air molecules is via conduction from the earth, which is heated throughout the day by the sun’s rays. The air temperature becomes colder at a fairly uniform rate as it moves further from the heat source, and there are fewer air molecules to transfer heat at high altitudes. This is called the environmental lapse rate. The normal lapse rate is 3.5°F (1.94°C) per 1,000 feet (304 m) of altitude, though it can range from 3°F (1.66°C) for saturated air (100% humidity) to 5.5°F (3.05°C) for dry

air. Therefore, 59°F (15°C) at sea level (which is often referred to as the standardized condition) would drop to 7°F (-14°C) at 15,000 ft (4,572 m). The altitude has now created a situation where cold weather provisions are needed for proper operation of the drill.

Air compressors & bailing At sea level, an air compressor will compress a certain volume of air at atmospheric pressure to a higher pressure, yet lower volume. It is often misstated that compressors produce less CFM at high altitude. As an example, let’s start with a 1,900 cubic feet per minute (CFM) compressor rotary drilling at sea level. The compressor rating is the intake CFM, meaning it can pull 1,900 cubic feet of air into the compressor every minute. What comes out the outlet of the compressor is determined by the downstream restriction, which we’ll assume are the nozzles of a tricone bit. If small nozzles are used, or the bit becomes plugged, the pressure will increase back to the compressor, up to the maximum pressure allowed by the system (e.g. 110 PSI). The concept

Blasthole Drilling in Open Pit Mining 37

Talking Technically

When moving from sea level up to high altitudes the density of air will decrease, and the temperature will drop at a fairly uniform rate.

is similar to water running through a garden hose. Running unrestricted, a large volume of water comes out, but at a low pressure. If you put your thumb over the end of the hose, the pressure will increase but the volume will be reduced. In our example, if the nozzles are sized properly, the pressure at the bit might be 60 PSI. At this lower pressure, the volume would be higher than at 110 PSI, but still much lower than the intake volume. As the air moves through the bit and up the hole, the pressure will eventually drop to atmospheric pressure again, at a high volume. At 15,000 ft (4,572 m), the same compressor is still taking in 1,900 cubic feet of air per minute. However, the number of molecules of air is reduced by approximately 42%, calculated by comparing the air pressure at sea level

(14.7 PSI or 101 kPa) to the pressure at elevation (8.6 PSI or 59 kPa). To compensate for the lower density, correction factors are used to calculate the effective, not actual, intake CFM required to produce the same performance as at sea level. In this case, the reduced air pressure effectively cuts the compressor to an equivalent intake capacity of 1106 CFM (assuming the same temperature as sea level). Taking into account the lower temperature and corresponding increase in density, the intake capacity would move up to 1,221 CFM at 7°F (-14°C). To determine how much air is required, a calculation of uphole velocity is required. Uphole velocity is calculated from the intake air volume and the annular area, which is the gap between the wall of the hole and the drill rod.

A minimum uphole velocity is often stated as 5,000 ft/min but in reality is affected by the density, size and shape of the chips, and factors such as the pressure of cuttings or water in the hole and the condition of the borehole wall. Using a Pit Viper 271 as an example, the table below shows a comparison at various elevations. At sea level, 1900 CFM for a 10-⅝” bit with 7-⅝” rod works well, even as the rod wears down. At high altitude, the large reduction in air density requires either a larger compressor (2600 CFM in the example) or a larger (10-⅝”) diameter drill rod. The preferred option is a larger compressor, as using larger rods cuts the clearance between the wall of the hole and the rod to such a small gap that larger cuttings must be reground to a smaller size before exiting the hole, thus accelerating bit wear. Going to a smaller diameter bit will improve uphole velocity as well, though this is not always feasible given the blasting requirements.

Power drain Diesel engines face considerable difficulty at high altitude as they rely on the oxygen in the air for proper combustion. Engines have varying altitude limits and power de-rate curves. Manufacturers are able to maintain full power to the altitude rating by changing the engine timing, turbocharger configuration and compression ratios. This altitude rating is the point where horsepower begins to decrease. As a rule of thumb a diesel engine will de-rate

Uphole Velocities Compressor At Sea Level/15° C (59° F)

At 15 000 ft/ –14° C (7° F)

Rating: 1 900 cfm

Rating: 2 600 cfm

Rating: 1 900 cfm

Rating 2 600 cfm

Hole Ø (in)

Drill Rod Ø (in)

Effective Vol. 1 900 cfm

Effective Vol. 2 600 cfm

Effective Vol. 1 221 cfm

Effective Vol. 1 670 cfm

10 ⁵⁄₈

7 5⁄8

6 434 ft/min

8 804 ft/min

4 087 ft/min

5 592 ft/min

10 ⁵⁄₈

8 ⁵⁄₈

9 149 ft/min

12 520 ft/min

5 812 ft/min

7 953 ft/min

9 ⁷⁄₈

7 5⁄8

8 946 ft/min

12 242 ft/min

5 682 ft/min

7 776 ft/min

9 ⁷⁄₈

8 ⁵⁄₈

15 232 ft/min

20 855 ft/min

9 675 ft/min

13 240 ft/min

1 900 cfm = 53.8 m3/min 1 000 ft = 304 m 5 000 ft/min = 25.4 m/s

Comparison of compressor performance at high altitude vs sea level and subsequent effect on uphole velocity in rotary drilling using a Pit Viper 271 drill rig.

38

Blasthole Drilling in Open Pit Mining

Talking Technically

its output by 3% per 1,000 ft (304 m) above altitude limit. For example, an 800 HP diesel engine might have an altitude limit of 8,000 ft (2,438 m). At 15,000 ft (4,572 m), the power would be 21% less, or 632 HP. At full power assuming maximum compressor and rotary head power, this unit would approach 90% load, or 720 HP. If this unit operated with mechanical or hydraulic drive systems that do not de-rate, there would be insufficient power to operate at this elevation. However, because the air compressor is working with lower density air, its power requirement is reduced by 1.5% per 1,000 ft (304 m). The 1,900 CFM compressor itself requires approximately 430 HP to provide full flow and pressure. At 15,000 ft (4,572 m), the load drops by 22.5% to 333 HP, effectively cutting the total load from 720 HP to 623 HP, safely below the de-rated power. For best results, it is preferable to go with a larger displacement engine with a higher output to offset the reduction due to altitude. However, it is not always possible to provide larger engines as the drills are sized to handle a particular size engine from the beginning and space is not available. Another alternative is electric power. Electric motors do not rely on combustion for power, and are not subject to power loss due to lack of oxygen. However, there are two issues which can impact the operation of electrical components such as motors, starters and transformers. One is the decreased cooling capacity at altitude. Higher capacity components may need to be specified to achieve the same rating as lower altitudes, though the cold air at altitude generally ensures standard components do not overheat. The second issue is that lower air density reduces the di-electrical strength of air gaps in components, thus reducing the insulation capacity of these components and increasing the risk of electrical breakdown, or flashover. At extremely high elevations, special electrical components may be required. The decision to go with electric power has to consider other factors like how electricity is generated and the demand for mobility of the rig. In

Atmospheric Pressure vs. Altitude 110 100 90 80 70 60 50 40 30 20 10 -10

Air Mass Density vs. Altitude

Atmospheric pressure (kPa)

4 800 m

50 %

15 750 ft

Computed for 15 deg. C and 0% humidity

2 000 5 000

4 000 10 000

6 000 15 000

8 000 20 000

Altitude (m) Altitude (ft)

Sea level

100 %

The primary problem with high altitudes is the decreased mass density of air. There are fewer molecules for carrying drill cuttings out of the hole and less oxygen available for humans and engines.

remote areas, the only alternative to produce electricity might be by diesel powered generators. In such a case, the power generation will also suffer from the power de-rating at high altitude, and a diesel powered rig can still be the best alternative if it can be configured to meet the required performance. Electric power may offer higher capacity, but this might be offset by the mobility and higher utilization of a diesel powered rig.

Cooling requirements With fewer air molecules available, the ability to remove heat from the engine, compressor and hydraulic system is reduced. Limiting Ambient Temperature (LAT) is the temperature at which the cooling system becomes marginal; the design standard is 125°F (52°C) rating. For the engine and compressor, cooling is not a problem as they are also de-rating; the LAT essentially remains the same. As the hydraulic oil density does not change, the LAT rating is reduced to approximately 90°F (32°C) at 15,000 ft (304 m), though temperatures at this altitude are unlikely to approach that level.

Human impact Aside from the engine, compressor and cooling systems, there is little impact on the drill simply from the altitude. Excluding the extremely cold

temperatures that may be present, structures and gearboxes perform as if at sea level. Hydraulic components are unaffected except for the charging of pumps, which may require a change in the charging circuit. An example would be using a pressurized hydraulic tank. The biggest impact of high altitude is on the operators and technicians working on the drills. The human body compensates for the decreased amount of oxygen with higher respiratory and heart rates along with a gradual increase in red blood cells that carry oxygen (known as acclimatization). Every person is different, and many can contract acute mountain sickness (AMS) beginning at 8,000 ft (2,438 m). AMS symptoms are similar to a hangover, but this is minor compared to much more dangerous problems such as cerebral and pulmonar y edema. Mining companies are very careful when it comes to ensuring the safety of their employees and contractors. Examination by medical experts is required before allowing work in these tough conditions, and full onsite medical services are available to deal with problems. Ultimately, autonomous drilling will play a significant role as mining companies push to higher elevations.

By Brian Fox

Blasthole Drilling in Open Pit Mining 39

Talking Technically

In 2007, Barrick Gold installed the world's highest-situated wind turbine at the Veladero mine at nearly 4,200 m elevation.

40

Blasthole Drilling in Open Pit Mining

Talking Technically

Drilling in Arctic conditions Coping with climatic extremes The spread of mining to inhospitable parts of Mother Earth has posed a major challenge for mining equipment design engineers in terms of both basic machine functions and operator well being. Operation at high latitude or high altitude requires a significant degree of redesign. Available coal and mineral resource geography has intensified, first with exploration and then mining activity, in the Arctic and sub-Arctic central continental regions of North America and Asia. In parallel the ability to build equipment that can operate economically at temperatures around -55°C has become increasingly important. Similarly, the development of mines at high altitudes requires machines that can cope with low atmospheric pressure as well as low temperature.

The Russian experience For rotary drill rigs the key base materials adversely affected by low temperature operation are steel, rubber and lubricants. • At lower ambient operating temperatures steel becomes brittle, creating possible earlier fatigue failures. For heavy equipment designers, the task is to select steel with proper material properties, to reduce the load or to reduce the loading cycles. Through the combination of the three factors, structural integrity can be equalled to equipment running in non-arctic conditions.

Exposure and constant ground contact subject the crawler undercarriage to particular abuse in low temperature, icy conditions, requiring careful selection of materials. Some applications may require heating the drive elements to keep them working.

• With any rotating equipment, seals and hoses are used to retain fluids. Like steel, the newer generation synthetics lose f lexibility, becoming brittle. With arctic conditions, the key is again through material selection to keep equipment doing its primary function without the aid of artificial heat sources. In an arctic application the use of natural rubber or silicon is better than synthetics. • To maintain acceptable component life in arctic conditions effective lubrication is essential. Typically this will require using the standard additives with a base lubricant that will flow at the ambient temperatures and at the viscosities specified for the application. Beyond making necessary changes to base materials, subsystem redesign may be required to meet the low

temperature challenge. Engineers must decide if the material can be changed, heat be added or in some cases the part be eliminated to achieve 5,000 to 6,000 operational hours per year. Exposure and constant ground contact subject the crawler undercarriage to particular abuse in low temperature, icy conditions. Many components either rotate or articulate (rollers, idlers, drive sprockets and track chains). Again the driver is to upgrade the base material, steel and rubber, where necessary. Some applications may require heating the drive elements to keep seals soft and pliable. Similarly, for a diesel engine powering the rotary rig in these conditions, special attention must be given to start-up and lubrication. Atlas Copco has designed a series of heater packages for lubricants, the engine block and batteries. All these packages are

Blasthole Drilling in Open Pit Mining 41

Talking Technically

powered by 110, 240 or 380 V AC electricity provided by the mine electrical grid or a diesel generator. If getting electrical power to the drill is impossible, a diesel-powered block heater is another option available. Likewise if low ambient fuel is not available use of 24 V DC fuel heaters is yet another option available. Lubrication systems pumping grease over long distances can be impossible, and it may be best to redesign with a component that has impregnated oil bushings or closed bearings. To prevent the pump from cavitating, the lubricant will either have to be heated or replaced by a special blend that maintains viscosity through the ambient temperature range. Dust suppression is most difficult in low ambient climates. The synthetic rubber normally used in dry dust collectors becomes brittle in extreme cold, and articulated components such as hoses and dust curtains will fail. If the drop out chute does not close properly the system fails to back flush. Also moisture entering the collector will freeze when it enters the cold dust collector chamber. Vibrators can be used to prevent material collecting on the dust collector body. Another option under development is a wet dust control system. To keep the system from freezing is a design challenge. In this case short hose connections with diesel fired pre-heaters create enough energy to keep the system in operation.The benefit with wet systems is the reduced number of moving parts. Given that the time limit for human exposure to very cold air is 15 minutes, the cab for artic rigs must be big enough for two operators and their cold weather clothing. Additional insulation, heating and defrosting capability are also essential. The marriage of low temperature solutions and advanced technology on Atlas Copco Drilling Solutions rotary blasthole drills has been successful. Today over 150 Drillmaster and Pit Viper class rigs work in coal, gold, copper, diamond and iron mines where temperatures can drop below -40C.

John Stinson 42

Atlas Copco has designed a series of heater packages for lubricants, the engine block and batteries.

Watermist closed.

Watermist open.

Proheat closed.

Proheat open.

Wiggins closed.

Wiggins open.

Blasthole Drilling in Open Pit Mining

Talking Technically

Tricone rotary blasthole drilling Rotary tricone bit elements Rotary tricone bits consist of several basic parts: Three “roller cones” with the bit ‘cutting structure’ (tungsten carbide inserts or milled steel teeth) on their external surfaces; “bearing races” machined inside each “cone bore”; three sets of bearing elements consisting of small “inner” rollers, ball bearings, and large “outer” rollers; and three “lugs”, each having inner, ball, and outer bearing races that match the cone bore races and hold the different bearing elements.

Rotary tricone bit fundamentals Rotary tricone bits consist of several basic parts: • Three “roller cones” that hold the cutting structure on their external surface, and the bearings in their interior • The “cutting structure” consisting of either Tungsten Carbide Insert teeth, or milled steel teeth. • Three “lugs”, each of which has the bearing “journals” which match up with the cone bearing “bore”. • Inner and outer roller bearing elements. • Ball bearing elements. These basic parts are then assembled into bit thirds, and three ‘thirds’ are then assembled into a “tricone” (three cone) bit. Once completely assembled into a finished bit, the bit “pin connection” is threaded with the appropriate connection size and type for the bit diameter. The figure at right illustrates the assembled components of a tricone bit and presents a ‘cut away’ of one lug/ cone assembly to show the internal component arrangement. Note that this figure shows air passages from the bit interior into the bit bearing areas. This is an “air bearing”

Elements of a rock bit.

bit. Other types of bearing configurations are “open” (or fluid) bearing, and “sealed” bearing. “Open” bearings do not have any internal air passages, and the back of the cones are ‘open’ to the external drilling environment. “Sealed” bearings are completely enclosed, with no internal air passages. The bearings are sealed off from the external drilling environment, and are filled with pressurized grease.

Rock breakage Contrary to popular opinion, rotary tricone bits do not drill by “crushing” rock. Instead, they actually drill by a mechanism called “spalling”. A European gentleman named Hertz originally defined this method of rock breakage back in the 1880’s. If a force is applied to an “indenter” in contact with a rock

surface, stress fields are set up under that indenter. As the loading force on the indenter is increased, the stress fields extend outward and downward from the point of contact and loading. The applied load creates fractures (cracks) that propogate along the stress field vectors, seeking a “free surface”. When these stress vectors find the free surface, the crack is completed, and the rock above the stress vector breaks free. A rock “chip” or “cutting” is created, and must now be removed. Because tricone bits apply this force to several inserts simultaneously on each cone, the cones must constantly be rotated to new “indenting” positions in order to advance the hole. It would do no good to simply continue to apply weight to the bit without rotation. Nothing would happen. The bit must be rotated to bring new teeth into position for loading and rock breakage.

Blasthole Drilling in Open Pit Mining 43

Talking Technically

Drillhole cleaning / cuttings evacuation

Air circulation through nozzles and bearings.

44

Once the “cuttings” are created, they must be evacuated. If the cuttings are not removed from the hole, the bit will be ‘eroded’ by the abrasiveness of the rock chips, and the teeth will quickly wear down and/or fall out, rendering the bit ineffective. In blasthole drilling, hole cleaning is done with compressed air. The rotary bit is either attached directly to the “drill pipe”, or one of a number of other drilling accessories, (bit adaptor subs, bit stabilizers) are used to attach the rotary bit to the drill pipe. The exact attachment method depends upon the drilling situation. In any case, a large volume of compressed air is directed down through the drill pipe (also called the drill string) into the bit. The flow of compressed air is intentionally restricted at the tricone bit by the use of “jet nozzles”, in order to create ‘back pressure” and a “pressure drop” through the bit. This ‘back pressure” forces air into the bearings of an “air bearing” bit, to keep the bearings cool and clean, and to prevent contamination from entering the bit. Secoroc wants to achieve an actual pressure inside the bit of 45 psi (3.1 bar) or higher. This will direct from 15% to 25% of the air into the bearings for bearing maintenance, while the remaining majority of the air creates a “jet blast” against the face of the hole to blow newly formed cuttings away from the bit. The following figure shows the bit’s internal air path in yellow. Jet nozzles are shown in purple. Rock density (specific gravity) varies greatly, depending on what material is being drilled. Coal for instance has a SG of around 1.6, while some iron ores have a SG greater than 3.8. Most rock we drill has an in situ SG of between 2.4 and 2.8. If there is a lot of natural ground water, this can wet the cuttings, increasing the cuttings SG by about 0.1 SG. Secoroc recommends a minimum air “Bailing Velocity” of 5,000 - 7,000 feet/minute (1524 - 2134 meters/minute) for light and dry materials, and 7,000 9,000 feet/minute (2134 - 2744 meters/ minute) for rock materials that are wet or have a high density.

Drilling parameters Secoroc tricone bits generally conform to the IADC rock type classifications. IADC is the International Association of Drilling Contractors, who set many “standards” and “conventions” for the general drilling industry. Secoroc has adapted certain IADC concepts to its tricone bits. Tungsten Carbide Insert bits fall into five IADC classes: • 4-1 to 4-4 - very soft to soft • 5-1 to 5-4 - soft to medium • 6-1 to 6-4 - medium to medium hard • 7-1 to 7-4 - hard to very hard • 8-1 to 8-4 - very hard to extremely hard In general, decades of bit manufacturing, and product development and application experience gives us the following operating guidelines: For 4-1 to 4-4 IADC type bits: • 50 to 150 RPM • 1000 to 5000 pounds of applied load per inch of bit diameter For 5-1 to 5-4 IADC type bits: • 50 to 150 RPM • 3,000 to 6,500 pounds of applied load per inch of bit diameter For 6-1 to 6-4 IADC type bits: • 50 to 120 RPM • 4,000 to 7,000 pounds of applied load per inch of bit diameter For 7-1 to 7-4 IADC type bits: • 50 to 90 RPM • 4,000 - 8,000 pounds of applied load per inch of bit diameter For 8-1 to 8-3 IADC type bits: • 40 to 80 RPM • 6,000 - 9,000 pounds of applied load per inch of bit diameter As the rock gets harder, it is adviseable to apply slower RPM. As more load is applied to a bit it is adviseable to apply slower RPM. “Strong” rocks may need ‘time’ for the indenting teeth to create sufficient stress in the rock fabric to cause it to crack, and the crack propagate. Thus, in ‘strong’ or ‘hard’ rock it is suggested that lower RPM is used. “Weak” rock does not need as much time to react to the indenting teeth. Higher RPM can be used effectively in “softer” ground. These are general guidelines, and are intended as suggestions only. Every rock type is different, and every specific Blasthole Drilling in Open Pit Mining

Talking Technically

IADC vs. Rock UCS 48000

8-1 to 8-4

70000

IADC Class

36000

7-1 to 7-4

56000

22000

6-1 to 6-4

42000

6000

5-1 to 5-4

28000

1000

4-1 to 4-4

10000

0

10000

20000

30000

40000

50000

60000

70000

Rock UCS (PSI)

IADC vs. Rock UCS Chart showing comparison of IADC classifications to rock hardness.

rock type exhibits a wide variation in mechanical properties at an individual site. Individual mines should determine optimum operating parameters for each rock type and drill type at that specific site.

The value of a bit What is the “value” of a bit? What determines how ‘good’ a bit is? Ask around, and you will probably get one of these four answers to the question of ‘value’: • Low price • Long service life • High penetration rate • Low operating cost Secoroc believes the highest “value” a tricone rock bit can have is “low operating

cost”. Considering that the cost of owning and operating a modern rotary drill rig can approach US$400 or more, bit performance needs to be judged on what the total cost of operating the drill is. This then, goes hand in hand with a high penetration rate, and is accompanied by a ‘good’ service life. Consider this example: • Drill operating cost per hour = US$300 • Penetration rate of Competitors bits = 30 meters/hour • Penetration rate of Secoroc bits = 45 meters/hour • Hole depth = 15 meters The “Operating Cost per Meter” is calculated by: • OC/m = Drill Operating Cost / Penetration Rate

Performance comparison for distance, of two bit types, over time.

Thus, it is easy to see that for a 15 meter drilled depth hole: • Competitors Operating Cost / meter is US$300 / 30 = US$10.00 • Secorocs Operating Cost / meter is US$300 / 45 = US$6.66 The faster drilling Secoroc bit saves the mining company US$3.37 for every meter drilled. That is value.

Bit record keeping Without keeping track of bit performance, there can be no way to measure one bit type against another, and one bit supplier against their competition. Secoroc can provide the templates for two types of “Bit Record Book” to record bit performance. Compilation of product performance histories creates a valuable tool for the sales person and bit manufacturer. Different bits can be compared at a minesite. Performance of the same bit at different minesites can be compared. How does one drill type compare against another drill type? If a new mine is being opened, you need to have an idea of what products to offer, and what performance can be expected. Secoroc has a global product performance database available in Lotus Notes. Product performance from mines around the world can be compared. Sales people easily generate a variety of reports for their monthly business reviews and sales calls. Below is an example of a report generated by Perform v6, for two bit types compared over a five month period:

Clarence Zink

Blasthole Drilling in Open Pit Mining 45

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46

Blasthole Drilling in Open Pit Mining

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Optimizing the rotary drill string Money in the bank In rotary drilling, the careful selection of every drill string component is vital to achieve accurate holes, optimal rock fragmentation and operational efficiency – parameters which affect total operational costs.

Close attention When developing a rotary drilling system, most of the attention is usually given to the drill rig, the capital equipment that requires significant investment and hence a planned payback. The second priority in the system tends to be choice of rotary tricone drill bit – the Tricone. However, to utilize the full power and capacity of the rig and the bit, and at the same time increase service life and productivity, consideration should also be given to the entire drill string. The optimal drill string includes a shock absorber at the top, a rotary deck bushing to centralize the drill string as it passes through the deck of the rig, strong and straight drill pipes and finally a hole stabilizing roller stabili-zer or bit sub-adaptor to optimize the performance. Giving the necessary attention to every part of the drill string will lead to the lowest total operating costs in rock excavation and fragmentation.

The rotary drill string The primary purpose of the drill string is to transmit the rotational torque and weight from the power source – the rotary head of the rig – to the rock breaking drill bit. As for every rock drilling method, the power must be transmitted as efficiently as possible, and return as few vibrations as possible, as these cause unnecessary wear on the rig and reduce penetration rates. When selecting components for the drill string, attention must be given to the different roles of the support tools in the string. The aim can be to:

Giving the necessary attention to the drill string components will pave the way for quality drilling and lower total operating costs.

• reduce wear and tear on the drill rig • absorb damaging vibrations travelling back up the drill string • improve transmission of energy from the rotary head to drill bit • centralize the drill bit within the hole • longer bit life • reduce friction as the drill string passes through the drill rig deck • stabilize the hole wall to prevent hole caving • increase penetration rates and lower drilling costs • achieve blast hole accuracy for improved blasting efficiency • improve the end result – the fragmentation of the blasted rock.

Shock absorber At the very top of the drill string – between the rotary head and drill pipe – a shock absorber is commonly used. As the name indicates, the intention of this tool is to reduce the negative effects of harmful vibrations that travel back up the string as a result of the drilling process. The benefits of using a shock absorber include: • improved torque control • increased drilling penetration rates • better drill rig availability and extended drill rig drive head and mast life • longer service life of drill bits

Blasthole Drilling in Open Pit Mining 47

Talking Technically

Smoothdrive™ shock absorbing sub

Square drive flange method

Welded strap method

Smoothdrill™ shock absorbing sub

B A D C E

Threadsaver sub

Full length repairable Teamalloy™ body drill pipe (box-box optional)

OD ID

Centeroll™ rotary deck bushing (repairable)

WLS

EZ-Drill™ roller stabilizer

Duralloy™ bit sub adaptor Duralloyª bit sub

Secoroc Tricone bits

The optimal drill string includes a shock absorber, a rotary deck bushing, strong and straight drill pipes and finally a hole stabilizing roller or bit sub-adaptor.

Deck bushing To guide the drill string and reduce the risk of wobbling, a rotary deck bushing is utilized at the drill rig deck opening. The deck bushing guides the pipes to prevent reduction of rotary head torque and assists with the final straightness of the hole. The deck bushing contains an outer housing with a top flange that allows it to fit perfectly into the deck opening. A series of roller bearings allow the inner sleeve to rotate with the drill string. Wear of the deck bushing occurs primarily on the inner sleeve as cuttings are blown upwards, between the drill pipe and the inner sleeve.

while still achieving an acceptable life of the Tricone bit. The use of a strong and straight alloy drill pipe is one of the best ways of preventing wobbling of the drill string and hole deviation. Drill pipe is subjected to a severe and abrasive environment, due to the rapid evacuation of drilling cuttings through the annulus of the hole, causing a sandblasting effect on the drill pipes. It is logical, therefore, to utilize only the best alloy steel for both the threaded connections and the body of the drill pipe. Special wear protection material is applied to the most critical areas of erosion at the bottom of the drill pipe. The drill pipes can, in most cases, be refurbished to prolong service life.

Drill pipe

Bit sub adaptor or stabilizer

The role of the drill pipe is to transfer sufficient amounts of rotational torque and weight to the drill bit. The goal is to establish an optimal rate of penetration

To connect the bit to the drill pipe, a wearprotected bit sub adaptor is generally used when the rock formation is relatively competent, and not in need

48

of stabilization within the hole. In some softer, fractured rock formations, it is worthwhile to consider the use of a stabilizer as an alternative. The roller stabilizer contains three roller assemblies which provide support against the hole walls, serving to both guide the drill bit in a straight direction and pack the wall of the hole to prevent caving in. The use of either straight or spiral-bladed stabilizers is strongly discouraged as this causes excessive friction when these blades are at full gauge diameter, while they also lose gauge diameter rapidly rendering them virtually useless as a stabilizer after only a few shifts. In addition, the spiral-bladed stabilizer slows down the evacuation of the cuttings. So, to achieve improved hole straightness, hole wall integrity, and at the same time increase the effective life of the stabilizer, only stabilizers with rollers fitted with cemented carbide inserts are recommended. All in all, when you consider the significant amount of capital invested in a rotary blasthole drill rig and the annual investments in Tricone drill bits, the selection of the best quality rotary drill string tools that are suited to the application, is critical to the eventual success of the drilling program. The rotary drill string tools should not just be considered as mere support tools, but rather as an essential, integrated part of the total rotary drilling system. The following basic criteria should be considered when deciding which rotary drill string tools will best optimize overall drilling performance and cost effectiveness: • are quality materials and innovative design used to address specific drilling problems? • can the tools be refurbished for an economical second run? • does the supplier of the tools offer application and follow-up service? In conclusion, straight blast holes drilled exactly to the pre-planned hole bottom positions, pave the way for lower total operating costs, taking into account the entire process – drilling, blasting, secondary breaking, loading, haulage and crushing/screening.

Rick Meyer

Blasthole Drilling in Open Pit Mining

Talking Technically

Increased productivity with DTH drilling Cutaway section of Secoroc COP 64 Gold.

DTH growing in popularity The DTH drilling method is growing even further in popularity, with increases in all application segments, including blasthole, water well, foundation, oil & gas, cooling systems and drilling for heat exchange pumps. DTH competes favourably with rotary drilling in open pit mines, mainly thanks to increased productivity and flexibility. Open pit mining has adopted smaller holes where rotary drilling has either been replaced by DTH, or where DTH has been introduced to create a better finish to the pit wall, as the method is also perfect for pre-splitting and smooth blasting, which avoids back-cracking. DTH drilling offers increased productivity, and is fa-voured by contractors for production drilling. In larger quarries, the optimum hole size is 110-171 mm. With today’s demands for strict hole control for safe blasting in populated areas, DTH drilling is a popular choice among quarry operators.

in joints; and efficient energy transmission, with the piston striking directly on the bit. The COP 34-64 series of hammers was introduced from 1992, and immediately became the benchmark for productivity within DTH drilling. Over the years, the increase in average drilling pressure, from 17 bar to a current market standard of 30 bar, has improved hammer performance, and productivity has increased proportionally to air pressure. The introduction of the Atlas Copco ADS and SDE series of high-performance, highpressure DTH rigs gave another boost

to the sales of hammers. The flexibility, productivity and manoeuvrability of these rigs, when equipped with a COP hammer, make them the most productive combination on the market today.

COP Gold series The increase in drilling pressure also had some negative impact on the internal components of the DTH hammer, as the increased stress promoted the risk of premature failures. So, in 1998, Atlas Copco Secoroc decided on a longterm strategy to improve reliability,

Quality holes In the hole range 100-254 mm, DTH drilling is the dominant drilling method today. The main features of DTH drilling in this hole range are: excellent hole straightness within 1.5% deviation without guiding equipment; good hole cleaning, with plenty of air for hole cleaning from the hammer; good hole quality, with smooth and even hole walls for easy charging of explosives; deephole drilling capacity, with constant penetration and no energy losses

New Secoroc hammer and bit ready for action on an Atlas Copco drill rig.

Blasthole Drilling in Open Pit Mining 49

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COP 64.2 steel COP 64 Gold steel Improvement

Yield point ReL(Mpa) Breaking strength Rm(Mpa) Hardness (HRc)

700 1000 32

1400 1950 42

100% 95% 31%

Table 1 reveals not only that the yield point for the new steel grade is twice as high, but also that breaking strength has been almost doubled.

Table 1 Comparison of COP 64.2 and COP 64 Gold steel.

while retaining the benchmark status of the COP DTH hammers. Stage One of this strategy was the development of the second generation six-inch hammer, COP 64.2, introduced in October, 2000, which incorporated newly-designed steel disc spring and lower buffer. Performance was vastly improved, thanks to a drastic reduction in the number of internal failures. It was also possible to rebuild the hammer without diminishing its performance, making it even more attractive. Stage Two was the introduction of the third generation COP 64 hammer, COP 64 Gold, which was unveiled in August, 2001. This version offers sustained performance and improved longevity of the external parts. The COP 64.2 resolved internal component reliability, while the COP 64 Gold has experienced a dramatic drop in the number of cylinder failures. COP 64 Gold also boasts improved sustainable efficiency, maintaining an average of 96% of original performance throughout its service life, which is a further improvement on COP 64.2.

Durability improvements, thanks to the higher tensile strength of the new steel grade, are especially noticeable when the cylinder approaches minimum thickness limits. COP 64 Gold enjoys a greater durability margin than its predecessor. The high demand for COP 64 Gold hammers, particularly in applications where performance and reliability are major considerations, has led Atlas Copco Secoroc to add the COP 54 Gold and COP 44 Gold to this increasingly successful range. In July 2004 COP 54 Gold was released with the same features as the COP 64 Gold and improved performance thanks to a heavier and modified piston and a 12 spline bit shank. The COP 44 Gold was released in Q3 2009. As the other hammers in the Gold Series It will have improved longevity of the external parts thanks to the “Gold” cylinder. Internally it is improved with a heavier piston that will increase the performance and with modified buffers and a steel disc spring the lifetime of internal parts is

extended. And finally a new 12 spline bit shank with 19% more area than DHD340A minimize shank failures in soft or unconsolidated rock.

Hammer cylinder The new cylinder has been redesigned in a number of important ways. COP Gold boasts a cylinder made of low alloy wrought and toughened steel, a new grade with a higher combined Molybdenum and Vanadium content (4.8%) than its predecessor. The result is greater impact strength and higher wear and temperature resistance. All in all, this means greater resistance to breakage, impact, temperature and wear for the new hammer cylinder. Thanks to the new steel grade, cylinder properties have been greatly improved. Wear has been reduced, both internally and externally. Cuttings and moving parts no longer cause the problems they once did. In effect, the service life of the cylinder has been extended considerably.

Rebuilding With the introduction of COP Gold Series, hammer life will increase substantially. Less internal and external wear, together with a reduced minimum cylinder wear limit, are key contributing factors. As a rule of thumb: If the hammer has reach it’s external wear limits before 5000 drill meters use an

Secoroc COP 54 Gold.

50

Blasthole Drilling in Open Pit Mining

Talking Technically

Total improvement Due to wear resistance Due to wear limit change Due to less cylinder failure

Increase in service life of COP 64 Gold, which has a 50% longer life than its predecesssor.

Economy Kit and rebuild the hammer, between 5000 and 10 000 drill meters consider to rebuild the hammer and with more than 10 000 drill meters the internal parts could be subject to fatigue failures. Ultimately, this means customers can look forward to increased drill rig availability. The sum total of these improvements shows COP Gold Series to have more than 50% greater service life, in abrasive rock conditions, than its predecessors.The customer benefits from lower cost/metre drilled, thanks to less downtime and greater abrasion resistance, and 30-50% longer life of external parts. Higher availability results from less breakage in the threads of top sub and chuck-ends of the cylinder, and

there are fewer stoppages for service and maintenance. Improved penetration rate and higher efficiency are a result of reduced friction of the piston, and a greater life cycle penetration rate is the overall reward. To sum up, the customer can drill more holes per hammer than previously.

Applications COP Gold Series is high-pressure hammers, where performance is related to air pressure. A lower limit of 12 bar for deep hole applications is a good rule of thumb. In abrasive formations, performance will be up to 15-50% better than old

COP STD, in what is an ideal application for COP Gold hammers. In soft unconsolidated rock drilling, the 12-spline chuck concept and the improved durability make COP Gold the perfect hammer. High pressure yields higher productivity, and drilling pressures of 28-30 bar are not unusual. The COP Gold hammer concept offers customers a tool to meet the most demanding requirements with sustained productivity.

Leif Larsson

16 000 14 000

Drill metres

12 000 10 000 New Material Old Material

8 000 6 000 4 000 2 000 0 146 145 144 143 142 141 140 139 138 137 136 135 134 133 132 131 130 129 128

Cylinder OD (mm)

Results of comparative tests with COP 64.2 and COP 64 Gold. The COP 64 Gold drilled 50% further.

Blasthole Drilling in Open Pit Mining 51

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52

Blasthole Drilling in Open Pit Mining

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Selecting the right DTH drilling tools Covering every application Atlas Copco Secoroc now has the most comprehensive range of DTH hammers, bits, and related equipment of any supplier in the world, backed by the strongest support network in the industry. Whether the call is for reliable hammers to keep investment to a minimum, or for the highest productivity to ensure maximum rig output, Atlas Copco Secoroc has the solution. The company is the only manufacturer to offer both first and second choice solutions in almost all typical DTH applications on a price vs performance basis. For premium performance and advanced technology, QLX (replacing TD) and COP Gold hammers are offered. For an optimum blend of features and cost, the QL (Quantum Leap) can be the solution for high reliability at economical price. QLX, COP Gold, and QL hammers are also energy efficient, consuming less fuel and with lower energy cost per drilled metre than other DTH hammers. This wide choice of DTH drilling tools is backed by a reliable network of distributors and customer centres that offer a complete range of parts, service and support.

Quarrying application.

Relevant applications Quarrying Companies producing in non-abrasive rock formations should consider hammers such as Secoroc QL series, a time-tested and field-proven design offering good productivity and ease of service. Customers demanding the highest productivity and/or drilling in abrasive formations should consider either the QLX or Secoroc COP Gold hammers.These incorporate the latest technology and are the most reliable and productive hammers on the market.

Changing a Secoroc bit.

Blasthole Drilling in Open Pit Mining 53

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Open pit mining Mining operations typically have high equipment utilization, drilling up to 80% of the working day with DTH. The typical applications are normal 130-203 mm-diameter blast holes, 140-171 mm buffer holes, or 115-140 mm pre-split holes. Companies should consider either the QLX or Secoroc COP Gold hammers. These incorporate the latest technology, and are the most reliable and productive hammers on the market. For customers who are happy with rebuilds, Secoroc COP Gold is recommended, while for those who typically run hammers until they wear out, QLX will be the first choice.

Selecting the right hammer

ROC L8.

Dimensional stone quarrying demands consistent hole straightness, and such operations typically use smaller size holes of 90-105 mm in limestone, granite and marble. Here the QLX 35 hammer is the best choice. Mineral exploration Mineral exploration generally occurs in very remote locations, requiring robust hammers capable of running high pressures, in sometimes dirty environments. 54

For true reverse circulation drilling with face collection in mineral exploration and in-pit grade control, the Secoroc RC50 Reverse Circulation Hammer, incorporating the Quantum Leap cycle, performs particularly well. Geotechnical Environmental monitoring applications will appreciate the Secoroc Quantum Leap or COP hammers. Drilling of holes for foundation, anchoring or drainage also demands reliable, works horses like the QL range of hammers.

The optimum hole range of blast holes for DTH drilling is 90 mm to 254 mm. Smaller holes are generally drilled using top hammer, and larger holes generally use rotary machines. As a rule of thumb, the smallest hole diameter a DTH hammer can drill is its nominal size. A 4 inch hammer will drill a 4 inch (102 mm) hole. The limiting factor is the outside diameter of the hammer, because, as hole diameter reduces, airflow is restricted. Maximum hole size for production drilling is the nominal hammer size plus 1 inch, so for a 4 inch hammer the maximum hole size is 5 inch (127-130 mm). Choosing the right hammer is largely determined by hole size and type of rock formation. Ideally, the size of the hammer should match the required hole dimension as closely as possible, leaving just enough space for cuttings to evacuate the hole. Secoroc hammers are purpose-matched for all rock types and applications. Where high performance is the main criterion, Secoroc COP Gold and Secoroc QLX hammers are recommended. In deep hole drilling applications, the QLX hammer has proven superior performance and adaptability to different air requirements, thanks to the Air-Select System. Where proven technology is required, the Secoroc QL series of hammer are known for their reliability and longevity, and for a reliable workhorse. The Standard design for COP 54 and COP 64 Gold hammers can be used Blasthole Drilling in Open Pit Mining

Talking Technically

DM45 Blasthole Drill.

down to a depth of 330 ft (100 m) using a Standard bit size, making it useful for production drilling in quarries, shallow waterwell drilling, and underground blasthole drilling. QM (quarry mining) is similar to Standard, but with heavy duty chuck and wear sleeve, and a backhead fitted with tungsten carbide buttons for wear protection in harsh and abrasive conditions. These also protect the top sub from excessive wear when rotating out of the hole through broken rock Soft rock

Highest performance The Secoroc COP Gold and QLX hammers are designed for the most demanding drilling conditions and for those applications requiring premium performance. These hammers feature state-of-theart technology and deliver both maximum productivity and profit. Secoroc COP Gold • Superior longevity and reliability. • Easy to service and rebuild.

• Best suited for production drilling because of its excellent external wear resistance and longevity. • Internal components coated for wear and corrosion protection. Permits multiple rebuilds. • Three start chuck thread for easy bit changes. • Bit replacement possible without using drill rig break-out chains and wrenches. • Unique air cushion reduces wear and tear on drill string and rig.

Medium hard rock (220 Mpa/32000 psi)

Hard rock

Flat front HD SpeedBit Convex/Ballistic Concave Concave DGR Rocket bit ballistic Rocket bit spherical Bit designs and rock types.

Blasthole Drilling in Open Pit Mining 55

Talking Technically

Bit designs

Facts Convex/Ballistic front design Convex front with large cutting grooves and ballistic gauge and centre buttons. For soft to medium hard non-abrasive formations. The bit is designed for maximum penetration rate. Also, an alternative in hard abrasive formations, if high penetration rate is called for. SpeedBit Flat front design/ballistic centre buttons. Flat front with spherical gauge buttons and ballistic centre buttons. For high penetration in medium hard to hard abrasive formations.

Secoroc QLX • Provides the industry’s highest power output. • Best suited for deep hole applications. • Industry-leading simplicity and serviceability, resulting in very low operating costs. • Features modular components, snap-in cylinders, a reversible casing, backhead saver sleeves, and many options. • The hybrid valved/valveless design maximizes air compressor productivity.

Selecting the right bit Flat front design – HD Flat front with large spherical gauge buttons for hard and abrasive formations. Also, front flushing grooves for efficient cuttings removal.

Concave front design Concave front with spherical buttons Perfect choice for medium hard to hard, less abrasive, fractured formations. Minimizes effect of hole d­ eviation.

Concave front design – HD Concave front with spherical buttons, with larger gauge buttons. Ideal for medium hard to hard, abrasive and fractured formations.

Concave DGR front design Concave front with double rows of spherical gauge buttons. Only available for 8 in bits and larger. The reinforced gauge gives superior protection in medium hard to hard, abrasive and fractured formations. Rocket bit Super high penetration in soft to medium hard formations with low silica content. The Rocket bit also handles difficult formations with clay intrusions where other bit designs will not work.

The Secoroc range of DTH bits ensures that every driller can demand a solution for every application.

56

Atlas Copco Secoroc has a comprehensive range of DTH drill bits to match all conceivable applications. Each bit is made from quality alloy steel, and has been precision machined to produce a perfect body, heat treated to the required hardness, given surface compression for fatigue resistance, and fitted with precision buttons manufactured in-house. Five basic designs are available: CV Bit, FF Bit, SpeedBit, CC Bit, and Rocket Bit. These are designed for specific applications for all rock types, hardnesses and conditions. Bit life and rate of penetration are the most important criteria in selecting the right bit for a particular application. In most cases, the focus is on productivity, so the fast cuttings removal features of the SpeedBit and Convex/Ballistic designs are preferable, to ensure the buttons are cutting clean, with the minimum of re-crushing. In hard and abrasive formations, however, the flat front (FF) HD design offers best bit life, having strong gauge rows with large spherical buttons which are easy to regrind and maintain. The SpeedBit offers improved productivity with the same gauge as the FF HD, but with ballistic buttons in the front for faster penetration. An alternative is the Concave design with spherical buttons. The Rocket Bit can be dressed with ballistic buttons for use in soft to medium hard formations where fractured rock can be expected, or can be supplied with spherical buttons for hard and abrasive formations. Bits are manufactured to match all diameters of all Atlas Copco Secoroc hammers. Blasthole Drilling in Open Pit Mining

Talking Technically

Selecting the right tube Key features of a high quality DTH tube are durability, accuracy and manageability. Atlas Copco Secoroc tubes are made from cold drawn tubing, providing a superior surface finish and tolerance compared to conventional tubes made from hot rolled tubing. This drastically reduces the risk of scaling from the tubes entering the hammer, a major cause of premature hammer failure. The joints are friction welded to achieve maximum strength, and the threads of the end-pieces are heat treated for optimum durability and strength of the thread profile. This not only ensures long thread life, but also makes coupling and uncoupling quick and simple, reducing drilling time. Tube diameter should be close to the hammer diameter to provide optimum flushing, reducing the chances of getting stuck. In most applications, Atlas Copco Secoroc standard API threads will be the best choice. Atlas Copco Secoroc also offers a wide range of subs and crossover subs to meet an array of demands, all manufactured to the same standards as the tubes.

Secoroc COP 54 Gold - the production driller´s best friend.

COP Backhammer The COP Backhammer is a tool that can save and recover a drill string stuck in a hole. It can be easily fitted in a suitable tube joint between the drill support and the rotation head to provide an effective combination of backward hammering and vibration to loosen stuck drill strings.

Quality API grade N-80

Standard tubes

End pieces and adapters

min 550

min 550

Tensile strength

N/mm2 N/mm2

min 650

min 700

Elongation A5

min %

18

21

Core hardness

HB

190–230

210–250

Surface hardness

HRC

Lower yield limit

58–62

Service and support Atlas Copco Secoroc service, support and training follows every purchase, to ensure that customers extract maximum productivity from their drilling operations. Having a knowledgeable and available Secoroc drilling engineer on site or on-line makes the difference between going it alone and tapping the experience and know-how of a worldclass partner. For example, Secoroc knows that using higher productivity bits reduces the cost of each drilled hole, and the simplest way to cut costs is to drill holes faster. This has been

Drill tube OD (mm)

Wall (mm) RD 50

70 3.6 ■

23/8" 23/8" 27/8" 27/8" 31/2" API Reg API IF API Reg API IF API Reg ■

76

3.6 ■

76

5.6 ■

89

3.7 ■

89

5.7 ■

102

5.7 ■

114

4.3 ■

114

5.7 ■

114

7.9 ■



■ ■

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With on-site support, the choice of DTH equipment is even easier to make.

a focus of product development, and is at the core of Secoroc technology, ensuring that every generation of products drills faster and more efficiently. It takes a support team to apply this knowledge, so that customers can be 58

assured they run a profitable and efficient drilling operation in an increasingly competitive business climate. The bottom line is that the customer can count on Secoroc service and support, supplied by the largest, most

dedicated manufacturer of DTH drilling tools in the world.

Leif Larsson

Blasthole Drilling in Open Pit Mining

Talking Technically

Blasting in open cut metal mines Explosives Since blasting was introduced in mining as part of the production process, blasting technology and blast management have been interconnected. Explosives have been the primary method of breaking and loosening rock since the introduction of black powder. Over the years, however, blasting technology such as the physical properties of explosives and types of detonators has evolved. The same holds true for the process of blast management – from design principles for production blasts that are cost-effective and optimize mining operations, to safety and accident prevention during every step of the drilling and blasting process. Drilling and blasting results have a major impact on many processes in a mine. Therefore, it is important to find the right combination of drill pattern, explosives and blast design to contribute to the economic success of the total mining operation.

Principles When properly initiated, commercial explosives are rapidly converted into gases at high temperature and pressure. When detonated unconfined, a liter of explosive expands to around 1000 litres of gas in milliseconds. When confined by rock, expanding explosion gases result in extremely high stresses in the rock. The gas energy released during detonation acts equally in all directions but tends to escape through any path of least resistance. Therefore, blastholes should be charged and stemmed so that the gases are confined for sufficient time to provide optimum breakage, displacement and looseness of the blasted rock. The majority of explosives used in today’s surface metal mines are primersensitive explosives. Under normal conditions of use, a primer is required to initiate them reliably. All primer-sensitive explosives cotain the following essential components:

Bulk explosives are loaded using an Orica Mobile Manufacturing Unit (MMU ®).

• An oxidizer: a chemical which provides oxygen for the reaction. Ammonium nitrate is the most common oxidizer; • A fuel: which reacts with oxygen to produce heat. • A sensitizer: which provides voids that act as “hot spots” where the reaction starts during detonation. Sensitizers are generally air or gas in the form of very small bubbles, sometimes encapsulated in glass microballoons (GMBs). An explosive is classified as detonatorsensitive if it can be reliably initiated in an unconfined state by a #8 strength detonator (which has a base charge of 0.46 g of PETN). Detonator-sensitive explosives may or may not contain ingredients that are themselves explosives.

Properties of explosives The physical characteristics of the various types of explosives differ markedly. For example, ANFO type explosives are loose, free-flowing, granular compositions, whereas emulsion explosives have a consistency that varies from that of

syrup to firm putty. There are also various blends of emulsion and ANFO type explosives, notably so-called heavy ANFOs. Watergel (slurry) explosives are also used in some countries. The physical properties of the explosive can dictate the handling system used to charge the explosive into blastholes.

Water resistance

The water resistance of explosives varies considerably. Emulsions have excellent water resistance; heavy ANFOs have some water resistance while ANFO has negligible water resistance.

Density

The in-hole density of explosives has a significant effect on the energy per meter of charge length. Higher-density explosives generate more energy. Explosives are supplied in different densities to enable the shotfirer to control the total energy released in a blasthole to suit the particular blasting conditions and to achieve the desired result.

Sensitivity

Sensitivity is a measure of the ease with which an explosive can be initiated by

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responsible for conditioning the rock and initiating mechanisms that generate fractures. The “gas energy” or “heave energy” is delivered during the later expansion of the explosive products into the crack network of the rock. Once a fracture network is established the gas is able to expand into the network, both extending the fracture process and causing movement of the rock. As this happens, the gas pressure drops until it vents to the atmosphere.

Drilling at the Aitik Mine, northern Sweden.

heat, friction impact, or shock. The trend in commercial explosives is towards lower sensitivity to initiation without detracting from detonation efficiency.

Critical diameter

The critical diameter of an explosive is the diameter below which a stable detonation does not occur. To ensure reliable initiation under normal conditions of use, explosive suppliers recommend a minimum diameter for each of their products. To ensure reliable results under most conditions, the recommended minimum diameter is larger than the critical diameter.

Desensitization

Most explosives become less sensitive at higher densities. Desensitization can occur at excessive hole depths due to the static head of pressure. It is also possible for explosives to be dynamically desensitized by nearby earlier firing charges.

Velocity of detonation (VOD)

VOD is the speed with which the detonation propagates through a column of explosive. Two explosives having the same strength but different VOD may perform quite differently in a blast. As a general rule, the higher the VOD, the greater the shock energy and the lower the heave energy. However, it is important not to correlate shock energy directly with fragmentation energy. 60

The VOD of explosives used in surface metal mines vary between about 3000 m/s and 7500 m/s. The VOD of many explosives increases with charge diameter and confinement. Because of their high degree of refinement and efficiency, emulsion explosives can maintain very high VOD even with poor confinement and in small diameters.

Energy/strength

The energy of an explosive expresses the ability of the explosive to do work. An explosive with greater energy will be able to do more work on the surrounding rock. Energy produced by an explosive can be calculated using thermodynamic codes and measured using a variety of techniques.

Primer-sensitive explosives

Primer-sensitive explosives have relatively low sensitivity to shock, friction and impact, resulting in excellent safety and handling characteristics. The reliable detonation of primer-sensitive explosives requires initiation by a primer (e.g. Pentex™) that is in good contact with the charge. Ammonium nitrate is the major ingredient of most primer sensitive explosives.

Shock energy, gas energy and heave energy

Following detonation, high-pressure gases compress and crush the rock immediately surrounding the explosives. This results in an increase in the size of the blasthole and will vary according to the characteristics of the rock. The energy that is released by the explosive can be partitioned into two main types, the shock energy and the heave energy. The shock energy that is delivered to the rock is related to the extent and the rate of the borehole expansion to a socalled equilibrium state and includes the effects due to sub-optimal initiation. The energy delivered thus far is termed “shock energy,” which is primarily

Detonator-sensitive explosives

Detonator-sensitive explosives include Pentex™ boosters and Senatel™ packaged emulsions, which can be reliably initiated by a single #8 strength detonator or by a strand of 10 g/m detonating cord.

Initiating systems

Initiating systems are used to safely initiate charges of explosives at predetermined times by carrying a firing signal from one place to another, using chemical or electrical energy. Blasthole Drilling in Open Pit Mining

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Modern initiating explosives incorporate various explosive and inert components, which are partly or wholly consumed in the blast. Small quantities of signal tubing or wire often remain in the muckpile. Non-electric initiating explosives use pyrotechnic compositions or explosives to store and transmit energy by controlled shock waves, detonation or burning. Electric initiating systems require an exploder to generate an electrical charge, which is transmitted along wires. Blast timing is usually controlled by pyrotechnic (burning) delay elements located inside detonators. Non-electric initiating systems based on a signal tube are currently the most widely used for blasting in surface metal mines. Most mines now use nonelectric detonators inside blastholes, with remote initiation of blasts using a non-electric firing system. Electronic blasting systems are becoming more common, and differ from electric and non-electric delay systems in that the delay time is controlled by a programmable integrated circuit, resulting in very precise timing. The accuracy and programmability of electronic detonators allows for blast timing to be tailored to the geometry, geology and unique requirements of any blasting operation to more effectively use explosives energy.

Examples of initiating systems produced by Orica.

Bulk explosives

Specialized equipment and tools are required to safely and effectively mix and charge explosives in surface metal mines. Most of the equipment and tools used in blasting operations are subject to statutory regulations. A Mobile Manufacturing Unit (MMU®) is designed to produce and deliver specif ied bulk explosives from a manufacturing unit based on a conventional truck chassis. Orica MMU®s are able to carry large quantities of non-explosive raw materials to the mine site, avoiding the need to carry explosives on public or mine roads. The bulk explosives are manufactured at the blasthole collar and accurately delivered into blastholes at high discharge rates. MMU®s are produced in a variety of configurations to meet specific needs. The complexity of

Electronic Blasting Systems can enable a mine to more efficiently achieve its productivity, safety, and environmental performance objectives..

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designs developed, and possibly to indicate alternative superior designs. Initial blast designs must then be progressively improved to optimize mining operations and costs. Optimum designs help to produce the required fragmentation, muckpile looseness, muckpile profile, toe conditions and grade control. In some cases, blast designs must also minimize flyrock and control ground vibrations and air overpressures.

Design variables

The Mobile Manufacturing Unit on site (MMU  ®).

the onboard manufacturing facility depends on the type and number of explosives required. The truck on which this is mounted is selected to suit the material to be carried and the terrain on which it will operate.

Explosives selection, priming and charging Priming and charging of blastholes is one of the most important parts of a successful blast. Blastholes must be accurately primed and charged to the design specified by the blast designer. The objective when selecting a combination of explosives is reliable performance, which will ensure the lowest overall operating costs without sacrificing safety. When selecting explosives, the first considerations are the site geology and the end objectives of blasting. Once assessed, there are other important considerations such as: • Ground water conditions; • The properties of the rock being blasted, i.e. strength, structure, etc.; • The diameter and depth of blastholes; • Drilling costs and drilling capacity; • The relative explosives cost per unit of effective energy; • The fragmentation and heave characteristics of the explosives; • Shelf life; • Desired results. ANFO has often been selected when blasting dry blastholes. Wet blastholes 62

ideally should be charged with a waterresistant explosive, either an emulsion or a watergel. The explosive will displace the water up the hole, which may flow into adjacent dry blastholes. While ANFO is considered somewhat of a reference point, there has more recently been an increased emphasis on both lower and higher energy bulk explosives to meet the evolving demands of the mining industry. Other options that may be considered are: • Dewater the holes using in-hole pumps, compressed air or other means, and then treat them as blastholes containing nuisance water by charging with water-resistant bulk or packaged explosives to above the original water level, then continuing with ANFO. • Charge the wet blastholes with packaged explosives until above the water level. Then charge with ANFO.

Blast design When starting to work a new mine or a new area of an existing mine, it is necessary to develop one or more initial designs for production blasts. In this situation, some “rules of thumb,” derived over many years of relevant practical experience, should be used for developing these designs. If a detailed assessment of rock mass properties has been carried out, computer modeling can be used to assess the suitability of the

Bench height normally lies in the range of 5-18 meters The selected bench height is influenced by: • Statutory regulations (excessively high benches are unsafe and, therefore, not permitted); • Rock mass properties; • The type and size of digging equipment; • Grade - control requirements; • The need to maximize the overall cost efficiency of drilling and blasting. Increasing bench height decreases total drilling consumption of primers and initiators, the labor required for firing, and the number of mining cycles. Optimum blasthole diameter increases with bench height. In general, an increase in blasthole diameter decreases the total cost of drilling. Drilling accuracy becomes more critical in higher benches and drill deviation can produce costly consequences.

Blasthole diameter

Optimum blasthole diameter is greater for higher benches and for larger digging, hauling and crushing equipment. Large diameter blastholes are less suitable in strong, massive rock; when minimal broken rock movement is required; or where it is very important to control blast vibrations. At large surface mines, the total cost of mining is usually minimized by drilling large diameter blastholes. Larger diameter blastholes reduce costs for drilling, primers and initiators and labor. They usually need higher powder factors than small diameter blastholes to give the same fragmentation, especially in strong rocks. Smaller blastholes give better distribution of energy in the rock mass. Blasthole Drilling in Open Pit Mining

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Free faces

Effective free face

Forward displacement of blasted rock occurs if a blast shoots to a free face (Figure 1). Some movement of the rock mass is necessary to allow for crack propagation. Increased movement assists crack propagation and can improve fragmentation. This may not be the main objective in some operations (e.g. blasting in ore) so free faces may be limited (choked) to restrict ore dilution.

Blasthole angle

Vertical blastholes are usually used in surface metal mines because: • Angled blastholes are more difficult to set up and drill; • Some drills do not have an angled drilling capability; and • Drilling accuracy is greater with vertical blastholes. In free-face blasting, vertical frontrow blastholes often leave variable and excessive burdens between the top and bottom of the charge (Figure 2). This variation is greater in high- or shallowdipping faces and can cause hard, immovable toe. Front row blastholes collared near the crest to control the toe burden can cause explosion gases to blow out prematurely in the face. (See Figure 3 and 4) This blow out has the potential to create noise, airblast and flyrock and reduces blasthole pressure near the bench floor level, which may prevent adequate breakage and movement of the toe. This may necessitate the use of some angled blastholes in front rows. (Figure 5)

Subdrilling and drilled length of blasthole

Efficient excavation needs toe conditions that suit the digging equipment. Toe conditions are affected strongly by the amount of effective subdrilling. Subgrade or subdrilling is the length of the explosive charge, which lies beneath the designed bench floor level. Unavoidable fallback of drill cuttings and small rock fragments reduces the effective subdrilling to less than that originally drilled. It is good practice to drill a certain extra distance (which is longer for higher benches and weaker rocks) to allow for unavoidable fallback.

Fig 1. Effective free face.

Caution! Excessive Burden

Airblast Flyrock

Required Burden Fig 2. Variable burdens, vertical holes.

Fig 3. Excessive blasthole angles cause problems.

Airblast Flyrock

Caution! Correct Burden

Fig 4. Problems with variable burdens.

Fig 5. Angled holes increases rock breakage.

Priming

Bottom priming has several advantages over top priming. They include: • Improved fragmentation, displacement and muckpile looseness; • Reduced toe problems, better floors, and cleaner faces; • Reduced noise, airblast, flyrock and surface overbreak; and • Fewer cut-offs and misfires.

The overriding concern in priming is to locate the primer in the explosives column and ensure operational safety and efficiency. The primer is generally placed at or near grade level. Some operators place the primer at a known distance above or below bench floor level to ensure that, should a misfire occur, the excavator operator does not dig directly into a primer. This may be a valid reason for not placing the primer at bench floor level.

Charge distribution

Distribution of the explosive charges in the rock mass is an important

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consideration when determining blast geometry. Crater blasting to a horizontal rock surface has a less efficient charge distribution but is preferred in shallow ore deposits where quality control dictates low benches, despite a higher explosives consumption.

Blasthole pattern

(a) (a) Paddock Paddock blast blast –– staggered staggered

(b) (b) Paddock Paddock blast blast –– square square

Blasthole patterns depend on blasthole diameter, rock properties, explosive properties, bench height, and the results needed. Operating experience and blast modeling results have shown that, in massive rocks, better fragmentation and productivity are obtained with staggered patterns than with either square or rectangular patterns. Equilateral triangular patterns provide optimum distribution of explosion energy in the rock. While staggered patterns give the best theoretical performance, the initiation sequence can alter the geometry and results of blasts on square or rectangular patterns.

Spacing-to-burden ratio

(c) (c) Paddock Paddock blast blast –– rectangular rectangular

Burden and spacing are related to blasthole diameter, depth, rock type and charge length. Blasthole spacings considerably smaller than the burden tend to cause premature splitting between blastholes and early loosening of the stemming. This can cause premature release of explosion gases to the atmosphere and considerable overbreak. Loss of heave energy reduces breakage and produces large rock slabs in the muckpile. On the other hand, a spacing-to-burden ratio that is too large can cause the face midway between back-row blastholes to remain intact, especially near bench floor level. This results in tight digging and possibly unbroken toe.

Front-row blastholes

d) Square – Fired on Echelon Fig 6. Blasthole patterns.

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Special attention should be paid to the position of front-row blastholes. If the burden on front-row charges is excessive, it will not be broken by the time second-row charges detonate. Restriction of motion at the beginning of the blast can prevent optimum blasting results throughout the blast. Where burden is too small, explosion gases burst rapidly through the face, causing noise, airblast and flyrock. Blasthole Drilling in Open Pit Mining

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Changing burden and spacing

Changes in burden generally affect fragmentation, muckpile looseness and toe much more rapidly than changes in spacing. If enlarging a blast pattern for improved economy, it is more common to increase the blasthole spacing in steps before altering the burden.

Stemming

Stemming enhances fragmentation and rock displacement by reducing premature venting of high-pressure explosion gases to the atmosphere. (Figure 7) Dry granular materials are best for stemming because they have inertial resistance and high frictional resistance to ejection. Materials that behave plastically or that tend to flow are not suitable for stemming, e.g. water, mud, wet clay. Stemming length can be reduced significantly if effective stemming is used, resulting in better explosive distribution and improved overall fragmentation. Optimum stemming length depends mainly on blasthole diameter, stemming material, and surrounding rock properties. Inadequate stemming increases collar rock breakage, but decreases overall fragmentation and displacement because explosion gases vent to the atmosphere more easily and rapidly. It also creates more flyrock, surface overbreak, noise and airblast. Long stemming lengths ensure good confinement of explosion gases, but fragmentation of collar rock becomes coarser.

Size and shape of blasts

Most oversize rocks come from the back, sides and top of blasts. Boulders are created by open fractures in the free face, irregular burdens and by backbreak around the perimeter. Damage from previous blasting around the perimeter opens fractures which define rocks isolated from the rock mass. These rocks are not fragmented by explosion-generated strains and cracks, but are merely pushed forward into the muckpile. In addition, large rocks that have been torn loose or dislodged can slide from the new faces into the muckpile. Increasing the blast size reduces the proportion of large rocks from the blast perimeter, and therefore improves overall fragmentation.

(a) Excessive Airblast & Flyrock

(b) Good breakage & displacement (c) Poor fragmentation

Fig 7. Effect of correct and incorrect stemming.

Allocation of delays

The sequence in which blastholes are initiated and the time interval between successive detonations has a major influence on overall blast performance. The performance of production blasts can only be optimized when charges detonate in a controlled sequence at suitable discrete, but closely spaced, time intervals. Optimum delay allocation for a blast depends on many factors, which include: • Rock mass properties (strength, Young’s modulus, density, porosity, structure, etc.); • Blast geometry (burden, spacing, bench height, free faces, etc.); • Diameter, inclination and length of blasthole; • Explosive characteristics, degree of coupling, decking, etc.; • Initiating system (surface or in-hole delays, type of downline, non-electric or electronic, etc); • Type and location of primer; • Environmental constraints (air and ground vibration levels and frequency); and • The desired result (fragmentation, muckpile displacement and profile etc.). It is not possible to determine optimum delay allocations from first principles, but blast monitoring, analysis and interpretation have led to a greater understanding of the mechanisms and significance of blasthole interaction.

Delay along rows

The delay time between adjacent blastholes in a row is sometimes called the intra-row delay. Firing a single row of blastholes with the optimum delay between holes produces: • Optimized fragmentation for that particular blast geometry; • Forward displacement, which is less than that for an instantaneous singlerow blast; and • Reduced overbreak.

Delay between rows

The delay time between the initiations of rows of blastholes is sometimes termed the inter-row delay. The delay between rows can be as important as the delay along rows in controlling overall blast performance. Multi-row blasts are fired using a time delay between the detonations of successive rows of blastholes. The burden on each blasthole needs time to move after the detonation to create an effective free face. Dependent blastholes then fire towards this new free face developed during the blast. (Figure 8)

Hole-by-hole initiation

In many situations the simplest method of blast initiation hook-up is to fire blastholes row by row or simultaneously along echelons. This will rarely produce optimum blast performance, especially in terms of fragmentation or ground vibrations. The end result can be improved by introducing hole-by-hole

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3

2

between the back row and the pit limit is too small, there will be too much overbreak into the final face. If the standoff distance is too large, digging back to the design final face will be difficult, expensive and may need a bulldozer. (Figure 9) • Blasthole depth– If blastholes are drilled into the berm below then the succeeding wall will be damaged. Sufficient standoff distances need to be maintained to designed crests.

1

(a) Good "Relief"

Smoothwall blasting techniques

2

1

3

(b) Insufficient "Relief" Fig 8. Burden relief.

firing, where every blasthole is initiated in sequence at a unique time. Where appropriate delays are selected, hole-by-hole initiation exploits the positive benefits of blasthole interaction while avoiding most of the negative effects. This leads to improved fragmentation and muckpile looseness, reduced overbreak, lower ground vibrations, and better control over the final muckpile position and profile.

Final wall blasting

At most open pit mines, the final slope of the pit affects profitability appreciably. Steep stable pit walls can be formed by smoothwall blasting techniques, which include cushion blasting, presplitting and postsplitting. But with each of these techniques, the combined cost of drilling and blasting is relatively high. In some cases, stable pit walls can be formed without smoothwall blasting. 66

Careful blast design is the key to producing clean, safe pit walls at minimum cost. The blast design needs to consider the rock conditions in the area, the likely amount of backbreak from this blast, and the design location of the final pit limit. Key factors to consider in final wall blasting are: • Geology – Rock properties have the greatest influence on the effect of blasting on pit walls. Heavily jointed rock often produces overbreak along joint planes. • Blasthole location – The location of the back row of blastholes is critical to the location of the final pit limit. The back row of blastholes needs to be drilled in front of the final pit limit to allow for backbreak behind the blastholes. The correct location depends mainly on previous experience in the pit and trial and error, particularly if the amount of backbreak is variable. If the standoff distance

Cushion blasting, postsplitting and presplitting are the three common blasting techniques used to produce stable final walls. Postsplit and presplit blasts are often used alone to produce stable walls. Cushion blasting is frequently overlooked when designing final-wall blasts, but can be the most versatile and useful method of the three techniques. The back-row blastholes in a cushion blast contain lighter charges than the production blastholes, and are drilled on a correspondingly smaller pattern. Cushion blastholes are usually the same diameter as the production blastholes in front of them. Charge weight is commonly reduced by about 45 percent, and both burden and spacing by about 25 percent. The energy factor is therefore essentially the same throughout the final wall blast. A postsplit blast consists of a row of parallel, closely spaced blastholes drilled along the final face. These blastholes are charged with a light, welldistributed charge, and fired after the production blastholes in front have detonated. Postsplit blastholes split the rock web between the blastholes to produce a sound smooth face with minimal overbreak. Presplitting requires a row of closely spaced blastholes drilled along the design excavation limit, charged very lightly, and detonated simultaneously before the blastholes in front of them.

Special blasting techniques While the main emphasis in surface metal mines is on production blasting, Blasthole Drilling in Open Pit Mining

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there are times when special blasting techniques are required. These include: • Opening up new benches using either drop cut or ramp blasting • Mining of weathered and fresh rock • Dilution control • Choke blasting • Blasting ore and waste together • Steeply dipping multi vein orebodies • Shallow dipping narrow vein orebodies • Flat or bedded orebodies • Selective ore blasting • Separate ore and waste blasting • Deck charging • Secondary blasting and popping • Plaster blasting • Floor and toe blasting

Could be Presplit

Production Blastholes

Final Limit

Maybe Smaller Diameter

Reduced Energy per m

Safety and accident prevention

Safe and cost-efficient blasting requires all mine operators and supervisors to understand and follow correct procedures for handling and using explosives. Most mines now have on-site induction training to develop skills for specific jobs, including blasting. Many mines have written work procedures, which specify the method, tools and equipment to be used for each job. These procedures, combined with local mine rules and statutory regulations, are designed to maintain the health and safety of all people working in the mining environment. Blasting requires the use of special tools and equipment, which are usually subject to statutory regulations. All tools and equipment used for charging and firing explosives should be properly maintained, regularly checked and correctly used. There should be no improvisation or substitution, as this can cause injuries and accidents. There are many hazards when working in and about a mine. The additional hazards associated when using explosives that need to be mitigated are: • Electrical hazards that can affect the use of electric detonators. The sources of electrical current are static, stray currents from machinery, lightning and radio frequency energy. • Heavy impact on initiating explosives • Vehicles driving over explosives • Hot and reactive ground

No Subgrade Final Limit

Fig 9. Placement of blastholes along final pit limits.

• Misfires • Fume • Walking on rough ground and around blast holes • Vehicle and pedestrian congestion on the bench

Charging blastholes safely

Before charging commences, the blasting area should be barricaded and marked with cautionary signs and lights. All unnecessary tools, equipment and people not involved with blasting should be removed from the area. Smoking must not be permitted near explosives or charging operations. The quantity of explosives delivered to the job should not far exceed immediate requirements, and any unused explosives must be returned to the magazine when charging has been completed. Explosives and detonators must be kept apart in separate containers until charging commences. These containers should be located in a safe place, clear of equipment, and marked by appropriate signs or lighting. Electric detonators must be kept clear of all sources of electricity and all

potential conductors of stray currents. Electric detonators should be kept coiled, with the lead wires shorted together, until they are used. All blastholes should be cleared of obstructions and checked for length before charging. Drilling sludge and loose rocks should be washed or blown out before charging.

Economics and benefits Cost effectiveness of drilling and blasting can be defined in many ways, but the “bottom line” is that these operations must contribute to the best overall economic result for the total mining operation. Drilling and blasting influences many different processes in a mine, with the benefits of a cost-effective blast being felt anywhere from digging to maintenance, hauling, crushing and milling, ore recovery to labor utilization and secondary breakage. Therefore, decisions on drilling and blasting need to be made in the overall context, and should not generally be based on short-term economic factors. The development and introduction of bulk explosives and efficient delivery

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Cost per Tonne

Total Costs

Unit Costs ($)

Zone of Minimum Total Costs

Load & Haul Crushing

A Drill & Blast

B

Secondary

C

Fragmentation Fig 10. Costs versus fragmentation.

systems has provided a quantum step forward in blasting efficiency and has allowed cost reduction through economies of scale. The factors contributing to economic production in mines include:

Productivity

• Overburden/waste removal • Primary raw feed/mine production/ sales tonnage • Mobile equipment capacity/type and availability • Fixed plant capacity/type • Ore grade control factors • Maximizing reserves through structural stability • Minimizing stripping ratio: waste/ ore

Mine conditions

• Type and extent of overburden/ waste • Rock type and geology • Height and inclination of operating benches • Ground water conditions • Environmental constraints

Labor force competence • Training • Motivation and numbers

Operating costs vs fragmentation Drilling and blasting results have a major impact on each part of a mine's 68

operations. The optimization criteria for mine production operations can be expressed as finding the right combination of activity costs, and managing them in order to minimize the overall production costs (Note: this does not mean that reducing any particular parameter in isolation will necessarily result in a lowering of overall costs). Figure 10 schematically represents the activity costs as a function of maximum fragmentation size. The relationship between these activity costs varies from mine to mine. The curve is divided into three zones – A, B and C. Zone B is where the total costs are minimized within a controllable and acceptable range. In zones A and C the unit costs of one or more activities make the overall production cost excessive. In this case, the cost effectiveness of blasting does not necessarily increase with a decrease in blasting costs, and changes can often be counterproductive. The best time to break rock is undoubtedly during the primary blast– the aim being to achieve desired and predictable fragmentation, muckpile looseness, and a suitable muckpile profile for ease of digging. During the evaluation, other key issues may be: • To modify fragmentation to suit excavator or crusher specifications; • To make blasting more environmentally acceptable; • To improve labor utilization allocated to blasting;

The PV-351 can drill blastholes up to 16 inches in diameter.

• To reduce blasting costs, particularly in wet areas; • To protect pitwalls or control overbreak damage; and • To maximize recovery of product ore. The process of optimizing blasting must be done in a controlled manner so that the inf luence of changes on blast performance can be measured and evaluated. It is most important that changes are made one at a time, and that a thorough analysis of the total cost and the blast performance are made to enable any benefits to be identified and quantified.

Acknowledgements Article provided by Orica, the world's leading provider of commercial explosives, blasting systems and blast based services. Read more at: www.oricaminingservices.com Blasthole Drilling in Open Pit Mining

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Fuel saving clutch Automatic clutch system With rising diesel and electricity costs, reducing fuel consumption is vital to stay competitive in today’s market. A new innovative solution to reduce the fuel consumption in drilling applications is the patent pending automatic hydraulic clutch. It disengages the compressor from the diesel engine during non-drilling operations.

Turning the compressor off Atlas Copco is once again taking the industry lead by introducing and implementing the patent-pending automatic clutch system on selected surface drilling machines. Although this is new to the mining market, it is a time proven technology that has been used in other industries. Through an integrated clutch-control unit that activates the clutch, our engineers have developed this option to help mines save on the fuel costs and maintenance, and to contribute in helping the environment by drastically reducing the amount of fuel consumed by our machines. Typically, if you were to study a drill in a surface mine, you would find it performing one of the following tasks: drilling, propelling/tramming, leveling and rod handling. Today, both the engine and compressor run at all times for all five functions, although the compressor is only required for one of these tasks: to get the cuttings out of the hole during the drilling cycle. Wouldn’t it be advantageous, though, to only use the compressor during drilling and not for the other four phases? For example, turning the air compressor on-and-off when deemed necessary and saving horsepower drawn on the engine would be greatly beneficial. Even with the air switched off the compressor still uses approximately 30% of the rated horsepower even in standby mode. This action alone could ultimately save

The automatic clutch system was first introduced for the Pit Viper 235 series and is now also available for the PV-271, PV-275 and PV-311.

a mine thousands of dollars in fuel and maintenance costs – not to mention the vast impact that less fuel usage would have on the environment.

No change to rig operation With the addition of the clutch system, it is important to note that the operation of the machine will remain the exact same; the clutch integration is minimal (which also means the clutch can easily be retrofitted to a machine already in the field) and will not require any additional inputs from the operator (See Figure 1). Once the operator is ready to drill another hole, they set up the machine as usual and then turn the air “ON”. At this moment a signal is sent to the clutch control unit and the engine

speed automatically drops to around 900 rpm and the clutch begins feathering the engagement. Once the speed of the compressor matches the speed of the engine, the engine automatically ramps back up to full speed, the air is now “ON” and the compressor has already started to generate air. All of this happens within three seconds, so there is no visible delay. Once the hole is drilled, the operator then turns “OFF” the air, disengaging the compressor, and moves on to the next hole. Let’s look at a scenario that utilizes the exact same machine drilling both single-pass and multi-pass, with and without a clutch. If two machines are compared, one with the clutch system and one without

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le a

nin g

Posi tio ni

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• The clutch omits the parasitic load of the compressor on the engine during start-up, specifically in cold weather environments. This ultimately increa ses engine and compressor life over the life of the machine. • On previous configurations, the com pressor did not have a dedicated hour

Leveling ng

ec

ol

g

n

Combined with Atlas Copco’s large capacity fuel and water tanks, the clutch system can greatly increase production time while reducing the amount of time that fuel and water trucks spend making trips down to the machine at the bottom of the pit. For example, a

Three benefits of the clutch option

Figure 1: Clutch system, the patent pending automatic clutch system supplied as an option for selected rotary blasthole drill rigs. Below: A rig equipped with this system only uses compressed air for drilling and hole cleaning (yellow arrows).

mi

Added advantages

mine can maximize the fuel capacity on a PV-275 up to 2,365 liters (625 gallons), and still have a 3,100 liter (822 gallon) water tank. The combination of the large fuel and water tanks would allow the machine to run for over 24 hours of operation without the fuel truck needing to make a visit, as well as provide the machine with over 24 hours of water. As an ISO 14001 certified company, Atlas Copco continually strives to ensure that the highest environmental standards are adhered to during the design, assembly, and utilization of our machines. This additional and welcomed option is just one item in a large portfolio of options that we offer on our machines, all catered toward designing and manufacturing enviro mentally conscious equipment. The clutch system not only contributes to reducing a mine’s operating budget, but more importantly we are able to support the mine through a wide range of safety and environmental options. Our ability to do this ultimately helps our customers to pursue their goal of responsible mining, which benefits not only the environment but their personnel as well.

m Tr a

working in the exact same rock formation, it is easy to visualize the immediate fuel savings from one single-drilled hole. Extending out the fuel savings of one hole over a mine’s yearly production can greatly assist in increasing the bottom line. As we can see from the chart (Figure 2), the fuel savings tend to increase during multi-pass drilling since the machine spends more time performing non-drilling functions when compared to a single-pass machine. Furthermore, the fuel savings are also higher in soft rock formations when compared to a hard rock formation. The reason for this lies in the fact that in order to drill hard rock, the machine typically spends more time drilling the rock compared to handling the drill pipe, ultimately consuming more horsepower and fuel than a machine used purely for rotary drilling. Regardless of whether a mine is multipass drilling or single-pass drilling in a soft or hard rock formation, the reality is that there is potential for sizeable cost savings. In fact, with some preliminary studies of this option, we have seen some increasingly high fuel savings that could make a significant difference in any mines operating budget.

Pip e

h a n d li n

g

H

Working cycle.

meter and therefore the service inter val and rebuild time was dependant on when the engine had to be ser viced or rebuilt. With the clutch, the compressor has its own hour meter and its own service interval based only on hours of actual use. • The advantage of getting the job done with less fuel is an added bene fit in itself, not just for the mine but for the environment as well.

Maureen Bohac

WITHOUT Clutch WITH Clutch

Bench Height 11 35

14 75

35 115

47 155

53 175

m ft

Figure 2: Fuel Consumption based on Depth Drilled . An indication of fuel savings when drilling at different depths in soft formations. Savings with the clutch increase with the depth of the hole and number of pipe changes and will also be greater when drilling in soft rock where the rate of penetration is high. Actual savings must be estimated for each drill rig and application.

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Blasthole Drilling in Open Pit Mining

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The mid-range Pit Viper 235 The star of MINExpo 2008 The new ultra class haul trucks in the Central Hall arguably may have achieved the greatest visual impact at MINExpo 2008, but surface mine drillers attending the record-breaking Las Vegas show in 2008 hailed their own new star in the North Hall – the Atlas Copco Drilling Solutions Pit Viper 235 at the Atlas Copco display. This PV-230 class machine thus followed in the tracks of the first Pit Viper model, the PV-351, which was launched at MINExpo 2000, and the PV-270 series models introduced at MINExpo 2004.

Efficiency and productivity The PV-235 has a weight on bit of up to 65,000 pounds (29,500 kg) and is designed for rotary or downhole (DTH) drilling of 6-inch to 9 ⅞-inch (152 – 251 mm) diameter holes. Competitive performance and excellent long-term reliability have been key marketing points for the Atlas Copco Drilling Solutions range of drilling rigs for a long time. The PV-235 is specified and fabricated to maintain this reputation, with particular attention having been paid to the reduction of horsepower demand and non-drilling time. The cab and control technology have been significantly upgraded and the diesel engine options are Tier II and Tier III units. Atlas Copco Drilling Solutions has again placed great emphasis on flexibility in application, and the PV-235 is available with two towers to drill 35 ft (10.7 m) or 40 ft (12.2 m) clean 230 mm holes. The new machine can be configured in a surprising number of ways to offer an optimal match to a mine’s particular operating method and environment. Like the PV-351 and the PV-270 models, the PV-235 will be available with either a choice of diesel engines or an electric motor. And it retains the

Pit Viper 235 is capable of dilling a single pass 40 ft clean hole.

hydraulic systems, including the rotary head, that have consistently been preferred by the Atlas Copco design and engineering team for many years.

Less mass, more options Starting at ground level, the PV-235 has a newly designed platform. It is built with two-speed hydraulic excavator style Caterpillar 330 undercarriages – the 330L for units with the 35 ft tower, and 330EL when the

40 ft tower is fitted. The dimensions for the PV-235 version with tower up is 34 feet 2 inches long and 14 feet 6 inches wide (10.4 x 4.4 m). The high-speed tram operates with the tower lowered. The plate steel frame is new to blasthole drill construction and was designed using finite element analysis. The material thickness is one third that of an equivalent welded plate construction and has a better fatigue life. The frame accommodates the 450, 600, and 1050 gallon fuel and water tanks, which are

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The enclosure option will reduce noise and provide cold weather protection; full-length doors offer easy service access.

The hydraulic automatic cable tensioning cylinder is a time saver for maintenance .

For angle drilling the PV-235 uses a pivot at the base of the tower with adjustments from vertical to 30 degrees in 5-degree increments, while keeping the deck level.

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isolation mounted. An additional 400gallon water deck tank can be fitted if no dust collector is used. Another 200 gallon belly tank is now offered with the non-drill end deck extension. For safer, easier and quicker trouble shooting and maintenance, the Grip Strut open mesh deck provides excellent access to the superstructure elements, including ground level battery and starter isolators, deck level access for the service points on most systems, and quick fills at waist level. The deck hose and cable trays manage the routing and clean up the decking. An optional bolt-on drum deck on the drill end adds extra space for lube and other fluids storage tanks, and cleans up the deck area to allow 300° of access and improved serviceability. Other optional fittings include a central lubrication system, fire suppression equipment, a jump start receptacle and a spring assisted emergency ladder. For mounting on this platform, Atlas Copco Drilling Solutions has decided to offer customers a wider choice of power system options than on previous models. The structure is similar to that designed for the Pit Viper 351, with an independent sub-structure and threepoint isolated mounting. But there is a wider choice of Cummins or Caterpillar engines, covering the range 600 – 800 hp at 1,800 rpm with the Cummins QSX 15 to QSK 19 or Cat C18 to C27 engines, all meeting Tier II, III or IV regulations. There is also a wider choice of air compressors, as either single-stage asymmetrical oil flooded Atlas Copco or Ingersoll-Rand rotary screw units are available for low pressure (1,600 – 1,900 CFM, 100 psi) rotary drilling, and the two-stage equivalents for high pressure (1,250 or 1,450 CFM @ 350 psi or 1,300 CFM @ 435 psi) downhole drilling. An Electronic Air Regulation System (EARS) allows low load starting. An Atlas Copco patent pending automatic hydraulic clutch between the engine and the air end has been introduced during 2010 as a new option for the Pit Viper 235 series. The benefit of this clutch is that it will disengage the air compressor from the engine when the air end is switched off. In a traditional power package, the compressor consumes approximately 30% of its Blasthole Drilling in Open Pit Mining

Talking Technically

rated power at standby. Installation of this clutch eliminates fuel being used for this standby power consumption and allows for a low idle speed. While changing rods, levelling, or moving between the holes, the air compressor is disengaged allowing for horsepower savings during those cycles as well as increasing the service interval and life on the air compressor. The clutch removes parasitic engine loads at start up as the compressor is not engaged, therefore decreasing engine load and increasing engine compressor life. The hydraulic system has been further refined with load sensing pumps and other features to reduce horsepower demand. The heavy duty Funk gearbox is driven by a drive shaft from the front of the engine. There is one piston pump for rotation; one load sensing piston pump for the feed, set-up and auxiliary functions; and one pressure-compensated piston pump for the fan circuit. The propel function uses the feed and rotation pumps and there is an in-cab switch to select the diverter valves. The valve rack is centrally located for easy service access, at the same time simplifying hose runs and control wiring. The pressurized hydraulic fluid tank has a capacity of over 100 gallons and the filters are serviced at waist level. To allow operation at ambient temperatures up to 125° F (52° C) the cooling system features oversized radiators. Variable speed control helps to reduce fuel consumption and noise and improves cold weather performance. The low fan speed also lowers noise emissions. Available as an option is a very smart enclosure that further reduces noise, provides cold weather protection and has full length doors for service access.

The RCS provides various levels of automation.

and the updated four-rod carousel, the 40 ft tower can be used to multi-pass drill to a maximum depth of 200 feet (61 m). The PV-235 is fitted with a standard spur gear head design that is also used on the DM45 and DML. Alternatively there is the option to chose a two-speed

head delivering either 4,900 lbf-ft (6.6 kNm) at 110-190 rpm, or 8,200 lbf-ft (11.1 kNm) at 0-110 rpm. The options direct drive rotary head tends to require less maintenance than the standard spur gear head. Both of these rotary heads are fitted with adjustable wear guides that follow the length of the tower. The

Clutch

Output-side coupling

Bolts

Towers The open front structure of the two towers available is similar to that used on the other Pit Viper models – fabricated from rectangular steel tubing by certified welders and having four main vertical members. The 40-foot (12.2 m) and 35-foot (10.7 m) hole depths mentioned previously are the distance from ground level to the bottom of the hole, while the top of the bit basket is 5 feet above ground level. Using a starter rod

Input-side torsional coupling

The optional fuel saving clutch will disengage the compressor when not drilling.

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The FOPS designed cab offers excellent visibility and comfort.

single cylinder cable feed designed for the PV-235’s 40 ft tower provides a hydraulic pulldown force of 60,000 pounds and a further improvement in non-drilling speeds. The sheave diameter: cable diameter (D/d) ratio is 22:1 and reverse bending of the cables, which can create excess fatigue and shorten cable life, is eliminated. The pulldown rate is 140 ft/min with the 40 ft tower and 193 ft/min for the 35 ft tower. Retract is 202 ft/min with the longest tower and 195 ft/min for the other. Auto-tensioning of the cable, necessary to counter the loss of tension caused by cable stretch is by means of a single cylinder with exclusive balancing yoke. For angle drilling the PV-235 uses a pivot at the base of the rig tower, proven on the earlier Pit Vipers, with adjustment from vertical to 30° in 5° increments. But the rear telescopic support legs provided on the larger rigs are unnecessary. This single pivot design reduces non-drilling time significantly, with tower raising and lowering improved. The rig has a new twocylinder impact slide wrench for drill string breakout that has replaced the single-cylinder deck fork used on previous models. The new patented Atlas Copco twin cylinder break out-wrench is standard on the PV-235. Breaking the pipe joint is done below the table and 74

allows the deck fork to be used while clamping the upper rod and allowing for adjustment from 4 ½" - 8" (115-203 mm) OD drill pipe allowing for wear. The rear jacks are incorporated into the new tower rest, as are the exhaust mounts, air cleaners and lights. The arch-shaped tower rest adds torsional stiffness to the frame and riser arms secure the tower when it has been lowered, reducing wear during tramming. The optional non-drill end deck extension is provided with an integrated tower access, a fall restraint system and an extended tower infill for accessing the tower for service and maintenance while it is in horizontal position.

Even better cab Together with the power system enclosure, if fitted, the most distinctive feature of the latest Pit Viper is the cab. The cantilevered pod-type FOPS design is a further advance on the progress achieved with the PV-270 series machines in terms of both capabilities and appearance. Visibility is enhanced not only by the shape of the cab and large glass area, but also by tinted windows, improved wiper/washers and six Nordic integral lights (which also consume less power than conventional ones). The integrated air conditioning

system, with a hydraulically powered compressor, evaporator and condenser, is mounted under the cab rather than on the side. The Atlas Copco engineers worked with the cab supplier to achieve further noise reduction and have tested at 70 dBa. For easier “housekeeping” there are fitted floor mats and a sweepout door at the non-drill end. Optional offers are a safety camera system and a radio/CD player for the cab, as well as a Roll Over Protection Structure (ROPS). The standard controls are the proven Atlas Copco RCS computerized network rig control system, which provides various levels of automation, in common with the rigs manufactured by the company’s surface and underground teams in Sweden. For the PV-235 these options include remote tramming, auto leveling and GPS navigation, all of which can help minimize non-drilling time, and also measure while drilling logging technology (See page 29 for RCS explanation). Prospects for the new Atlas Copco Drilling Solutions model are good as the PV-235 enjoys the same level of success as its predecessors.

Dustin Penn

Blasthole Drilling in Open Pit Mining

Talking Technically

Development through interaction Single- or multi-pass drilling The large range Pit Viper 270 series drilling rigs provide 75,000 lbf (340 kN) force on bit and can be equipped for either rotary or down-the-hole (DTH) drilling. The automation platform for the Pit Viper series is the Rig Control System (RCS) and many PV-270 machines have been provided with RCS. The new PV-270 RCSseries is built with a new larger cabin and RCS-Basic as standard. The PV 270 series combine structural features of the PV-351, and components successfully used on the DM45, DM-M2 and DM-M3 models, and some new ones, including Tier II engine options. These features were incorporated as a result of extensive discussions with customers already using the Drilling Solutions equipment range

Low center of gravity Clearly an essential quality for this market is f lexibility, though the design engineering team could not ignore the across-the-board industry requirement for maintenance convenience and cost effectiveness. These two characteristics are evident from the PV-270 crawler tracks through to the choice of singlepass or multi-pass drilling. The PV-270 machines offer a choice of proven Caterpillar and Atlas Copco undercarriages to enhance their compatibility with other mine fleet members. The PV-271 is built with the extended version of either the CAT 345XL or the Atlas Copco GT3400, while the PV-275 can have either the standard 19-foot 6-inch (5.9 m) CAT 345XL with GFT110 final drive or the ACGT 3400 tracks. The design and testing process used for the PV-270 main frame was generally similar to that for the Pit Viper 351. To ensure long frame life without rebuilds, the I-beam used is 24 inches thick with a cross section of 162 lb./ft. – smaller than the PV-351 frame but

A PV-270 RCS-series used for blasthole drilling in an American mine.

larger than the one used on the DM-M3 rig. The structure achieves a low center of gravity for good stability and reduces drilling vibration. Single pass stability ratings, adjusted for dynamic conditions, are 5° with cab facing downhill and 8° tramming across the slope, both with tower up, and 10° with tower down, cab facing uphill. The equivalent multi-pass figures are respectively 11°, 13°, and 16°. The rigs also offer the customer a choice between a standard three jack configuration and four, with the rear jacks tied as on the Pit Viper 351.

Power options The power system setup for the PV-270 series machines is structurally similar to that on the Pit Viper 351 but includes a choice of matched engines and compressors suitable for the rotary or downhole drilling options. The engines offered, which are Tier II compliant, are the 760 hp (567 kW) Cummins QSK 19, the 800 hp (597 kW) Caterpillar C27, and the larger 950 hp (709 kW) Cater-pillar C32. There is a single side-by-side hydraulic/compressor/

radiator cooler package. The IngersollRand compressor options are a 1,900 CFM (900 l/s) unit or a 2,600 CFM (1230 l/s) supplying 110 psi (760 kPa), plus a 1,450 CFM (680 l/s) air compressor delivering air at 350 psi (2,400 kPa) for downhole drilling. The CAT C32 engine is fitted on those rigs using the 2,600 CFM compressor. The Atlas Copco patent-pending automatic hydraulic clutch, between the engine and the air end that was introduced during 2010 as a new option for the Pit Viper 235 series, is now available on the PV-270 series. The benefit of this clutch is that it will disengage the air compressor from the engine when the air end is switched off. In a traditional power package, the compressor consumes approximately 30% of its rated power at standby. Installation of this clutch eliminates fuel being used for this standby power consumption and allows for a low idle speed. While changing rods, levelling, or moving between the holes, the air compressor is disengaged allowing for horsepower savings during those cycles as well as increasing the service interval and life on the air compressor. The

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The PV-271 RCS is fitted with a larger cab. The computerized network rig control system (RCS) provides varoius levels of safety interlocks and automation.

The PV-271 live tower is dimensioned for 55-foot single-pass drilling, there is also a 65-foot clean hole single pass drilling tower option where a pipe must be racked when levering the tower.

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clutch removes parasitic engine loads at start up as the compressor is not engaged, therefore decreasing engine load and increasing engine and compressor life. The electric power pack option comprises alternatively a 700 hp (520 kW) WEG 6808 motor running on 6,000 V AC/50 Hz current and coupled with an 1,800 CFM/50Hz Ingersoll Rand air compressor, or a 900 hp (671 kW) WEG 6811 motor running on 4,160 V AC/60 Hz power that is coupled to the Ingersoll Rand 2,600 CFM/60 Hz air compressor. An electric powered version for downhole drilling is available for the PV-270 machines, albeit limited to 1,070 CFM and 350 psi for 50 Hz application. The motor is completely enclosed and is cooled by a fan with the highest rating in the industry, which allows the unit to operate without a machinery house. An oil-immersed nonflammable 40 kVA transformer protects the motor, providing 380 V AC for the extensive heating package used for all the reservoirs. The high voltage safety circuit and the operator controls run on 110 V AC that is converted to 24 V DC so that the electric machine can use the same components as the diesel-driven rigs. Experience shows that electric motors typically last 20,000 – 30,000 hours before replacement or rebuild in this application, as compared with the 10,000 – 14,000 hour life usually attained by diesel engines. This is one reason why there is growing interest in the electric Pit Vipers, to which Atlas Copco has also responded by matching the electric power pack to a mine’s available power supply. For example, four PV-275 rigs have been delivered to the Moroccan phosphates producer Office Chérifien des Phosphates (OCP) for operation at 5,500 V AC. Like that on the PV-351, the hydraulic system for the 270 series utilizes a leak-free, clean specification. However it has the single gearbox and three pumps configuration used on the DM-M3 rig, albeit with larger units; using fewer components has proved to reduce operating cost. There are two main pumps for feed, rotation and propel, while the double pump supplies the auxiliary functions. Blasthole Drilling in Open Pit Mining

Talking Technically

The PV-271 Rotary head.

The PV-271 RCS and PV-275 RCS are fitted with a new state of the art cabin, featuring visibility and comfort for the operator while undertaking complete machine control.

The air cleaners are similar to those on the PV-351, with one provided for the Cummins engine, two for the CAT, one for the 1,900 CFM air compressor and two for the 2,600 CFM unit. These and the other serviced units are easily accessed from the PV-270 deck, which is designed on similar lines to that of the PV-351, while retractable ladders are also available.

hole tower option, but with this unit one drill pipe must be racked and the rotary head brought down in order to lower the tower for relocation. Like the power pack, the variable displacement rotary head for the PV-270 rigs is very similar to the proven design used on the DM-M2 machine. The rotary head also has a filtered lubrication pump to keep the motor splines lubricated. Equipped with two motors, the 188 hp (252 kW) rotary head delivers up to 8,700 foot pounds (11.8 kNm) of torque. Maximum speed is 150 rpm. Internal spur gear speed reduction gives better torque on rough ground, and in other circumstances where the head stalls are later than other designs. The hydraulic rod support with automatic actuation is essentially the same as that proven on the DM-M3 rig. There is also an upper fixed rod catcher. Again like the PV-351, the Pit Viper 270 series drilling rigs use the cable feed system introduced on the DM-M3, however with some redesign to achieve faster feed speeds. The feed rate is 127 ft. /min. (38 m./min.) and the retract rate is 158 ft./min. (48 m./min.). The automatic tensioning is derived from

Three towers The two machines comprising the Pit Viper 270 series are primarily differentiated by their towers. These are of similar construction to those on the PV-351 but are new designs, not stretched or lighter weight versions of the existing design. The PV-271 live tower is dimensioned for 55-foot (16.7 m) clean hole single-pass drilling. Like the PV-351 it does have a two-rod changer, in this case for 25-foot rods enabling drilling to a total depth of 105 feet. With a four-rod carousel holding 40-foot pipe, the PV-275 is designed for multipass drilling to a maximum depth of 195 feet. There is also a 65-foot clean

the PV-351 system which has proved problem-free to date. The pipe handling system on the PV-271 is similar to that on the PV-351, and the PV-275 is similar to the DM-M3. The PV-270 series machines also use the same patented system for angle drilling as the Pit Viper 351, with 0 - 30° adjustment in 5° increments for the multi-pass PV-275 and 0 - 20° adjustment in 5° increments for the single pass PV-271. These rigs are quite widely used for angle drilling, both in coal mines and in metal mines for toe blasting.

Cab commonalitys There are two different cab options available for the PV-270 series. With the development of the RCS option, we have incorporated the new state of the art cabin into the PV-270 RCS machine design. While rigs without the RCS control system are fitted with the same single piece cab as that used for concurrent DM45, DML, and PV-270 machines. It meets the FOPS requirements of ISO 3449 Level 2, is thermally insulated and pressurized, and has adjustable vents for climate control. The

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air conditioning unit is side mounted, which, along with other detailed features, makes this cab easier to service so no roof access is required. The sound damping has been tested down to 70 dB(A) on the new cabin. The operator enjoys excellent visibility over the ergonomically designed wrap-around console. The controls are predominantly electric-over-hydraulic sticks.

Options As well as the four jack system, options available for the PV-270 series rigs when they were introduced included a dry dust collector with 9,000 CFM blower, four-camera system with LCD monitor, buddy seat, water injection, fire suppression, cold weather package, a central fast service system, high intensity Nordic lights, and a hydraulic test station (that is now standard). The integrated tower access ladder, a fall restraint system and an extended tower infill for accessing the tower for service and maintenance while it is in horizontal position is an available option. There is also an option for non-drill end tower access ladder, fall restraint system, and extended tower infill for accessing the tower while in horizontal position, as well as a number of ground level service options.

Rapid acceptance The Pit Viper 270 series rigs were rapidly accepted since its launch at MINExpo 2004. It was a machine that got it right in terms of all the parts working together perfectly, and customers seem to agree. In only four years the sales of the PV-270 series sur passed the accumulated 14-year sales record of its predecessor, the DM-M2. Barrick was one of the first mines to use a PV-271 at their Goldstrike operations, and the company now has nine of them. Newmont was another early customer, buying four PV-271 machines for the Yanacocha gold mine in Peru, and now has 17 of these rigs. Copper mining customers include FreeportMcMoRan which now has over 20 machines. Most recently, the PV-270 series has broken into the Australian coal and metals markets. 78

Pit Viper 271 working in a copper mine.

Many of the PV- 270 series rigs have been ordered for coal applications mainly in South Africa, Russia and the USA. The other major applications are in copper and gold, mostly in the Americas, and iron ore mines in Africa, Latin America, Russia and Ukraine. Almost all of the PV-275 machines are equipped for rotary drilling, but a significant number of the PV-271 units have ben configured for downhole

drilling, mainly single-pass drilling of 8-inch diameter holes at gold mines. Since the first PV-275 was shipped for testing at Peabody’s Kayenta coal mine in 2003 and the 2004 MINExpo launch of the new models, more than 250 units of the PV-270 series rigs have been shipped to customers.

Dustin Penn

Blasthole Drilling in Open Pit Mining

Talking Technically

The large Pit Viper 310 series Launched at MINExpo 2012 Following tradition, Atlas Copco Drilling Solutions extends its blasthole drills range at a fourth straight MINExpo. At MINExpo 2012 the company will exhibit both the PV-235 and a new rig, the PV-311, that is slated to be the first model in a new PV-310 series. Like the PV-351 this is a rotary rig set up for single-pass work, but able to drill deeper holes if required. However, it is a more compact machine designed to drill in soft and hard rock formations using a narrower range of large hole sizes – at the lower end of the PV-351 range and the upper side of the PV-270 models’ capability. As with the PV-270 series, the second model will be a multipass version – the PV-316.

Firmly family

The Pit Viper 310 series can drill a 65-foot clean hole in a single pass.

Market-driven, but staying with proven and preferred design concepts, the Atlas Copco Drilling Solutions team in Garland have developed the crawler-mounted Pit Viper range using an iterative process. These rigs have established a reputation for excellent performance and reliability and offer a full complement of state-of-the-art features. No surprise then that the new PV-310 series are conceptually and visually Pit Vipers. By utilizing a very high proportion of proven technology from previous Pit Viper series, trends of greater energy efficiency and safety continue. The standard undercarriage is an Atlas Copco 375 class extended unit, a robust frame and tower structural engineering and fabrication are similar to the previous models, along with four jacks. Once again, a choice of diesel or electric power supply is offered, as are Ingersoll Rand or Atlas Copco compressor model options. The fuel saving

automatic clutch introduced in 2010 for the PV-235 is also available as an option on the PV-310 series, and the hydraulic system again includes load sensing technology for auxillary uinctions. The hydraulic top-head drive drill rotation system that our Garland engineers have always preferred is retained. So is the automatically tensioned hydraulic cable feed, which is much lighter (and less noisy) than a chain feed system, which enables productiontime while maximizing “live tower” operation. Hydraulic powered break out tools are once more provided. The new large cabin is again insulated, pressurized, air conditioned and FOPS certified with high quality seating, and provides the operator with excellent visibility, touch screen and joystick controls. The computerized Rig Control System (RCS) is time proven, but, at the same time, remains sufficiently agile to support new developments in control technology.

However, size matters to both present and potential Pit Viper customers, so the new models bring to the marketplace a new combination of power and hole diameter/ hole depth ranges. The other key new features are a choice of diesel engines with Tier 4 compliance for those who need it and the even more spacious cab design.

Nimble versatility The first PV-310 series rotary blasthole drilling rig provides a maximum weight-on-bit of 110,000 lbf (490 kN), while the machine’s operating weight ranges from 310,000 – 340,000 lb (140,600 – 154,000 kg) depending on specification. The rig is 25 ft wide and is 98.5 ft long with the tower down. With the tower up it is 47 ft long (almost 6 ft shorter than the PV-351 and only 5 ft 9 ins longer than the PV-271). With the tower up the machine is 100.5 ft high, and 28.5 ft long when the tower

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Atlas Copco’s patent-pending clutch (left) is designed to significantly save on fuel costs. The new Atlas Copco heavy duty, high torque undercarriage. (right)

is down. The optional Caterpillar 350 custom undercarriage has a hydraulic propel system, hydraulic track tensioning, and a 162,000 lbf-ft (220 kNm) final drive. Alternatively, the standard heavy duty Atlas Copco 375 undercarriage can be fitted – as on the machine displayed at MINExpo. With this latter platform the power supply system provides a choice of two tramming speeds, either 1.0 or 1.6 mph, as on the PV-235. The main frame is made with wide f lange structural steel I-beam, like that on the PV-351, but with newly developed cross members designed to increase frame fatigue life. For the power pack frame the engineering team has used large rectangular tube that is very strong in torsion. There is a threepoint mount which prevents the transfer of torsion forces. The rig has four levelling jacks, each with a bore of 8 ins (203 mm)] and a stroke of 72 ins (1,830 mm). There are two staircase-type boarding ladders and tow hooks. The power pack may have either an electric motor or a choice of diesel engines. The two Tier 4 compliant engine options are the Caterpillar C32, rated at 1,125 HP/840 kW @ 1,800 rpm, or the MTU 16V Series 2,000 which 80

delivers 1,300 HP/970 kW @ 1,800 rpm. Alternatively, there is a choice of three Tier 2 compliant engines – the Cummins QSK 38 rated at 1,260HP @ 1,800 rpm , the Cat C32 rated at 1125 HP @ 1,800 rpm or the MTU 16V2000 unit delivering 1,205HP @ 1,800 rpm. The standard diesel fuel tank has a capacity of 700 U.S. gallons (2,650 liters) and provides sufficient fuel for 12 operating hours. It is normally teamed with a 1,200 U.S. gallon water tank. Alternative fuel/water tank combinations are 1,400 gallons and 1,200 gallons, providing sufficient fuel for 24-hour operation, or 700/1900 gallons which provides sufficient water if the rig is fitted with a water injection and dust collection option. Diesel machines also come with a ground level battery disconnect switch, battery equalizer and jump start hook up. The hydraulic system has the same main pump drive set-up as the PV-351 with P14 closed loop feed and rotation. But, like the PV-235, it has a load sensing piston pump serving the auxiliary units which increases machine efficiency. Load sensing should not only yield a reduction in fuel consumption but also deliver increased speed for auxiliary functions. As well as improving

life and cleanliness, it reduces the risk of system failure. The valve rack and I/O modules, together with the central hydraulic test station, are now located at one central station above deck. Hoses are tagged with a part number and reference number on both fitted ends and the reference number matches the hose number on the hydraulic schematic. The hydraulic oil tank has a capacity of 350 U.S. gallons (1325 liters). The required 3,000 CFM of compressed air at 110 PSIG (84.9 m 3/min @7.6 bar) can be supplied by either an Ingersoll Rand compressor with a 2 x 285 mm air end as used on the PV-351, or an Atlas Copco Twin S3 air end similar to the Single S3 available for the PV-235. The automatic hydraulic clutch – introduced as an option for the Pit Viper 235 during 2010 – has proved very beneficial. It disengages the air compressor from the engine when the air end is switched off; in a traditional power package the compressor uses perhaps 30% of its rated power when on standby. As well, this clutch allows for a low idle speed. The air compressor is also disengaged during rod changes, levelling, or moving between holes, so horsepower is saved during these cycles too. Blasthole Drilling in Open Pit Mining

Talking Technically

The PV-311 offers a dual acting hydraulic cylinder feed system that raises and lowers the rotary head by way of cable for pulldown and pullback, while integrating Atlas Copco’s patented cable tensioning system.

The engine and air compressor have separate air intake filters located at the non-drilling end of the machine. The filter rack has engine, compressor and hydraulic system filters. The cooling package, rated at up to 125°F (52°C), incorporates oil coolers for the hydraulic and compressor oils and an engine charge air cooler. One area of particular concern to mine engineering management is the speed and convenience of servicing and maintenance work. The PV-310 offers an optional 360° access decks with standard full deck service Fibergrate catwalks and railings, and there is 20 inches of service room between the power pack and the coolers. On the deck, hose and cables are located in trays as on the PV-235 and there are also dedicated runs in the frame with improved access. The fast service system provides ground level, quick connect fitting for filling and evacuation of fuel, hydraulic oil, engine oil, engine coolant and compressor oil.

Going deep The Pit Viper 310 series is designed to offer drilling flexibility. The tower

is an interchangeable unit structurally similar to that on the PV-351, but deeper in order to accommodate larger sheaves and to be suitable for use on both the single and multi-pass drilling versions. In addition, the weldments have been improved. When the tower is horizontal, a ladder from the deck provides access to decking in the tower above the rod changer. The new tower rest design allows replacement of a non-drilling end jack cylinder without removing the rest. Like the massive PV-351, the PV-311 model is set up for single-pass drilling 65 ft (19.8 m) clean holes, with bit changing above the deck. As with the larger machine, using the carousel’s two 35 ft (10.67 m) drill pipes, the rig can drill a maximum hole depth of 135 ft (41.1 m). However, the hole diameter range is quite different, 9-12¼ inch (229-311 mm), covering the upper sizes offered by the PV-270 models and the lower end of the PV-351’s hole size range. We anticipate the new model may particularly be used for single pass drilling 270 mm or 311 mm holes, depending on rock conditions. The upgraded and well proven twospeed hydraulic motor rotary head, already used for the DM-M3, provides

drill rotation. It delivers 13,800 lbf-ft (17.5 kNm) rotation torque at 140 rpm And 7,500 lbf-ft at 240 rpm. Hydraulic pulldown is 100,000 lbf and pullback is 50,000 lbf. Hydraulic cylinders drive the cable feed system, which has the patented Atlas Copco Drilling Solutions automatic tensioning of the pulldown and pullback cables. The auto-tension power screw is like that on the PV-351, the tension cylinder as on the PV-271 but with a larger diameter rod, and the valve and hydraulic design is as per the PV-235 which extend cable life. The thread greasing system uses a electric driven pump similar to that on the PV-270 series and PV-235 rigs. There are improved rotary head guides and, as on the PV-351, rod support is provided when the head is close to the top of the tower. The carousel works with a “no-bump” rod changer and there is an 8,000 lb (3,630 kg) capacity auxiliary hoist for handling rods. The breakout tools are those now standard across the Pit Viper range. There is a hydraulically powered breakout slide wrench, the fork chuck having an improved deck bushing, and a handsfree auxiliary hydraulic wrench with a 6-inch clamp cylinder. Dust curtains are hydraulically retractable.

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The PV-311 offers a spacious cab, as well as maintenance friendly enclosed filter rack and ground level service access.

The drilling angle can be varied in 5° increments from 0-20° on the PV-311 and 0-30° on the PV-316.

In control, in comfort, in safety The PV-310 series continues our quest to provide the rig operator with every facility needed to achieve maximum machine productivity all shift long. Designed with assistance from the Atlas Copco Rocktec team in Sweden, the cabin is larger than that used on the PV-351 (or any other Atlas Copco Drilling Solutions rig) and has been further improved over the PV-235. In conjunction with the elevated cabin, three large tinted windows on three sides, each fitted with windshield wipers and washers, give excellent visibility from the operator’s suspension seat. The Atlas Copco Rig Control System (RCS) display and joystick controls are integrated with the seat. The backlit electrical cabinet has been integrated to provide easy, secure access and the size has been increased to provide flexibility for changes in the electrical specification during the rig’s lifetime. There is a buddy seat installed on the front-left side of the cab, and both the buddy seat and the operator's 82

suspension seat come installed with retractable seat belts. The operator's seat and buddy seat are both installed with retractable seat belts. While the work surface above the spaces for the optional refrigerator and microwave can seat other visitors; during the rig build the cabin has hosted up to 10 people. The air conditioning system has 12 kW of cooling power that includes a hydraulic compressor and a condenser fan that reduces overall machine electrical requirements. For operation at night, a High Intensity Discharge (HID) lighting package and a cabin dome light are standard. The rig’s presence is indicated by LED strobe lights, amber on the cab and blue on the tower. Elsewhere there are the usual emergency shut-down buttons, propel alarm, attention horn and ground level cable for horn activation.

Options As well as the Atlas Copco 375 undercarriage, engine and fuel/water tank options there are other additions or alternatives available to suit operators’ specific circumstances. These include: an engine enclosure similar to that introduced with the PV-235, a wraparound cabin deck, hydraulic boarding

ladders, a water injection and dust collection system, an LED lighting package and a fire suppression system that can be mounted on the non-cab side of the tower. In addition to a number of standard safety and interlock features, the RCS Basic control system can offer a series of options – Autolevel, Autodrilling, GPS hole navigation, Desktop Viewer and communication, wireless remote tramming, Measure-While-Drilling data log files, and the International Rock Excavation Data Exchange System (IREDES).

Multi-pass drilling Development of the PV-316 multi-pass drilling model is well advanced. On this rig the tower will allow drilling to a depth of 295 ft (90m) using a five-rod carousel with 50 ft (15.25m) drill pipe. This is a substantial increase over the PV-275, which offers multi-pass drilling to 195 ft (59.4 m)*. The PV-316 is expected to be launched during 2013 and to replace the DM-M3 model. *For full Pit Viper 311 data see Specification page 207.

Dustin Penn Blasthole Drilling in Open Pit Mining

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Large diameter drilling Pit Viper 351 The giant Pit Viper 351 is a flexible rotary drill rig with a weight on bit of 125,000 pounds (56,700 kg), and the ability to drill 10 5/8 -inch to 16-inch (270-406 mm) diameter holes to a maximum depth of 135 feet. However, at MINExpo 2000 many customers commented: “It’s set up to single-pass drill a 65-foot-deep hole.” The PV-351 is ruggedly constructed with an operating weight of 385,000415,000 pounds (175-188 tons). However, it takes only touch screen controls and a joystick to operate.

Power platform From the ground up, the PV-351 is a robust and highly capable drilling rig. The undercarriage is a hydraulically driven custom version of the Caterpillar 385 excavator unit. At 26 feet 10 inches (8.18 m) in length this is the largest undercarriage used for a rotary drilling rig. Maximum tramming speed is 1.1 mph (1.77 km/h). The main frame was designed using finite element analysis and was subjected to dynamic strain gauge testing. To ensure long frame life without rebuilds, the I-beam used is 30 inches thick with a cross section of 326 lbs/ft It supports three inboard mounted tanks – one 900 gallon (3,407 liter) water and two 600 gallon (227 l) fuel, as well as the forward jacks and rear tower support and jacks assembly. There are four levelling jacks with 10 inch (254 mm) bore and 72 inch (1,829 mm) stroke. The rear jacks are cross linked to minimize frame twisting. Power for the multiple hydraulic systems and air compressor used on the PV-351 comes from either a diesel engine or an electric motor. Either drives the hydraulic power pack via a drive shaft and the air compressor directly. A floating power pack sub-base isolates the components from vibration. Two coolers allow operation up to an

The diesel powered PV-351 can be offered with Cummins or CAT 12-cylinder engines.

ambient temperature of 125°F (52°C). Two 12-cylinder diesel engines with electronic monitoring systems that meet the EPA Tier I standard are offered; the Cummins QSK 45, rated 1,500 hp (1,119 kW) at 1,800 rpm, and

the Caterpillar 3,512, rated at 1,650 hp (1,230 kW) at 1,800 rpm. The 1,400 hp (1,044 kW) electric power unit comes with a rear access platform and, optionally, a 1,500 ft (457 m) capacity cable reel for a 2 inch (51 mm)

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Pit Viper 351 “live” tower.

Weg motor – 1400 hp.

cable. The WEG 6811 squirrel cage motor normally runs on a 50 or 60 Hz, 4,160 – 7,200 V AC power supply. The machinery house for the electric unit, containing the majority of the main components, is hydraulically pressurized and has two access doors and removable roof panels. Some 80–85 percent of the components used in the rig are the same in the diesel and the electric versions. The hydraulic system has a 350 gallon (1,325 l) tank with three-micron filtration. To ensure reliable operation, the designers made extensive use of hard piping with Stauff clamps for hoses, O-ring face seal fittings and two quick change filters. There is a single gearbox and five pumps. The main Parker Denison variable displacement pumps control the propel motors and drill feed/rotation. Other pumps run various auxiliary functions. The use of integrated circuit blocks reduces the number of hose connections. The well proven Ingersoll-Rand asymmetrical screw compressor features twin rotors in parallel, variable volume electronic control and lubrication pumps that minimize load during startup. It delivers up to 3,800 CFM (107.6 m 3/ minute) of air, which is the highest rate ever available on a blasthole drill. At 110 psi (758 kPa), it´s a pressure that ensures improved bit life. The air cleaners employ an innovative three-stage system in which the elements are easy to access and easy to change. Quick release co-vers make for easy operator maintenance. The PV-351 is designed to be a maintenance friendly machine. The superstructure is laid out to allow safe, easy movement and good access to service points. The rig has standard Wiggins Quick Fills for programmed maintenance and daily refilling. The spool valves are located above the deck and all the filter elements are easy to reach. The standard decking to the rear of the tower and the tower access ladder enable service personnel to inspect the rotary head and other tower components while the tower is down.

Versatile tower Valve stand offering excellent accessibility for maintenance.

84

Like the main frame, the tower for the PV-351 was designed with the aid of

finite element analysis and tested by dynamic strain testing. The tower is of open front construction, fabricated by certified Drilling Solutions welders using rectangular steel tubing, and has four main vertical members. The design retains the unique “live” design used for the Drillmaster towers, which enables the operator to raise and lower the tower with the rotary head at the top and the rods in place; a capability that typically saves 4 – 10 hours of work when moving a rig. The tower is dimensioned for drilling 65 feet (19.8 m) in a single pass. Using a longer starter rod, the operator can drill 70 feet (21.3 m) in a single pass but the tower cannot be used live. There is also a two-rod carousel with key lock retention for a 35 ft (10.7 m) long and 8⅝-inch to 13⅜-inch (219 – 340 mm) diameter drill pipe, so the PV-351 can drill to a depth of 135 feet. Drill rotation uses the hydraulic drive rotary head system that the Garland team has preferred to an electric motor drive for a long time. It is the compact size and light weight of this design that makes possible “live” tower operation of the PV-351 and preceding Drillmaster rigs. The variable displacement rotary head on the big Pit Viper has two 14cubic inch motors that deliver 340 hp (254 kW) and a maximum torque of 19,000 foot-pounds (25,759 Nm). Maximum speed is 170 rpm. Simply adjusted extended head guides maintain alignment during descent and a separate lube pump improves motor spline life. A rod support system, actuated automatically by detection points at the rotary head, supports the pipe at its mid-point whenever the rotary head is near the top of the tower. Another important feature of the Atlas Copco Drilling Solutions rig design is the patented cable feed pulldown and pullback system developed in-house and introduced on the DM-M3. It is low-cost, four times lighter and much quieter than a chain feed, but offers good buckling resistance. The cables absorb the loads transmitted by drilling before they reach the rotary head so that drilling is smoother and bit wear is reduced. As well as providing 120,000 pounds (54,446 kg) of pulldown and 125,000 pounds (56,700 kg) of bit load, the dual Blasthole Drilling in Open Pit Mining

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The variable displacement rotary head and the automatically actuated rod support.

Automatic cable tensioning – pull-down cables jack screws.

The optional cable reel for 1600 feet of 2-inch cable.

cylinder system delivers 70,000 pounds (31,752 kg) of pullback and retract speed is 140 FPM (42.7 m/min). The system also improves rig safety as the operator can detect dangerous amounts of wear, whereas a chain feed can fail catastrophically. The downside is that stretching in use results in a loss of cable tension, but this has been countered by an automatic tensioning system that uses independent hydraulic motors and jack screws to tension the pulldown cables and hydraulic cylinders to tension the pullback ones. The system maintains tension, ensuring accurate rotary head alignment, and eliminates maintenance hours for tensioning. The break out system may not be the most technically sophisticated piece of equipment on a rotary drilling rig, but from the operator’s point of view, its effectiveness is very important in terms of the physical effort required and the non-drilling time involved. On the PV-351 primary break out is achieved simply and effectively by a sliding fork and reverse rotation. A patented self-adjusting hydraulic tong wrench, already proven on the DM-M3 rigs,

is used for auxiliary break out. Neither operation transmits shock loads to the tower. The PV-351 has a patented system for angle drilling between vertical and 30° in 5° increments. The same system is used on the DM-M3 rig. There is a short, independently supported pivot point and hydraulic cylinder at the base of the tower, and two telescoping rear legs are attached to the tower close to the rotary head’s uppermost position and to the tower rest at the rear of the rig. Locking pins are remotely activated. This configuration allows the tower to pivot at deck level, minimizing the amount of unsupported drill pipe, which gives the operator a better view of the deck. The hole to be drilled can be collared within the Pit Viper’s dust hood.

New generation cab The new large operators cab is the same as the one designed for the Pit Viper 310 series, and has been further improved over the original PV-351 cabin. In conjunction with the elevated cabin, three large tinted windows on

three sides, each fitted with windshield wipers and washers, give excellent visibility from the operator’s suspension seat. The Atlas Copco Rig Control System (RCS) display and joystick controls are integrated with the seat. The electrical cabinet has been integrated to provide easy, secure access and the size has been increased to provide flexibility for changes in the electrical specification during the rig’s lifetime. There is a buddy seat installed on the front-left side of the cab, and both the buddy seat and the operator's suspension seat come installed with retractable seat belts. The air conditioning system has 12 kW of cooling power that includes a hydraulic compressor and a condenser fan that reduces overall machine electrical requirements. The PV-351 is equipped with the Atlas Copco computerized Rig Control System (RCS). RCS is time proven yet remarkably agile to continually support current technology advances. Based on the highly reliable and well proven CAN-bus (Controller Area Network) system, RCS uses a single main cable through the rig intercon-

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Inside and outside view of the new PV-351 cab. The RCS control system provides a number of safety and interlock features and a series of automation options.

necting a series of modules controlling the drill’s sensors and actuators. This simplistic modular design allows upgrades to higher levels of automation with little machine downtime. The RCS touch screen displays a selection of data, including all pertinent drill information using internationally recognizable symbols. The screen is not affected by dirt and can be used by operators wearing gloves. The PV-351 rigs being supplied to Boliden’s Aitik copper mine in Sweden are equipped for Remote Rig Access, enabling Atlas Copco to check the drilling performance, maintenance requirements, etc. from distant locations. Aitik already uses this technology to good effect for other major equipment units. This includes the RCS (Computerized Rig Control System page 29), GPS positioning, MWD (Measurement While Drilling) data collection functionality, Autodrill, Auto levelling and wireless data transfer.

Options A number of equipment options are available for all the Pit Viper models. These include fire suppression systems and computer-controlled central lubrication. Specific options developed for the PV-351 include a cold weather package 86

for operation in ambient temperatures down to -40° C, a four-camera LCD vision system and attention horn, and a wireless remote propel control. Remote controlled tramming with the operator off the rig is mandatory in certain situations under some regulatory authorities. Additional options are a Hiab crane for loading and unloading bits and accessories, hydraulic retractable staircase, tower ladder and much more. Optional equipment for electric Pit Vipers includes a 5-by-8-foot cable reel for 1,600 feet of 2 inch cable, a load break switch, a power factor correction system, a machinery house pressurizer, and a 2,100 gal (7,950 l) water injection system.

Extensive experience It is now almost 12 years since the first PV-351 started drilling at the then Phelps Dodge Morenci copper mine. A second field follow machine went to Northgate’s Kemess mine in May 2003. Atlas Copco decided to invest considerable amounts in production facilities, and this enabled the Drilling Solutions division to step up marketing efforts as mining industry investment in new equipment began to increase.Commercial deliveries of the Pit Viper started in 2005-6 and the first PV-351 units headed south to Codelco’s Chuquicamata

copper mine in Chile and to the Anglo Platinum Potgietersrust operation (now called Mogalakwena) in South Africa. Codelco reported excellent results with the first machine and ordered a second rig that arrived at Chuqui in September 2006. Soon after, another PV-351 started operating at Codelco’s Radomiro Tomic mine and Andina ordered electric powered machines. The first two PV-351 rigs at Anglo Platinum now have a fleet of nine electric machines. There are now PV-351 fleets working for Vale at Sossego in Brazil, at the Penasquito precious metals mine in Mexico, and at the Los Pelambres and Spence copper mines in Chile. Antofagasta chose a mix of diesel and electric rigs for Los Pelambres and Rio Tinto has done the same at the Rössing uranium mine in Namibia, southern Africa. Antofagasta minerals has invested in electric PV-351 units for its Esperanza project in Chile, while BHP’s Escondida mine is building up a fleet of diesel PV-351’s. A fleet of machines are operating at Newmont’s Batu Hijau mine in Indonesia and Atlas Copco has also supplied 5 PV-351E drilling rigs to Boliden in Sweden for their Aitik 36 project.

Dustin Penn

Blasthole Drilling in Open Pit Mining

Talking Technically

The economic case for routine bit grinding Cutting hole costs The button bit was originally developed to do the job of an insert bit, without any grinding at all. However, it was soon found that the service life of a button bit increased considerably if the cemented carbide buttons were ground.    Nowadays, it has become extremely important to grind button bits at proper intervals, in order to extend the service life of the rock drilling tool, maintain penetration rates, and drill straight holes.    In all rock excavation operations, the cost is usually ex­pressed in cost per drilled metre (cost/dm), in cost per cubic metre (cost/m3), or in cost per tonne.    The cost to produce a hole depends on how fast it can be drilled, and how many tools will be consumed. The cost to produce a cubic metre of rock is dependent upon the cost of the hole, and the cost of blasting. If the blasthole is of poor quality, then more explosives will be consumed in blasting the rock. Unsharpened bits very often give a poor quality hole with deviation.    Grinding constitutes around 2% of the costs of the entire drilling operation. To run the business without grinding could multiply this cost, with up to 100% added when production losses are taken into account. Labour and material are the highest costs, while the machine investment cost is low when ­u tilization is high, with a large number of bits to be ground.

The Secoroc BQ3 grinding machine can handle drill bits up to 127 mm in diameter.

700

throughout its life, maintains the correct button shape and pro­t rusion. It features correct centring on all buttons, producing a high quality cemented carbide surface, with no risk of cemented carbide nipple. Long bit life, and higher penetration rates, will result from good grinding quality. Disadvantages of using the grinding cup are that it may produce an incorrect button shape and protrusion, and a lower penetration rate. It is difficult to centre the grinding cup over the gauge button, and there is also a risk of producing a sharp cemented carbide nipple on the button. Reduced bit life will result from poor grinding quality. Several tests have been carried out to find which method gives the best bit performance. The grinding wheel gives the correct shape to the button, regardless of the amount of wear on the wheel, ensuring that the bit will achieve standard penetration rate throughout its

Total bit life drill metres

600

10 regrindings per drill bit

500 400 300

Grinding methods There are two different methods of bit grinding to restore the buttons. The preferred method uses a diamond coated profiled wheel, and the other, a grinding cup. The profiled wheel provides a smooth​ ​and efficient grinding oper­ation, which,​

200

Grinding interval drill metres

100 0

10 20 30 40 50 60 Diagram 1: Typical bit life grinding at different intervals.

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third of the button diameter. When the number of drilled metres to reach this stage has been established, then a calculation of bit life can be made, by multiplying by the number of times it can be reground. As a general rule, a bit can be reground 10 times, but smaller bits may achieve slightly less than this figure, while larger bits may achieve more. So, if the grinding interval has been established as 60 drill metres, then the bit life can be 660 drill metres (diagram 1). If a bit is overdrilled, and the wear flat is more than half of the button diameter, there is a tendency towards cracked buttons.T here is always a sharp edge created on the button, and this becomes sharper the more the bit is overdrilled. This sharp edge, especi­ally on ballistic buttons, is very brittle. Once the edge cracks, pieces of cemented carbide break away and circulate in the hole, causing secondary damage to the buttons. When a bit doesn’t show any visible wear and the buttons are shiny like a mirror, it may be suffering from micro cracks on the cemented carbide surface. This is known colloquially as snakeskin, and can be clearly seen when using a magnifier. In this case, the surface has to be ground away, otherwise the micro cracks lead to more severe damage on the buttons. Likewise, buttons which protrude too much must be ground down to avoid damage (diagram 2).

Diagram 2: Risk of total loss when a bit is overdrilled.

Penetration rate

Diagram 3: Penetration rate drops as the button profiles flatten.

entire life. It has also been shown that bit life is increased considerably when grinding wheels are used, rather than grinding cups. Wheels also excavate steel around the button, simplifying the grinding task, and giving the bit a more exact profile. 88

Bit life With so many parameters involved, it is difficult to estimate bit service life. First, a proper grinding interval must be established, preferably at the stage when the button has a wear flat of one

When the right bit has been chosen for the rock condition, it will provide maximum penetration rate, along with acceptable hole straightness. In rock conditions like Swedish granite, with a compressive strength of around 2,200 bar, the bit gets a wear flat after just 10-20 drill metres, accompanied by a small drop in penetration rate. When it has a wear flat equivalent to one-third of the button diameter, the penetration will have dropped by 5%. If the bit is used further until it has a two-thirds wear f lat, the penetration will have dropped more than 30% (diagram 3). When a bit has a heavy wear f lat it tends to deviate, and, by the time it reaches the bottom of the hole, it will Blasthole Drilling in Open Pit Mining

Talking Technically

stress on the remaining rock tools in the drillstring. A sharp bit always cuts better, and will prevent both deviation, and its disadvantages.

Grinding machines

Secoroc Manual B.

have deviated far more than planned. As a result, the blast will produce coarse fragmentation, and much secondary blasting may be required. In slope hole drilling, it is of utmost importance that the holes are straight. If the holes deviate, the slope walls will be uneven, making rock reinforcement more difficult than expected. Rock formations with different layers and joints are often characterized by heavy hole deviation, putting extra

Two parameters guide the selection of the right grinding machine: the number of bits or steel to be ground; and whether the machine should be portable or station­a ry. Several kinds of grinding machines are available to satisfy these parameters. In most cases, a simple machine will suffice for a small operation, grinding only a few bits. The semi-automatic machines are more suitable for larger operations, such as mines and construction sites, where the machine can be stationary, and the rocktools can be brought to it. Secoroc HG is a water or air-cooled handheld machine for grinding cups. Both spherical, ballistic and steel cutting cups are available. The machine is driven by up to 7 bar compressed air, and is suitable for a small grinding operation. Secoroc Manual B is an air-driven portable grinder using diamond-coated grinding wheels for spherical, ballistic and full-ballistic buttons. The machine is mounted in a box fitted with wheels and handles for easy set up. This is made for threaded button bits. A steel spring is mounted in the profile of the

grinding wheel, where it functions as a centring device, allowing for easy grinding. Secoroc Manual B-DTH is similar to the Secoroc Manual B. It is mainly intended for DTH bits and COPROD, but can also be used for threaded bits with a special bit holder. Secoroc Jazz is a very flexible grinder that can grind both threaded, tapered, DTH- and COPROD bits, in spherical and ballistic versions. The hole range is from 35 mm to 254 mm. Secoroc BQ3 is the latest semiautomatic machine, with many features such as more efficient working light, better cooling nozzle, soft start of grinding table, water filter, sleeve coupling for ventilation plus all features the previous version had. These features, coupled to an ergonomic design, ensure high productivity, and the machine is designed to handle large volumes of threaded button bits. Cooling water is recycled after the waste product has been separated in a container. Secoroc BQ3-DTH is the latest grinding machine for mainly DTH and COPROD bits. It can also be used for threaded bits with a special bit holder. The machine has the same features as Secoroc BQ3, and can grind bits up to 178 mm (7 in) diameter. Secoroc Senior and Swing are grinders for integral steel.

9 8 7 6 5

Labour cost

4

Grinding material cost

3

Machine cost

2

Annual grinding volume – buttons.

1

Figures on the left side of the diagram show cost per button in SEK. 100 000

75 000

50 000

25 000

10 000

5 000

0

Cost of grinding reduces dramatically with volume.

Diamond grinding wheels.

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Secoroc Manual B-DTH.

Secoroc BQ3-DTH.

Grinding advice The Secoroc grinding machine’s secret of success is that both the grinding table and the diamond grinding wheel rotate. The result is perfectly ground button surfaces, regardless of whether the buttons are spherical, ballistic or full-ballistic. In addition, the machine’s unique diamond grinding wheel is designed to ensure even wear on its grinding surface, while still retaining its profile. This, in turn, guarantees the button shape throughout the life of the wheel. Secoroc’s advice is to use Secoroc grinding machines, with profiled diamond grinding wheels, for grinding button bits. It is the only solution able to consistently deliver perfectly shaped buttons on customers’ bits, which gives longer service life to all rock drilling tools, rock drills and drill rigs. Correct grinding is important for every drilling operation, particularly in these days of cost consciousness and fierce competition. It can make a world of difference to the bottom line.

Bo Persson

Comparison of grinding wheel with grinding cup.

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Blasthole Drilling in Open Pit Mining

Talking Technically

Secoroc Jazz

Secoroc Jazz for correct and professional grinding.

Rig mounted grinder In today’s world of professional rock drilling, where ever more powerful drill rigs and hammers are used, it has become extremely important to give the drill string all the necessary care and maintenance needed if optimum drilling productivity is to be achieved.    Regrinding the cemented carbide buttons of the bit at proper intervals increases the service life of the whole drill string. This, in turn, helps maintain penetration rates, while ensuring that holes are drilled straight and true.    Quick and efficient grinding of button bits in surface drilling applications, where the rig is constantly on the move from one job site to another, has been an elusive goal. However, Atlas Copco Secoroc has now come up with the solution, by developing a rigmounted semi-automatic grinder. The Secoroc Jazz, equipped with a profile d diamond grinding wheel, achieves the same quality of grinding onboard the rig as that previously associated with static workshop models.

Blasthole Drilling in Open Pit Mining

Development Atlas Copco Secoroc has gained extensive knowledge and experience of regrinding large volumes of button bits with stationary grinders, such as the Secoroc BQ3 and Secoroc BQ3-DTH. These, toge​ther with previous generations of similar grinders, have all used profiled diamond grinding wheels for working on spherical, ballistic and fullballistic buttons. However, onboard grinding machines have always been fitted with diamond grinding cups, which have proved to be less efficient than profiled diamond grinding wheels. The new Secoroc Jazz grinder, which is equipped with profiled diamond grinding wheels, will consistently deliver the same perfectly shaped spherical and ballistic buttons after regrinding. This is increasingly important in relation to ballistic buttons, which are becoming more and more popular.

Secoroc Jazz The air-driven Secoroc Jazz helps optimize the performance of the rock drill and drill string, ­without the bit leaving the rig. It is user friendly, is designed

for economy of air consumption, and can easily be retro-fitted to most rigs in current use. It is delivered with an attachment for bolting on to existing rigs, which allows the operator to fold away the grinder when not in use. It will also be available through the sales companies as an option on new Atlas Copco drill rigs. To make the grinder ready for work, it is simply a matter of hooking up the air hose, connecting the electricity, and filling up the water tank for the mist cooling. The low air consumption of the Secoroc Jazz makes it possible to grind bits without interrupting drilling operations. The grinder is semi-­automatic, and features an automatic centring device for placing each button in the correct position under the grinding wheel. An indexing bit holder is used for the gauge buttons, and there is a handy time relay for setting grinding time. Secoroc Jazz is a very flexible grinder that will have a beneficial influence on drilling economy. It will grind spherical and ballistic buttons, on threaded or tapered button bits, as well as big DTH - and COPROD bits from 35 mm (13 ⁄8 in) to 254 mm (10 in) in diameter. 91

Talking Technically

Grinding instructions for button bits When to regrind

Button bits should be reground when the penetration rate drops, or if any of the cemented-carbide buttons are damaged (fractured buttons should be ground flat). It is both practical and economical to redress the buttons when the wear flat reaches about 1/3 of the diameter of the button.

Look out for “snake skin”

If microscopic fatigue cracks – so called “snake skin” – begin to appear on the cemented carbide buttons, the cracks must be ground away. In any event, bits should be reground after 300 metres of drilling at the most.    This should be done even if there are no visible signs of wear and the penetration rate continues to be good. If snake-skin is not removed, the cracks will deepen and ultimately result in button fracture.

Do not grind away too much cemented carbide

Secoroc Jazz can easily be set up on the drill rig, here the machine is ready for grinding. Do not grind too much on the top of the buttons. Let a few millimetres of the wear flat remain on top of the button.

Always grind broken buttons flat

A drill bit can remain in service as long as the gauge buttons maintain the diameter of the bit. Fractured buttons must always be ground flat to prevent chips of cemented carbide from damaging the other buttons.

Avoid grinding the gauge

1 Gauge button anti-taper has to be removed by grinding, although excessive reduction of the bit diameter should be avoided. Leave about max 1 mm of the wear flat.

Grinding the button bit in a professional way makes sense, because grinding accounts for only a fraction of the cost of the entire drilling operation. When a drilling programme is carried on without correct service of the bits,

drilling output and produc­t ivity will be significantly lower, and costs may escalate.

Bo Persson

Secoroc Jazz

Technical Data Air pressure, maximum

7 bar (102 psi)

Air pressure, minimum

6 bar (87 psi)

Air consumption

25 l/sec

Coolant container

3l

Air tool oil consumption

1.8 cl/hour

Output, spindle motor

1 kW

Speed, spindle

15,000 rpm

Voltage

24 V (D.C.)

Weight, exclusive of packing

90 kg (198 lbs)

Transport dimension

800 x 500 x 700 mm

Grinding Capacity

If necessary, remove some of the bit-body steel below the gauge buttons, so that a clearance (taper) of 0.5 mm is maintained. If the flushing holes start to deform, open them up with the aid of a rotary burr or steel file.

92

Maximum distance between bit holder and grinding wheel

250 mm (9 7⁄8")

Maximum diameter of drill bit

254 mm (10")

Minimum diameter of drill bit

35 mm (13⁄8")

Minimum distance between buttons

3.5 mm ( 9⁄64")

Blasthole Drilling in Open Pit Mining

Sweden, gällivare

Aitik eyes top three efficiency

The Aitik 36 project has increased ore production, and has put Aitik on pace to reach 36 Mt/y by the end of 2012.The investment will make Aitik one of the most cost-efficient mines in the world.

Boliden on course With the Aitik 36 expansion completed in 2010 mining is now scheduled to continue until 2029. The latest technology including Atlas Copco Pit Viper and SmartROC drilling rigs is helping Boliden to double concentrator throughput of low-grade copper ore and deliver a competitive concentrate to its Swedish smelting and refining complex.

High-tech strategy Since 1968 Boliden AB has sought to supply a competitive copper and precious metals concentrate to the Rönnskär smelting and refining complex at Skelleftehamn, from the Aitik open pit mine. The company has periodically

upgraded the mining and treatment of low-grade ore to maintain financially viable production. In 2010 the Aitik 36 Project was completed, extending Aitik’s mine life from 2016 to 2029. Drill Supervisor Nils Johansson is optimistic for the future. The new plant is a big reason for the large increase in production, and Nils Johansson says that 45 million tonnes can easily be handled by the new processing plant. The only work to be done is to coordinate the waste and the rock. Acting Mine Manager and Drill Superintendent Supervisor Peter Palo also emphasizes the increase in production: “We’re looking forward to produce 45 million tons of ore and 45 million tons of waste. That’s the next step. The earliest will be in five years.” As with previous expansions at Aitik, Boliden has opted for the most cost effective appropriate technology

available: one result was the mine’s expansion included adding four Atlas Copco Pit Viper rigs to the production drilling fleet.

Securing copper supply Located near Gällivare and 60 km north of the Arctic Circle, Aitik rails material 400 km to Boliden’s Rönnskär complex at the Baltic port of Skelleftehamn. It is the facility’s largest copper concentrate supplier although Rönnskär treats a range of concentrates and scrap to yield refined copper, lead, precious metals and zinc clinker. The company operates four more primary metal production facilities and is the third largest copper and zinc metals supplier in Europe. In 2006 Boliden concluded that, whereas the existing 18 Mt/y operation was scheduled to close in 2016, a new

Blasthole Drilling in Open Pit Mining 93

Aitik eyes top three efficiency

Boliden undertook a thorough evaluation before deciding to invest in four new Pit Viper 351 rotary drill rigs. Boliden’s criteria included the ability to drill 311 mm holes to a depth of 19 meters.

state-of-the-art and larger scale concentrator would be technically and economically able to continue recovering concentrate from significantly lower grade ore reserves at Aitik. The available tonnage would allow Aitik to process 36 Mt/y by 2014 and continue production until 2029. Concentrate sh ipment to Rön nskä r could be improved by building a rail spur from the mine site to the main line instead of trucking the material to the station at Gällivare. The €600 million ($845 mn) Aitik 36 Project was launched in 2007; the new transport and processing systems came fully on-stream in April 2010 and the official opening by King Carl XVI Gustaf was held on August 1, 2010. The mining operation in Aitik is based on proven and probable reserves of 710 Mt. As of December 2011 proven reserves totaled 486 Mt, grading 0.25% copper, 0.15 g/t gold, and 1.6 g/t silver, while probable reserves were 224 Mt. Although the grade is low, Aitik does get a little help from nature due to the good rock conditions that enable’s the mine to have really steep slopes – 47° 94

on the footwalls and 52° on the hanging wall. This means they don’t have to mine too much waste rock. For the Life of Mine the waste-ore strip ratio is as low as 0.5:1. To achieve the required ore extraction rate the Aitik 36 project team decided to cut back the pit boundary in a number of places and to mine down to 600 meters. A supplementary open pit has been developed at Salmijärvi, one kilometer southeast of the main mine. Currently, Salmijärvi is at 60 meters depth with plans to reach 210 meters depth in approximately 10 years. Nils Johansson said, “Today we’re mining the southern part [of the mine] for ore and the northern part for waste, heading for ore. And then there are two levels active in Salmijärvi as well, so we have two main fronts and two secondary fronts." In all more than 80 Mt/y of rock will be moved and Aitik 36 included a largely new in-pit crushing and conveying system to contain mine site rock haulage costs as well as additional new shovels and trucks. Boliden undertook a thorough evaluation of available

Top: Nils Johansson, Drill Supervisor. Bottom: Peter Palo, Drill Superintendent and acting Mine Manager.

options in 2007 and decided to continue primarily with electric-powered equipment. Loading and haulage capacity would be raised by buying new models from the suppliers of the existing fleets. But the drilling rigs evaluation persuaded Boliden to switch suppliers.

Drill fleet build-up Aitik’s primary blasting requirement is to produce a fragmentation suited not only to the loading, hauling, crushing and conveying equipment but also to the grinding system Boliden favors. They’re doing so using auto-genous milling, which means it’s important to get the drilling and blasting right. The blasthole drilling effort at Aitik has been shared between Boliden personnel doing the bench production drilling and an NCC team contracted to do the pre-splitting. Aitik chose to retain this division of labor so NCC was able to continue using its Atlas Copco ROC L8 machines for downhole drilling straight contour holes. Boliden, on the other hand, needed to upgrade their fleet of large rotary drill rigs with four Blasthole Drilling in Open Pit Mining

Aitik eyes top three efficiency

The PV-351, installed with RCS, offer features like finger-tip joystick controls, a comfortable cabin, ability to drill angled holes, and ease of raising and lowering the tower for tramming.

new units. The project team’s primary criterion was the ability to single pass drill 311 mm diameter holes to a depth of at least 19 m: drilling big 311 mm holes going 16 to 17 m deep eliminates the risk of deviation, points out Peter Palo, Boliden’s acting mine manager and development superintendent. Also extremely important for the fragmentation is the positional accuracy of each hole; the more accurate the holes, the wider the pattern can be. That way Aitik can actually save drill meters and drill fewer holes. Ability to drill the right hole depths is also important, with smooth blasting to yield good flat surfaces for the large loaders and trucks. Drilling to the right depth also means there will be less loose rock to drill through on the next level down. Consequently, the team looked for features such as finger-tip joystick controls, programmable automatic drilling modes and GPS-based hole navigation. Other major considerations were good built-in safety and productivity enhancing features such as an operator-friendly cabin, ease of raising and

lowering the tower for tramming, and the ability to drill angled holes. However, operators’ opinions regarding the merits of the various models available were therefore particularly important and Boliden was able to take some of them to the Atlas Copco Drilling Solutions (ADS) premises in Garland to check out the Pit Viper rigs. Palo says the feedback was clear; the operators preferred the ergonomics of these machines, especially the joystick control. Equally, the electric version of the hydraulic drive rotary head Pit Viper (PV-351) met the Boliden managers’ requirements as to drilling capability and ease of operation. Indeed, commented Peter Palo, the team was convinced that the Pit Vipers were the most advanced rigs of their kind on the market. “I can tell you that if we looked at the market today, there’s little competition, said Johansson. “It’s the most modern machine on the market, and it’s been proved in the availability as well.” According to Johansson, the Pit Viper 351’s availability is 95%. “It’s really, really extreme,” he said. As of July 2012, the four PV-351’s have logged

between 11,000 to 15,000 drilling hours since they arrived on site in 2009.

Striving for automation Atlas Copco’s Rig Control System (RCS) technology has a number of benef its, and Boliden’s technical department took notice. Johansson said, “The probability of being able to use the autonomous functions in the future is a big reason that they wanted to buy Atlas Copco rigs.” Using automated features, such as drilling, tramming, and leveling is an attractive option for Aitik’s mine personnel, but it’s something they won’t fully implement until the future. Boliden and Atlas Copco agreed to operationally test the Pit Viper 351’s automation software back in 2009. The products were put under testing and development dating back to 2009 and the operational testing began in April 2012. The culminating test is to put a full drill plan in and to have the rig achieve predictable and repeatable results consistently. Due to the overwhelming success of the new expansion, more focus on

Blasthole Drilling in Open Pit Mining 95

Aitik eyes top three efficiency

One of the four Pit Viper 351 drill rigs at the Aitik Mine: The Atlas Copco Rig Control System (RCS) offers a wide range of features for automation, safety and communications.

the drills autonomous capabilities has been implemented by mine personnel. According to Johansson, all full-time drill operators have been trained on the autonomous functions, auto-drilling and auto-leveling, but auto-leveling seems to be favored by the drillers. “The drillers are using it more and a lot of drillers like to drill manually; the older ones,” said Palo. “The younger ones drill automatically.” But, how fast and how a fully-autonomous rig will be utilized remains in question among mine personnel. Depending on who you ask, the goal to become fully autonomous will be within the three and ten year range. When asked about how automation will improve productivity at Aitik Palo responded, “I’d really like to see it, 96

because we can drill on a shift change and dinner breaks and so on, and we can speed up production by at least 10-15%.” Johansson has set-up five shifts during the week running eight hours each, with 12-hour shifts on the weekend. That makes for a 24-hour day in which the rigs are being utilized 65% of the time. “We have downtime when we change the shifts, but it’s not something that we worry about,” said Johansson. “We do pay the operators to have the opportunity to change shifts at the rig, but today we don’t have to because of the uptime on the machines, and also the planning ahead and everything is at a level where we don’t actually have to worry.” Drilling during 80% of the shift is the goal for Aitik, and using a fully-automated rig

is how they plan to get there. Aitik will be using its Pit Viper 351’s fully autonomously at different points throughout the day in the future. Johansson states that one of the biggest benefits of running a rig autonomously is less down time for shift changes and dinner breaks. Using the rigs autonomously during shift changes and dinner breaks could increase drill time to 80% each day. Many people relate fully-autonomous functionality to staff reduction, but Johansson states that’s not the case. “They see [drill operators] autonomous drilling as a huge part as they’re participating in a project where we’ll eliminate their jobs, but we don’t have any plans to eliminate their jobs,” said Johansson. “If anything we’ll add to our staff and it’s a way to increase safety.” Not only does the RCS enable drill and blast plans to be loaded directly into the rigs’ computers, the system also provides a high level of automation, such as GPS hole navigation – a major contributor to hole depth quality – plus remote tramming and autodrilling as well as auto-leveling. The Desktop Viewer allows remote maintenance problem-solving. Moving about the PV-351 is safe and four cameras provide good visibility where there is no sight line. The 65 ft tower can be lowered in eight minutes or less, enabling much quicker relocation times than some competing rigs can achieve. The angle drilling option is relatively expensive, but Aitik calculated that having it fitted to just two of the four rigs would achieve the degree of operational flexibility required. Preparations for delivery of the PV-351 machines star ted dur ing 2008, including training at the factory in Garland, TX for Swedish Atlas Copco rig assembly and maintenance personnel and for Boliden operators. Assembly of the first machine was completed in January 2009. The local Atlas Copco team worked with Aitik engineering personnel under the guidance of Atlas Copco experts from Garland. The rigs are maintained by Aitik staff assisted by an Atlas Copco technician, with servicing after each 250 hours of operation. In June 2012 Boliden reported 95% availability. Atlas Copco has also Blasthole Drilling in Open Pit Mining

Aitik eyes top three efficiency

The drill rigs drill 200-300 holes for one blasting round and the penetration rate can vary between 0.4 m/min in the upper part and 0.1 m/min in the harder rock types. Forcit is contracted to charge each hole with about a ton of Fortis Advantage emulsion. Drilling patterns are transmitted from the mine office to the Pit Vipers using the mine’s W-LAN network.

continued to provide training for new operators, and plans to continue running culminating tests to drill an entire drill plan in a predictable, repeatable form. Atlas Copco engineers continue to create interfaces for autonomous operation, but are working with mines to define a new role of what an operator actually is.

Pit Vipers in practice The Pit Viper 351 is very heavy, with an operating weight of 185 t, and very large: 16.4 m long, 8.1 m wide and 31.4 m high with tower up. Even so, single pass drilling with the Pit Viper is a oneperson job, although the operator of a hired-in wheel loader does the power cable shifting. The hydraulic drives, cable feed system and rig control technology also make the PV-351 quite

different to operate from the rigs previously in use at Aitik. Nevertheless, according to an experienced driller, Gerd Martinsson, the PV-351 is rather easy to handle. Drill operator Hanna Wikman agrees: “It seemed pretty complicated at first but I soon got the hang of it. The controls are well placed and the screen quickly displays all the drilling data you need, engine hours, drill speed, rpm, pull-down pressure etc.” Hanna says she uses the GPS to locate her position in relation to the drill plan sent by the mine’s control center via the Wireless LAN and finds the auto de-levelling system helpful, though she prefers manual levelling. The mine works five shift groups: three 8-hour shifts daily Monday – Friday and two 12-hour shifts each day over the weekend.

Equipped with 9.9 m drill pipe and 311 mm bit (at the lower end of the machine’s 270-406 mm range), the Pit Vipers typically drill blastholes to a depth in the 17-18 m range, but in some locations down to 19.50 meters, close to the rig’s 19.8 m maximum. For standard 15 m high bench drilling the typical hole spacing is 8 x 9 meters in waste rock, 7 x 9 m in ore, and the rigs drill 200-300 holes for a blasting round designed to yield around 700,000 t rock. Penetration rates vary considerably with rock type but by October 2010 the net rate was 33 m/hour – 144 m/8-hour shift, higher than Aitik’s projected 27 m/h target. Bit life is around 1200 m, sometimes less. Forcit is contracted to charge each hole with about a ton of Kemitti 600 emulsion explosive. The company has built a matrix factory on the mine site and delivers the

Blasthole Drilling in Open Pit Mining 97

Aitik eyes top three efficiency

Aitik open pit mine, Sweden.

constituents to the blasting site. Now that management and operators have a clear idea of the Pit Viper’s capabilities and characteristics in ope-ration various tests are underway at Aitik to further boost efficiency in the future. These include using Secoroc’s new PARD (Percussion Assisted Rotary Drilling) low impact DTH hammers combined with specially designed Tricone Rotary drill bits to increase penetration rate. Aitik reports that the system increased drilling rates by an impressive 48 %. Drillers are also using the rig’s auto-tramming feature to tram to the next drilling position on the planned path so they can auto-locate each hole. The Atlas Copco Orealyser launched at Bauma 2010 has also been tested at Aitik.

Smart pre-splitting DTH While Boliden was evaluating production drilling options NCC ordered a new ROC L830 Mk II rigs to replace older machines. During 2009, when a new SmartROC D65 came to Aitik for testing, the contractor was sufficiently impressed to buy the unit for the pre-splitting contract. NCC Site Manager Stig Fredriksson says the main reason for this purchase was that the SmartROC delivers all the benefits of the Atlas Copco RCS technology. The new rig and one ROC L830 are successfully drilling both 140 mm and 165 mm pre-split holes to depths of 33-35 m, typically at a 1.5 m spacing, using Secoroc COP54 and COP64 DTH hammers and spherical button bits. The NCC team maintains the rigs and the on-site workshop houses two Secoroc 98

Pre-splitting on the Aitik benches:This SmartROC D65 is a highly productive and comfortable rig to operate in these harsh conditions where temperatures can drop to -35 degrees in winter. Together with a ROC L8 it drills 140 and 165 mm holes to depths of 33–35 m.

Grind Matic regrinding machines. Typically the bits drill about 65 m before they need a regrind and can be reground 10 times. NCC says the SmartROC has been working two shifts daily, drilling about 6,000 to 7,000 meters/month and averaging about 90% availability. The rig’s Full Drill Cycle Automation option allows the operators to prepare material on the bench while the rig finishes the hole by itself, enabling high productivity. Also much appreciated in this tough environment, where winter temperatures can drop to -35°C, both the DTH rigs have warm and comfortable cabins that make life as easy as possible. A second SmartROC D65 with some serviceability enhancements suggested by NCC arrived on site during November 2010.

Drilling with confidence Now that the expansion has been completed and mine personnel know how much the new processing plant can handle, Johansson and Palo are confident that they will be able to amp up production in the coming years, despite a low ore-to-waist ratio. Automation figures to play a vital role in the production increase, and it’s something Atlas Copco and Boliden plan to implement-fully in the future. “Potentially, it will be a must for this mine within 10 years,” said Johansson.

Acknowledgements This story first appeared in Mining & Construction 3-2010, and was updated by Justin Cocchiola who visited the Aitik mine in June 2012. Blasthole Drilling in Open Pit Mining

USA, TUCSON, ARIZONA

Asarco’s choice: both diesel and electric

Adding a diesel-powered PV-271 not only met the bench and drilling requirements that Arsarco sought from a single-pass drill rig but also offered versatile mobility. The rig moves freely about in any of Mission Complex mine’s pits.

Single pass drilling with PV-271 Efficient, profitable operations rely on the right equipment for the job at Asarco’s Mission Complex mine, one of the largest mining operations in the United States. Mine management at Mission Complex combined the cost-effective production of an electric Pit Viper 271 drill rig with the independent mobility and time-saving capability of its diesel counterpart. The result was a more efficient, more profitable operation.

Mission Complex Mine Mission Complex, located 18 miles south of Tucson and operated by the Grupo Mexico subsidiary Asarco Inc., is one of the largest copper mines in Arizona, a state that produces 65% of the nation’s raw copper. On average the total Mission Complex produces an

average of 160,000 tons of rock daily, equating to 53,000 tons of ore. Annual production in 2009 was 56.2 million tons. The mine’s ore-to-waste cut off is 25 percent copper. When they were selecting rigs to replace their aging fleet, Asarco management looked for those that could provide cost-effective, high production management of the mine’s 40-foot benches with an additional 7 feet of sub-drill. Mission’s bench patterns vary by formation, from limestone to wollastonite with many variations in the middle. The softer rock is a 30 by 35 foot pattern. They pull it in to 18 by 22 feet in the harder formations. In the past this presented them with problems with pipe, because the rock is so abrasive. To meet the demanding conditions of a mine of this size and of rock this hard on tools, mine management combined the features of diesel and electric rigs. They focused on two Atlas Copco Pit Viper blasthole drill models, ultimately choosing the single-pass capability of the PV-271 over the 351s.

They are now running two PV-271s. One is a diesel model, just under three years old. The second, the electric model, entered service in December 2009. They purchased the diesel model to extend the drill reach from the existing power capacity and to add versatility to their drill fleet. At the time, they were operating vintage electric-powered rigs and one fairly new diesel-powered DM-M2 in three pits. Adding a diesel-powered PV-271 met the bench and drilling requirements in a single-pass drill rig that also offered versatility and could move in any of the pits. To make the 47-foot holes they run the PV-271 with two 25-foot and one 8-foot section of Atlas Copco 8 ⅝-inch Teamalloy pipe. Below that they use a 41-inch bit sub adapter above a Secoroc air-bearing 10 ⅝-inch tricone bit.

Comparable performance Aside from one having a power cable, “The drills operate identically,” said Juan Salido, a Mission mine driller.

Blasthole Drilling in Open Pit Mining 99

ASARCO’S MISSION COMPLEX MINE

manpower required to build the infrastructure and to move the cable during each relocation must be included in the comparison.

Outfitting the rigs

The diesel powered PV-271 moves with ease back and forth on the bench increasing productivity by reducing setup time.

The electric drill came with a larger compressor, 2,600 CFM, whereas the diesel Pit Viper has a 1,900 CFM compressor. In regard to drilling productivity, both average 8,000 to 10,000 meters per month. Mine manager Hal Galbraith said the diesel PV-271 worked great for his mine. “I wouldn’t say we ran the tracks off the rig, because we did haul it on our lowboy too, but it went everywhere in the mine.” Since then, the mine has focused operations to just two of the pits, but the diesel Pit Viper still moves wherever needed within the mine.

Time on task favors diesel Drill and blast manager Larry Maddox noted that the diesel rig offers a significant advantage, working well at moving into tight spots on the bench to allow drilling to continue before power is moved into the working area for the shovels. “Moving an electric drill just takes more time compared to a diesel rig: having the cable crew available, cutting the power, moving the cable, planning the cable drops. You just can’t put a value on the mobility you get from a diesel drill.” Salido added that “it may only take 20 minutes to move the cable but 40 minutes or more for the crew to get there.” Anything that slows a cable moving crew stops operations. For example, if the cable needed to be moved for 100

an afternoon blast and the crew got a flat tire on the cable truck, everything would be held up until the tire could be changed. The diesel model obviously maximizes time spent drilling. Softer rock at the mine may take only 20 to 30 minutes to drill each 47-foot hole. Other formations that contain more garnettectite and wollastonite, however, may require as much as two hours for the same hole requirements. Maddox said, “I think if you had plenty of time, electric would be better because of the cost to operate and maintain, but mobility more than makes up for it with the diesel drill.”

Comparing operating costs One exception to this preference for diesel is in operating cost. The electric drill currently operates at 61 percent of the energy costs of the diesel drill. There is a point when this advantage outshines the time-saving, independent mobility of the diesel rig. For instance, when diesel fuel edged up to $4 a gallon, the electrical rig was more attractive. Galbraith listed some of the additional, indirect costs to factor in with use of an electric drill before making a decision. Each electric rig requires four 4,000-foot cables at $100,000 each. A 138- 4160 substation to power the drill costs $250,000. Additional

Efficient drilling operations at Mission are the result of strategically matching pipe and bits to these PV-271s. Teamalloy pipe has a much higher cost per piece price than other pipe but its durability and longevity mean cost per foot is less in the long run. A 25-foot section of Teamalloy pipe lasts 6 weeks at Mission. Initial outside dimension of the pipe is 8.65 inches. They will run it down to 8 or 7.9 before replacing it. The pipe shows its wear at the lower end of the joint, in what operators refer to as a “penciling” effect. They rotate these sections, since sections closer to the bit wear faster. This distributes wear evenly among the sections to increase longevity overall. As for bits, the air-bearing works the best in this formation with an average life for a bit at 7,500 to 8,000 feet. Each drill will go through about two bits a week, depending on the ground.

Bottom line For Larry Maddox the choice is simple, “I want to keep them both.” He says each has characteristics that make the operation more efficient and productive. For the company, that means greater profitability. “Electric may be cheaper, but the mobility with diesel is better.” Galbraith said the decision to buy the right equipment for the drill and blast process is justified by the bottom line: “For every dollar more you spend up front on drilling, you’ll make $10 on the back end.”

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 1 2011. Story and photos by Scott Ellenbecker, Ellenbecker Communication, who visited the mine in June 2010.

Blasthole Drilling in Open Pit Mining

CANADA, PRINCETON, BRITISH COLUMBIA

Reopening of Copper Mountain Data-based confidence in projections

The diesel PV-271’s independent utility enabled it to set up quickly in any part of the Superpit, especially beneficial during pit push backs.

High-tech pays off In spite of extreme cold weather arriving earlier than expected, Copper Mountain Mining Corporation’s careful planning, perseverance and high tech investment in reopening a 15-year dormant copper mine remains on track to achieve full production by June 2011. This was achieved by combining the benefits of both diesel and electric-powered Pit Vipers in their blasthole fleet. Their success has inspired interest in other regional mines abandoned decades ago when mineral prices fell. Intelligent fleet choices are proving that revisiting these mines can be a promising venture.

Promising outlook It’s a full six months before startup, yet an historic mine being reopened by the

Copper Mountain Mining Corporation is already rewarding the Princeton, British Columbia, region with new jobs and a promising outlook for an economic windfall from the billions of dollars of copper, silver and gold the mine will generate. It comes none too soon for this area of British Columbia, whose forest industry has suffered from both pine beetle devastation and a downturn in the forest industry overall. During its previous life, the openpit porphyry mine had already yielded 770,000 tonnes of copper, 258 million grams of silver, and 20.7 million grams of gold from 23 years of continuous production before it closed in 1996, when copper prices were low. Exploration in 2006 by its new owner, however, promised that the mountain would reward the company with another 17 years’ worth of production from its untapped mineral deposits.

Combined evidence from past drilling and modern exploration convinced stakeholders that there are still at least 680,000 tonnes of copper left, with precious metal credits of more than 12.8 million grams of gold and 127.6 million grams of silver. Earlier this year, Copper Mountain Corporation President and CEO, James O’Rourke, said the company anticipates full production to reach 32,000 tonnes per day, amounting to over 45,000 tonnes of copper a year and reaping significant amounts of gold and silver as by-products. With operational and financing costs totaling about $1.30 (USD) per pound, the copper will sell at about $2.80, which O’Rourke notes is a significant margin. The overwhelming evidence that there are significant resource deposits yet to mine come from nearly 5,000 historical drill holes combined with more than 400 of the company’s own. Continued exploration of the deepseated porphyry in the fall of 2010 further confirmed extrapolated predictions. And the life of mine strip ratio is estimated to be just 2:1.

High profitability, low risk Although reopening a mine of this size is a formidable task, the project did come with some built-in benefits, such as a ready, skilled workforce from previous mining operations in the area, as well as a pre-existing infrastructure at this site. Only 15 miles from the town of Princeton, a paved highway runs past the mine, and the site has ample water resources with an ideal location for processing the extracted ore. Copper Mountain partnered with Mitsubishi Materials early on, who provided ideal security for the venture both in financial backing and by ensuring the mine a reliable buyer for the ore. The conscious effort to reduce operational risk has been evident in every

Blasthole Drilling in Open Pit Mining 101

Reopening of Copper Mountain

By December, the rig had already logged more than 1,200 hours.

compressor packages, are well-matched to 270 mm (10 ⅝") Epsilon rotary bits, which will allow quick clearing of the holes. Pratico said the rigs are working well driving 7.62 meter (25 ft) drill pipe while smoothly operating on the mine’s 15-meter (49 ft) benches to stay ahead of scheduling goals. The electric model does give them the benefit of lower operating costs. Other than that, the diesel and electric perform comparably.

The diesel rig’s components arrived on site in September.

component of the enterprise, including choice of equipment. For instance, to move the 22.7 million tonnes of material by May 2011 in preparation for full startup in June, and then to move the additional 54.9 million tonnes anticipated during the first production year, all blasthole drilling has been awarded in a three-year agreement to Altas Copco and its Pit Viper series, as well as all drilling rig parts, ancillary equipment and tools. Gary Wright, the Atlas Copco sales representative for southwestern Canada, said, “It’s good for startups because it creates a partnership with the manufacturer and the mine. It includes everything from service to the steel and bits and allows everyone to work together.” The first rig, a diesel-powered PV-271, which had been in operation since September, was joined by its electric counterpart in November. A second electric model, a PV-351, completed the trio of Pit Vipers at the site in January 2011. Alastair Tiver, Copper Mountain’s Chief Engineer, said a mix of electric and diesel is working well. “Use of electric allows us to lower operating costs,” he said. “The pit will be developed with a series of push backs, so having a diesel rig affords us some additional mobility to move a rig from one mining area to another, 102

should additional drilling capacity be required.”

Strategy for reaching the metals Peter Holbek, Vice President of Exploration and leader of the mine’s exploration teams, explained the three-pronged approach the company is undertaking to realize the company’s production goals. They have incorporated and expanded all three pits of the mine under one all-encompassing “Super Pit.” First the company will drill in areas of known mineralization from the previous operation. Second, they will drill in outer target areas that, although they were drilled previously, were not fully explored. And third, they will go after deeper targets, confident in the corroborative data from the new and historical information. The company purchased the original, diesel-powered PV-271 for its ability to move quickly into other areas without the need to relocate power. The decision to purchase electric-powered Pit Vipers was based on economy. Although they would have purchased a third PV-271, Mine Manager Art Pratico said the PV-351E was immediately available. The current PV-271s, with their ample 2,600 CFM (73.6 m 3/min) air

One-source logistics Copper Mountain Mining teamed with Atlas Copco for the complete supply of all required rock drilling tools. This provides not only the convenience of a one-source supply but also means Atlas Copco is in frequent contact with the company, maintaining instant access to customer support. Service is instantaneous. So how has the PV-271 been performing overall? Pratico said he is pleased with the machine. The diesel rig had already logged 1,200 hours of operation by December. It not only performs well, but it is also being used as a trainer. The PV-271’s high-tech upgrades give operators rich options without alienating those who are new to the series. It “operates just like any other drill rig,” Pratico said, meaning it doesn’t require a steep learning curve to train an operator’s skills to proficiency on a Pit Viper. That drillers can acquire proficiency with the rigs quickly is just one more contribution to helping the mine keep on track for the June 2011 deadline.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction USA No. 1, 2011 Story by Joseph Bradfield. Pictures by Gary Wright. Blasthole Drilling in Open Pit Mining



CHILE, Andes Mountains, antofagasta

Radomiro Tomic prioritizes service Chilean mine’s successful strategy– combining expertise of drillers, technicians. Proper care of machinery and tooling directly contribute to the success of Chilean mines, which lead the way in mining efficiency and safety in Latin America. A prime example is Codelco’s Radomiro Tomic Mine in northern Chile, located 3,000 meters above sea level in the Atacama Desert. The mine entered into a 10-year service agreement with Atlas Copco that not only facilitates high production but frees up the company to focus solely on mining.

Planning for long term operation In 1997 the National Copper Corporation of Chile, or Codelco, named the Radomiro Tomic mine after a political reformer who was a primary force behind the nationalization of the copper mining industry in Chile. Known locally as “RT,” Radomiro Tomic is located 1,670 kilometers from Santiago, in the Andes Mountains of northern Chile. Although the oxide copper porphyry there was discovered in 1952, Coldeco’s operations did not begin until 1995, when improvements in technology made mining the resource profitably feasible. The Radimiro Tomic deposit lies beneath approximately 100 meters of alluvial material and extends over 5 by 1.5 kilometers by 200 meters. Operations at RT show a strategy for long-term success and the mine is expected to become the model for other mines. RT features a service solution that frees its miners to focus on mining and ensures support of expert technicians in a highly efficient maintenance program.

The Pit Viper 351 at work in the Radomiro Tomic Mine at 3 000 m in the Atacama Desert in northern Chile, known as the dryest in the world. Here, Atlas Copco takes care of all service and maintenance of the drill rigs.

To fulfill the 10-year agreement for service and maintenance of RT’s drill rig fleet, Atlas Copco has established an onsite service team of about 50 people who will take care of 11 drill rigs including the Pit Viper 351, ROC L8, DMH and DML models. Three additional Pit Viper 351 rigs are due to be delivered at the end of 2011. By that time the service team will have increased to more than 60.

Two programs in force Two different service programs are in operation at the mine—a labor-plusparts program (LPP), which supports older drill rigs, and a maintenance and parts replacement contract (MARC) for all new rigs. Since the history of each part or activity of the used equipment is uncertain, it is not efficient to apply a fully comprehensive service program. This makes an LPP more suitable for this part of their fleet. Parts are provided by the mine in accordance with their

consumption and the labor is provided by Atlas Copco at a predetermined rate. The MARC program, on the other hand, is a complete maintenance and repair service program that applies to all new rigs as they arrive. A clear history can be tracked from the first hole drilled. The contract consists of all maintenance and repair routines required to secure high availability and reliability. This includes preventive, planned and corrective maintenance as well as condition monitoring. All necessary parts, repairs and labor are provided by Atlas Copco at a guaranteed rate. A predetermined performance level defined by Key Performance Indicators (KPI) has also been established, using a maintenance-balanced score card as a measurement tool. For example, it is expected that the Pit Viper rigs will be available 90 percent of the time. The mean time between failures (MTBF) is 44 hours and the mean time to repair (MTTR) is 3.5 hours. This translates to an average of 44 hours of straight

Blasthole Drilling in Open Pit Mining 103

Radomiro Tomic prioritizes service

Controlling dust is an important function at all mines. Here water is being pumped into the ROC L8 for collaring the hole, which controls surface dust.

Operator Fernando Acuña finds automation relaxing as he waits for completion of the hole on his Pit Viper 351.

operation before the rig is shut down for no more than 3.5 hours before it’s up and running again. The DMH, an older, used rig, has an availability rate of 78 percent while its MTBF is 29 and its MTTR is 3.5. Each drill rig is covered by the contract independently and record keeping is meticulous. The system requires considerable management expertise as well as technical skill, and in this region of Latin America Atlas Copco is well equipped to provide both. The service team is part of the its overall

Total focus on drilling

Atlas Copco Service Technician Juan Bustamante takes a break from working on the electrical Pit Viper for a photo.

104

customer support effort in Chile, which has also resulted in the creation of a Competence Development Center in Santiago. The onsite Atlas Copco team is divided into three categories: planning, execution and logistics. The planning team, the smallest group, works on short term and long term planning needs for parts and fluids. The execution team, the largest group, is dedicated to maintenance and repair tasks. The logistics group is responsible for administration, warehousing and purchasing. “The purchase of capital equipment is a small part of the overall demands at RT, whereas having the qualified people to keep the equipment operational is a large part of the mine’s success,” said Eduardo Fajardo, Atlas Copco’s administrator on the site. “As equipment becomes more technical and qualified labor becomes more difficult to hire, mines are looking to companies that can provide the total package.” The Atlas Copco Competence Development Center was designed to put more than 100 skilled technicians at the disposal of its clients. These open pit and underground equipment specialists provide training in maintenance and skills required in such areas as RCS, electronics and hydraulics. The Center’s mission is to develop every entrant into a master technician.

Fernando Acuña, an operator at RT who has ten years of drilling experience and many more as a loader operator and truck driver, said learning to handle the computerized Pit Viper was not difficult. He pointed to a display screen showing an rpm of 78 and an indicator showing a penetration rate of 0.5 m per minute. The rig keeps its operator informed of everything that is happening during the drilling process. Normally the rig operates at 1 meter per minute and takes about 20 minutes to drill an 18-meter hole with an 11-by11 meter burden and spacing pattern. The rig that day was running with a weight-on-bit of 27 tonnes. It is capable of 54 tonnes weight-on-bit. With an an nual production of 300,000 tonnes of cathode copper, the Radomiro Tomic mine continues its steady growth by combining the experience of its drill rig operators with the service and maintenance experience of Atlas Copco, leaving each to their area of greatest expertise.

Acknowledgement Article and photos by Scott Ellenbecker. Originally published in Atlas Copco Mining & Construction magazine, No. 2/2011.

Blasthole Drilling in Open Pit Mining



CHILE, Atacama Desert, antofagasta

Automation at Escondida Company triples mine life with high tech drill rigs A l t h o ug h E s c on d i d a M i n e r a literally translates as “hidden mining,” it’s no secret that it can maintain its position as the largest copper producer in the world by stepping up its investments in automation. The largest copper mine in the world is updating its fleet with units that feature Atlas Copco’s rig control system (RCS).

Growth strategy

The Pit Viper 351 working in the Escondida pit..

Escondida’s growth plan emphasizes four basic principles: be safe, put people first, do things right the first time and think to the future. These are the principles that guide the management in developing the operation and planning equipment purchases. For Escondida, doing things safe, right and with the future in mind means their drilling equipment must be mobile and offer autonomous capabilities both in the cab and for mine planning. “Growth to us means autonomous high production drilling,” said Juan Carlos Fuentealba, who is the mine’s drill and blast manager. The mine has strategically moved its drilling operation toward greater automation with the recent introduction of units built upon Atlas Copco’s RCS platform. The fleet so far consists of 120 haul trucks, 18 shovels and 18 drill rigs. Anticipating its future drilling needs, the mine will phase out its aging fleet of Bucyrus 49R electric rigs for a mixed fleet of Atlas Copco diesel rigs. The main production model will be the Pit Viper 351, of which two are currently in operation. Three DM45s, a DM-M2 and a PV-271 are also on site. Two additional PV-351 rigs are scheduled for delivery in the third quarter 2011.

Blasthole Drilling in Open Pit Mining 105

Automation at Escondida

Escondida operates two open pit copper mines in the Atacama Desert, 170 kilometers southeast of Antofagasta in northern Chile. Escondida produces mainly copper concentrates, which are piped as a slurry down to the port of Coloso where they are dewatered before shipping, and a smaller proportion of cathode copper from the leaching of both oxide and low grade sulfide ore. It also produces gold and silver.

The smaller rigs drill 200 mm (7 ⅞-inch) holes while the PV-351 rigs drill either 276 or 318 mm (10 ⅞- or 12 ½-inch) holes, depending on the material. The benches are 15 meters high with additional 1.5 to 2 meters of subdrilling.

Focus on mobility The mine produces about 300,000 meters per month from its two pits, Escondida and Escondida Norte, with the smaller drill rigs primarily drilling buffer holes. Two rows of small diameter holes are used between the production holes and the final pit slope to optimize rock fragmentation. At Escondida, Atlas Copco ROC L8 rigs drilling 165 mm (6 ½-inch) holes are used for presplitting work. The mobility of the PV-351 is a key contributor as it moves from bench to bench and pit to pit. The Pit Viper can also be moved with the tower up, 106

or with a “live tower” on the bench, something that could not be done with the old fleet. Production in the pits has also increased, mainly due to the new rig’s availability, and to the penetration rate of the Pit Viper, which is also better compared to the fleet’s older units that the Atlas Copco rigs are replacing.

Other benefits of automation As the mine moves forward, the management is also looking forward to using the new training simulator that the Atlas Copco Customer Center is bringing to the country. Hugo Reales Trigo, Drill and Blast Superintendent and General Operations Manager, noted one advantage of using a simulator is that training does not take a drill out of production. It is also safer, as it reduces the number of people working on the bench. He added that automation

increases safety even while eliminating or reducing the need for many timeconsuming safety procedures. A big advantage of the Pit Viper for Escondida is the rig’s GPS navigation capability. This allows the drill pattern to be located via computer and downloaded to the rig’s onboard computer. All operational data is also stored to make the rig’s performance and service record easy to monitor. Such automated features as these in Escondida’s fleet will ensure that this operation remains the most productive copper mine in the world, with the safest operation possible.

Acknowledgement Article and photos by Scott Ellenbecker. Original article published in Atlas Copco Mining & Construction magazine, No. 2/2011.

Blasthole Drilling in Open Pit Mining



CHILE, sierra gorda, Antofagasta

Ambitious target at Esperanza

Esperanza has proven and probable copper reserves of 583 million tonnes with an expected average annual production of 714,000 tonnes of concentrates containing 190,000 tonnes of payable copper and 230,000 ounces of payable gold over the first 10 years.

Rotary and DTH drilling Esperanza mine was from day one designed to use sea water as a conservation measure and is aspiring to become Chile’s next big mining operation by using even more of the latest in technology and equipment. Utilizing Atlas Copco drill rigs, the mine is using PV-351 rotary rigs for production drilling, DM–M3 rotary rigs for buffer holes and DTH rigs such as the Atlas Copco ROC L8 for pre-splitting the benches.

Large scale mining The Esperanza mine in the Antofagasta region is a young mine with big ambitions. Opened in 2008, the first blast took place in March. The initial blasting, ending in July 2010, included the largest removal of overburden in the mining industry–more than 150 million tonnes.

The mine plan considered that the pit will reach dimensions of 2,100 meters long, 1,750 meters wide and 770 meters deep. The main metal is copper, but the ore also yields gold and molybdenum. The Esperanza project is one of the few high-profile development copper projects remaining globally, under joint ownership of Antofagasta PLC and Marubeni Corporation. The groups mining division is one of the largest international copper producing companies in the industry. Its activities are mainly concentrated in Chile, where it now owns and operates four copper mines: Los Pelambres, Esperanza (in start up), El Tesoro and Michilla, with a total production of 521,100 tonnes in 2010. As a new mine, Esperanza has had the opportunity to adopt the most modern mining practices right from the beginning. That willingness to embrace innovation has included the latest updates to its Atlas Copco Pit Viper drill rigs and a conservative use of water.

Antofagasta focus for exploration in Chile remains in the Sierra Gorda District. The group owns or controls a number of properties there: Esperanza (and the concentrator plant) and the El Tesoro operation, which means Antofagasta is well placed to develop this area as a wider mining district. The Telégrafo deposit could be used to extend the life of Esperanza, or increase its size of operation.

Water is a scarce commodity in northern Chile, home of the Atacama Desert. In one of the driest climates in the world, Esperanza is a pioneer in the use of seawater without desalination in large-scale mining processes. To get the water from 145 kilometers away, the mine pumps water at 630 liters per second to an altitude of 2,300 meters (7,500 feet). To avoid excessive electricity use, Esperanza does not desalinate the water before using it. Atlas Copco is supplying blasthole rigs in a variety of sizes for this mine to work at peak efficiency. The practice is to drill 16-meter holes with a 1.5 to 2 meters subdrill. The drilling pattern varies with the type of rock being drilled. In sulfides the pattern is 6.5 by 7.5 meters, and in oxides the pattern is 7.5 by 8.5 meters. Waste is drilled at 9 by 11 meters. For safer pit slopes, an Atlas Copco ROC L8 drills a line of 165 millimeter (6 ½-inch) holes along the wall for presplitting. The blast creates a clean crack between 2-meter spaced holes. The line

Blasthole Drilling in Open Pit Mining 107

Ambitious target at Esperanza

One of the four Pit Viper 351 rigs.

ROC L8 DM-M3

PV-351

Pre-split Holes 165 mm (6 ½ in.) diameter holes

Buffer Holes 269 mm (10 5⁄8 in.) diameter holes

rm Be

2m

Production Blast Holes 269 mm (10 5⁄8 in.) diameter holes for ore and 311 mm (12 ¼ in.) diameter holes for waste

4.5 m

2.8

m

4.5 m

sulfi 6.5

6.5

m

des

4.5

m

m

7.5 m 7.5 m

In oxides the drill pattern is 7.5 by 8.5 meters. Waste is drilled at 9 by 11 meters.

16 m

Chosen for its advanced technology the majority of the production drilling is done with four Pit Viper 351 rigs, drilling 16-meter holes with a 1.5 to 2 m subdrill. Drilling of the buffer holes are done by two DM-M3 rigs and the holes for pre-splitting with a ROC L8.

is drilled 2.8 meters from the closest blast pattern holes. Almost all of the benches are presplit for safety reasons but especially when they are near a haul road. A buffer zone is drilled next in the pattern, preventing the impact of the main blast from transmitting its full energy into the wall. It consists of a double row of 1,269 mm (10 5⁄8 inch) holes drilled with two Atlas Copco DM-M3 drills. The buffer zone is shot after the main blast with only a slight delay. The DM-M3 rigs are also used for production drilling when necessary.

Progressive mine and drill rigs The majority of the production drilling is done with four Atlas Copco Pit Viper 351 rigs drilling 269 mm (10 5⁄8 inch) holes in ore and 311 mm (12-inch) 108

holes in waste. The PV-351 is capable of drilling blastholes up to 406 mm (16-inch) diameter to a maximum depth of 135 feet. The PV-351 was chosen by Esperanza for its weight in relation to hole size, pattern size and bench height, and also because of its advanced technology. The mine converted to the latest version equipped with the Pit Viper’s Rig Control System (RCS). Operator Herman Gospochetic said, “Positioning is much faster with RCS, and I feel I get more done,” he said. “The remote control upgrade on the system is also more user-friendly.” Other Pit Viper options include fire suppression systems and computercontrolled central lubrication. Options specific to the PV-351 include a cold weather package for operation in ambient temperatures down to -40° C, a four-camera LCD vision system and

The operator gets more done with this rig. It is easy to operate and positioning is faster with RCS. The PV-351 was chosen by Esperanza for its weight in relation to drilling capacity and also because of its advanced technology.

attention horn, and a wireless remote propel control. Remote control tramming with the operator off the rig is mandatory in certain situations under some regulatory authorities. Additional options are a Hiab crane for loading and unloading bits and accessories, hydraulic retractable staircase, tower ladder and much more. Esperanza is at the beginning of its life. With modern methods and equipment, it is aiming for a long and prosperous future through its estimated life to 2027, possibly longer.

Acknowledgements Article and photos by Scott Ellenbecker. Originally published in Atlas Copco Mining & Construction International magazine, No. 2/2011.

Blasthole Drilling in Open Pit Mining

Chile, iquique, Tarapacá Region

Raising to the altitude challenge Diesel rigs drill fast The newest drilling machines at the Collahuasi open pit mine in Chile are two snakes from Texas impressing with their power, versatility and superior technology in extreme conditions - The Atlas Copco Pit Viper rigs claim their territory.

In the northernmost part of Chile, high in the Andean plateau of the Tarapacá Region, sits the giant Collahuasi mine, one of the world’s largest copper resources. Here, mining operations take place at altitudes of between 4,000 and 4,800 metres above sea level, making this one of the most challenging work environments for any mining equipment. The mine is operated by a joint venture company - Compañía Minera Doña Inés de Collahuasi – owned by Anglo American and Xstrata (44% each) and a group of Japanese companies headed by Mitsui (12%). Collahuasi extracts and processes sulphide ores to produce copper and molybdenum concentrates and oxide ores to produce copper cathodes. Of these, copper concentrate is the main product, accounting for over 90% of the mine’s output of contained copper. Commissioned at a cost of US$1.76 billion (which turned it into the mine with the largest single investment in Chilean history), commercial operations at Collahuasi started in April 1999. After a US$584 million expansion in 2004, the mine now has an installed copper production capacity of 500,000 tonnes per year. Even this figure was comfortably exceeded in 2009 when Collahuasi produced a record 535,853 tonnes of contained copper. In mid 2011, a prefeasibility study was started to see whether a second expansion would be economically viable. The study contemplates two options: a fourth mill line, which would take production to 800,000 tonnes per year or a fourth and fifth lines together, which would take production to over

The PV-351 and the PV-271 are the only diesel units in a fleet of 11 production drill rigs at the Collahuasi mine. Both rotary machines are drilling vertically an to a maximum depth of 18 meter.

Blasthole Drilling in Open Pit Mining 109

Raising to the Altitude Challenge

Above: Carlos Correa Echeverria. Top right: operator of the PV 351. Bottom right: The PV-351 and PV-271 at Collahuasi copper mine.

1 million tonnes per year. According to an official press release by Anglo American, the study is focused on evaluating both options and whichever option is taken; the project would be commissioned in 2017. The expansion project, which will be for the production of copper concentrates, is in line with the company’s vision of being amongst the leading copper producers by 2020. Collahuasi currently accounts for about 9.3% of Chile’s total copper output, which positions it as one of the country’s main producers and a leading international player. The mine has an expected life of over 30 years and the company has production plans in place up until 2040. According to the company official figures, mineral resources total 7.1 billion tonnes at an average grade of 0.82% copper. This includes ore reserves of 3.1 billion tonnes, 2 billion tonnes of which is accessible. There are approximately 5,500 people currently working at Collahuasi, including contractors. The mine works 110

non-stop 365 days a year with a pattern of two 12-hour shifts a day; from 8am till 8pm and 8pm till 8am. “We would only stop if we are badly affected in winter,” says Carlos Correa Echeverría, Superintendent Drilling & Blasting at Collahuasi, referring to the harsh weather conditions in the Andean high plateau. “We need all our equipment to sustain consistent and reliable performance while operating at maximum production capacity,” says Correa. This is easier said than done when that equipment has to operate at very high altitude, at very low temperatures and during occasional electric storms. This is the environment in which the two new Atlas Copco Pit Viper blast hole drilling rigs, a PV-351 and a PV-271, have had to prove their worth.

Mining & processing Located in an area of historical copper mining, Collahuasi consists of three major copper deposits: Ujina, Rosario

and Capella. Lying at an altitude of 4,100 metres, Ujina contains secondary sulphides and oxides. This deposit (plus a smaller oxide deposit called Huinquintipa) was the first to be mined; representing the first stage of Collahuasi. Currently a total of 50,000 tonnes per day of rock is extracted from Ujina and a total of 45,000 tonnes per day is extracted from Capella, which contains oxide copper ore. Still higher, at an altitude of 4,600 metres is Rosario, a deposit that contains secondary enriched sulphides and oxides with a relatively high copper grade of 1.1%. Stripping at Rosario began in 2002 and this has now become the principal source of ore at Collahuasi; currently over 600,000 tonnes per day of rock are mined. Rosario Sur 1, a new area where work has only just started, is contributing another 10,000 tonnes per day for a grand total of 705,000 tonnes per day of extracted rock. Most of the mining equipment is deployed at Rosario, including the Blasthole Drilling in Open Pit Mining

Raising to the Altitude Challenge

drilling fleet and some large capacity loading and hauling units. Collahuasi boasts over 40 ultra class haul trucks from different suppliers, with a rated capacity of between 240 and 370 tonnes. These are loaded by a fleet of electric rope shovels, supplemented by a few hydraulic shovels. After drilling and blasting, the Runof-Mine ore is hauled to the processing area. Because of the presence of both, sulphide and oxide ores, Collahuasi employs two processing methods. Sulphide ore is crushed, ground and treated by flotation and oxide to yield a concentrate whereas oxide and mixed ores are treated by heap-leaching, solvent extraction and electro-winning (SX-EW). The sulphide ore enters a primary gyratory crusher prior to transport to two parallel grinding circuits, each consisting of a SAG mill and a ball mill. Secondary closed circuit grinding includes cyclone classifiers, from which the overflow feeds the flotation circuit. Flotation concentrate is thickened to 50% solids for slurry transport in a 200 km-long pipeline to the port of Punta Patache, 60 km south of Iquique, where it is thickened and filtered before shipment to smelters worldwide. The oxide ore is reduced to -10mm by three-stage crushing. The fine ore is agglomerated before being conveyed to the leach pads where it is leached using sulphuric acid. Copper is recovered from the pregnant leach solution in the electro - winning plant, where the copper is stripped using organic solutions; the stripped liquor is then returned to the leach pads for re-use. The strip solution is cleaned using dilute acid and flotation and is filtered prior to the electro-winning phase, where the copper is plated onto cathodes. These are stripped by the Kidd process on a seven-day cycle and the cathode copper is then transported by road to Iquique for export. Hard Rock Geologically speaking, Collahuasi is a por phyr y copper deposit. Approxi-mately 50-60% of the world’s copper and 95% of molybdenum comes from porphyry deposits and indeed, the greatest concentration of large copper porphyrys is in Chile. The major ore minerals at Collahuasi

The Collahuasi mine, one of the world’s largest copper resources, is located high in the Andean plateau and operations take place at altitudes of between 4,000 and 4,800 metres above sea level.

are chalcocite, chalcopyrite and bornite. Oxide mineralisation occurs mainly as chrysocolla with minor brochantite, native copper, and copperiron-manganese oxides and hydroxides. “The rock here has special characteristics; it’s altered with quartz so it’s harder,” says Correa, explaining that the rock at Collahuasi has an average strength of 100 megaPascal (MPa), with some sectors reaching even 250 MPa. For comparison, the rock at other local mines has a typical strength of 60 MPa. Nevertheless, there are some geological faults. “Some areas can be unstable with the risk of wall collapse,” says Correa, explaining that this, however, does not happen abruptly. A radar system is used to scan the walls so the risk of collapse can be controlled. The stripping ratio at Collahuasi varies depending on pushback development but the average is 4:1 (waste: ore). Bench heights are a standard 15 metres with 1 and 2 metres of subdrilling depending on the drilling pattern. There are no double benches due to the

low quality of the rock mass. Blasting at Collahuasi is carried out once a day and four different drilling patterns are used depending on the area. “Some areas contain ground water so we have to take this into consideration. Depending on the presence or not of water, we use heavy ANFO or ANFO & emulsion,” says Correa, adding that they employ a remote electronic initiation system.

Drilling & Vipers On the drilling front Collahuasi currently employs a fleet of 19 rigs of which 11 are used specifically for blasthole production drilling including the two Pit Viper units. They are the only diesel drilling rigs working in production as the other nine are electric rigs. There are three other rotary diesel machines from another supplier, which are being used to drill 7 ⅞” buffer holes. These are the holes positioned on the last two or three rows close to the walls. “These holes must be drilled with a smaller diameter than production

Blasthole Drilling in Open Pit Mining 111

Raising to the Altitude Challenge

September), when temperatures can reach -40°C. “That means that the rigs also have to be fitted with a heater and an on-board generator,” continues Espindola, explaining that elements such as the water pump, fuel, battery and oil can all be affected by the very low temperatures.

Pit Viper 351

Once they arrived in Collahuasi, the Pit Vipers went straight to the Rosario deposit to work in production drilling. Some areas in this deposit are narrow and have water but this is not a problem for the versatile diesel rigs.

holes as they require a smaller explosive charge in order to minimize damage to the wall or the slopes,” explains Correa, adding that normally, these holes are drilled to the height of the benches, without subdrill. For pre-splitting, Collahuasi employs four smaller diesel rigs, which are drilling 4 ½” diameter holes to a depth of 16 metres and at an angle of 70°. The Pit Vipers were delivered in April and May 2011 and both went straight to Rosario to work on production drilling. The PV-271 unit is drilling 10 ⅝” diameter blast holes and the PV-351 is drilling 12 ¼” diameter blast holes. Both rotary machines are drilling vertically and to a maximum depth of 18 metres. According to Correa, the diesel machines have proved ideal for work at this deposit: “We’ve hit a phase in the Rosario deposit where the working area is narrow and there is water,” he explains. “It is very convenient for us not to have to deal with the cables of the electric machines in that area.” 112

Also important is the machines’ versatility: “Moving electrical cables about results in lost time, and that’s why we decided to go for a diesel version. We like the versatility of the Pit Vipers as we can move them around quickly and without problems.” However, the high altitude and consequent reduction in oxygen, means a loss of power in any diesel machine. “This makes the rigs less efficient and so we had to compensate for this by fitting them with higher-powered engines and compressors,” says Paulyn Espindola, Product Manager, Atlas Copco Drilling Solutions (ADS), explaining that the Pit Vipers at Collahuasi are f itted with a compressor giving a low pressure rotary of 3,800 cfm @ 110psi instead of 3,000, which would have normally been enough. Equally, the rigs feature a more powerful engine, in this case one delivering 1,650hp @ 1,800rpm. T he high altit ude also means extreme low temperatures, especially in the South American winter (July to

Although both rigs have had a good general performance, it is the larger unit that has stolen the show: “The PV-351 is drilling about 10% faster than the electric rigs, roughly 58 metres per hour, whereas the electric machines are drilling an average of 50 metres per hour,” informs Correa. This was confirmed on site by Eduardo Macheo, the operator of the PV-351: “I like this machine; it’s fast. I’ve been able to drill 780 metres with it in one shift of 12 hours (that’s including a one hour break). But I can do better; my personal record is 800 metres in one shift and I’m sure I can reach that with the 351!” he laughs confidently. Macheo felt familiar with the rig from the start as he used to work on another Pit Viper unit before, albeit the smaller 271 and not one equipped with the Rig Control System (RCS). “Before I came here I worked at another large copper mine and there I had the opportunity to operate the 271 machine. I had a console for operation though, not joy sticks, so the whole computerised system and the joy sticks were a new experience for me,” he says. The RCS computerised system comes as standard on all PV-351 rigs and provides a high level of automation, including autodrilling, GPS hole navigation, rig remote access with communication, remote tramming, measure while drilling and tele-remote operation amongst other advanced features. All the rig functions are controlled through a touch screen, two joy sticks and push buttons on the operator’s seat, so when the seat swivels, the joysticks and screen swivel in conjunction. When the two Pit Vipers arrived, Atlas Copco provided two experienced instructors, to train approximately 20 people at Collahuasi. The technical training was completed only in January this year. Blasthole Drilling in Open Pit Mining

Raising to the Altitude Challenge

Macheo admits it has been a learning curve but an easy and enjoyable one: “Oh, it wasn’t a problem at all to learn to operate it. It did help that I had already worked on the 271 but the controls are very straightforward,” he says, praising the cabin and its great visibility. “It’s easy for me to work in here, it feels safe and I’m happy.” Featuring a powerful hydraulic pulldown, the PV-351 has also impressed Collahuasi with its great capacity: “Before, there wasn’t a diesel machine with this capacity and for us this results in greater availability in time,” says Correa.

Atlas Copco inside Collahuasi Before the Pit Viper units arrived, Atlas Copco did not have a significant presence in Collahuasi in terms of large equipment so, commercially speaking, these machines represent a coup for the supplier. “Of course we’re very proud to have got into Collahuasi but what’s more important for us is the opportunity to be able to show our new customer how we can help, especially when it comes to advanced technology. Of the 40 Pit Viper units in the country, 21 of them feature the RCS system.” says Fernando Depix, Business Manager ADS in Chile. Atlas Copco’s advanced technology was, in fact, one of the major reasons why Collahuasi decided to go with the Pit Viper units: “Atlas Copco offered us the possibility of automated drilling and this is very important for us,” confirms Correa. Complete automated drilling is the way the company would like to go in the future and so it needs to get ready for it: “We have been looking at several alternatives and ideally, in the future, we’ll reach a stage where drilling can be carried out without the operator inside the machine. We have been watching the results at Aitik mine, where they’ve been drilling remotely, with the operator placed at a distance from the machine” he says referring to the Swedish copper mine, one of the most cost-efficient mining operations and where four Pit Viper 351 rotary drill rigs are currently working.

Top left: Fernando Depix, Business Manager, Atlas Copco Drilling Solutions, Atlas Copco Chilena Top right, Paulyn Espindola, Paulyn Espíndola, Atlas Copco Product Manager near a blasthole produced by the PV-351 at Collahuasi. Above: (Group of men from ADS Chile). From left to right: Jean Olivares, Rodrigo Muñóz, Paulyn Espíndola, Fernando Depix, Felipe Ortega, Julio Acevedo and Hugo Moyano.

Continuous improvement and innovation through the use of new technology is another important strategic objective for Collahuasi. “From the drilling point of view, autonomous technology would mean being able to standardise our drilling operations and thus help increase our production,” confirms Correa.

Drilling steel Collahuasi and Atlas Copco did have a relationship before the Pit Viper units arrived at the mine last year. In fact, this relationship started in 2004 and came about through a Cost-Per-MetreDrilled Contract. The agreement entails the supply by Atlas Copco of the whole drilling column: rotary bits (including Secoroc Tricone bits), rotary drill pipes, bit adaptors, top sub adaptors and CENTEROLL rotary deck bushings amongst others. The contract covers a total of 12 drill rigs and different drill diameters, independently of the rock hardness.

In a full year, Collahuasi drills about 925,000 metres in 12 ¼" diameter, plus 420,000 metres in 10 ⅝" diameter and 220,000 meters in 7 ⅞” diameter. All the drill rigs are dressed up with TEAMALLOY drill strings from top to bottom and SMOOTHDRIVE shock absorber sub. The contract, which was recently renewed until October 2014, is based on rate of penetration (ROP) with Collahuasi paying for the amount of metres drilled by the machines in a specific month. “We pay for the metres drilled, not for the steel,” confirms Correa, explaining that if the total drill bit run in a certain month reaches an average ROP over a given base, the cost per metre increases in a percentage according to an agreed formula. On the other hand, if the ROP reached is below the base, the cost per metre is decreased accordingly. “If we manage to get a better drilling rate, we’ll share the savings with Atlas Copco,” says Correa. “The cost saving is produced by the machines achieving a high penetration

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Raising to the Altitude Challenge

we need the supplier to hold some key parts in stock for when we need them,” says Correa, adding that this possibility is currently being discussed. If an agreement is reached, it would be for fast moving critical spare parts; those that the mine would need to use more often.

Future plans & why Atlas Copco

The PV-351 is drilling 12 ¼“ and the PV-271 is drilling 10 5/8” diameter blastholes.

rate, which generates an important reduction in the total drilling cost for the mine,” says Espindola, adding that tests though the PARD system (percussion assisted rotary drilling), show a 35% higher penetration rate when compared with the conventional rotary system.

Maintenance & service Collahuasi prefers to have control over its maintenance operations and therefore these are carried out by its own specialist team. However, when the Pit Vipers arrived, a technical maintenance agreement was struck for Atlas

Pre-split holes 4 ½"

15 m

Drilling pattern at Collahuasi mine.

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Copco to oversee the machines for the first three months. This included two Atlas Copco drilling experts assigned to Collahuasi to support in this area. “Despite the fact that there is no Full Service Contract, we try to be proactive and see to Collahuasi’s needs,” says Eduardo Fajardo, Atlas Copco’s Service Manager MEL – CMDIC. He adds: “We have to be strong in the service area, in technical and customer support, to differentiate ourselves from other equipment providers.” At the moment, Collahuasi would like to have more support with the availability of critical spare parts. “We can’t have a warehouse full of parts, so

Buffer holes 7 7/8"

Production holes 10 5/8" or 12 ¼"

Next year, in 2013, it is planned that work will start in another new area, Rosario Sur 2, which means that a second machine of the same capacity as the PV-271 would be needed. “In fact, next year we have to replace two of the older drilling rigs as they’re coming up for retirement. I’ll be looking for the best machine for our needs,” says Correa. More Pit Vipers for Collahuasi? Judging by the reasons why the mine decided to go with these rigs last time around, there is a fair chance: One of the reasons was the machines’ reliability and prestige. “There are a great number of Pit Viper rigs operating in the Chilean mining industry, which proves that the machines work in our conditions and that there’s enough appropriate support from Atlas Copco,” says Correa. Another reason was capacity; “We couldn’t find another manufacturer that could offer us a diesel rig with such a great capacity as that of the PV-351.” Finally, there’s the subject of technology. “These rigs are now able to drill in automatic mode and in the nottoo-distant future we can upgrade to a full autonomous mode. This was not offered by other manufacturers,” says Correa. When it comes to surface drilling rigs, Atlas Copco’s advanced technology and know-how is setting it apart from the rest. As Depix says: “It’s one of our main advantages, and we’ll use it to help our customers achieve their targets.”

Acknowledgments Article & photographs by Adriana Potts. Technical drawing by Greenwood Communications. With thanks to Collahuasi mine and Atlas Copco Chilena . Blasthole Drilling in Open Pit Mining

USA, Elko, Nevada

Innovation through interaction First PV-271 ever built When the Pit Viper 271 drill was developed, Atlas Copco’s engineering and marketing staff worked closely with customers to design a rig for greater efficiency when the truck and shovel mining method is used. Jim Owen works at Barrick Goldstrike Mine near Elko, NV. He is not a driller or mechanic, but his day-to-day responsibilities give him the experience to know the PV-271 better than just about anyone.

Product development Atlas Copco has a creed that is stated in most internal and external communications. “We are committed to your superior productivity through interaction and innovation.” These are not just marketing words tossed about lightly, but rather a promise of conviction to each customer. However, unlike most marketing statements recited to customers, this statement is also a reminder for employees as to why they are here and what makes Atlas Copco better. If you have looked at purchasing a PV-271, you may have met or talked with Jim Owen. Atlas Copco’s Western US district manager, Jon Torpy, said that just about every company that has purchased a PV-271 in the United States, and several outside of the US, has first visited with Jim Owen about the drill. “Jim has been a great resource for other mines dealing with similar drilling conditions.” For Barrick Goldstrike, Owen is an important part of the rig’s daily operation. Owen said, “I’m responsible for everything below the tophead: shocks, subs, steel, bits, bushings, and preventative maintenance on the drills – whatever is needed. I just keep the drills moving.” Barrick’s Goldstrike mine has four PV-271 rigs and holds claim to the first PV-271 ever built. “After 27,113 hours, two compressors and two rotary heads,”

After consulting with customers, Atlas Copco developed the PV-271 to meet their requirements to increase productivity in open-pit, hard rock mining.

Owen said, “it is still our best performing rig with no cracks in the tower or frame. Where it counts, all is good.” Since it arrived at the mine in 2004, the original rig has been problem free. Other than the replacement of wear items and preventative maintenance, “the first rig went to work the day it was taken off the lowboy and has been drilling ever since,” said Owen. To put that in perspective, that’s a whopping 58,856 holes for a total of 2,671,217 drill ft. Over that period of time the PV-271 has had an average penetration rate of 199 ft per hour. “The rate has stayed constant over the life of the rig, faster when starting a layback and reducing when we go deeper,” said Owen.

Owen is impressed with component life, too. On the first rig he got 10,000 hours totaling 1.2 million drilled feet on the first rotary head and so far 17,000 hours on the second rotary head. Design has had much to do with this. “I really like these drills,” said Owen, emphasizing his personal reason that, “they save me so much work!” He complimented the rig’s smooth operation stating, “It is even easier on bits because not having to add a rod, there is no air loss which sometimes results in back reaming.” One of the features that Owen really likes is the Automatic Tensioning Adjustment for the cables. “As you drill the cable stretches and slackens up. With a smaller drill you’re manually adjusting

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Innovation through Interaction

Jim Owen, Drill Supervisor, plays an important role in the rigs' daily operation and is responsible for everything needed to keep the drills moving.

about once a month or so,” said Owen, who is glad this is not necessary with the longer cables on the PV-271. The task of manually adjusting the tension requires lowering the tower which takes time. With the automatic tensioning feature on the PV-271 the work is done automatically.

Interaction from the beginning The PV-271 was developed to increase productivity in open-pit, hard rock mining. Not only was the entire drilling process examined, but also how it fit with mining operations as a whole. To ensure they hit the mark, Atlas Copco turned to Goldstrike and worked closely with the Goldstrike operations team, which included Jim Owen. Interacting with Goldstrike and other customers during the development of the PV-271 ensured that Atlas Copco developed a drill that met the mining industry’s exact requirements, not just what they THOUGHT was required. For Goldstrike 116

that meant the drills needed op-timum footage, but they also needed to drill to the shovel’s optimum performance. “A 50-ft bench would work great for the shovel, but this size drill is perfect with a 40-ft bench,” said Owen. Increasing the footage rate was a result of completing a full hole without adding or removing drill steel. Efficiencies came with more time over the hole and reduced setup and tramming time. Goldstrike uses two 25-ft steel and one 10-ft sub for a total of 55-ft. Including the ground to rotary head space when jacked up, this gives Goldstrike the required 40 to 46 ft of clean, straight hole. Production drilling at Goldstrike is done with 9⅞- and 8¾- inch bits for trim and presplit work. Owen said, “We changed the breakout wrench because the drill was designed for 7⅝- inch pipe, but we use 7-inch pipe because it’s a better fit for the 9⅞- and 8¾- inch bits – and it’s also cheaper.” Pipe could be an expensive item but because they are not making connections, drill steel

lasts them about eight months. He said when they are finished with the pipe, there is nothing wrong with it other than its diameter is reduced. The wall thickness on the bottom of the 10-ft sub is 2½ inches for extra strength above the bit. Owen said he doesn’t know a guy who would complain about the PV-271 – including drillers and mechanics. “Mechanics can be intimidated with electronics over hydraulics, but it’s so much easier to work on. And once a guy works on it, they find it’s better, not much more difficult than the wiring on your boat trailer,” he said with a chuckle. “I have no problem bragging up the PV-271,” said Owen. “It’s faster, more reliable and the factor of safety…everything just came together on this rig.” When talking about the rate of drilling, Owen said, “I’ve seen one driller get 5,500 ft in one shift.” Today Goldstrike is all rotary drilling with a tricone bit. Owen said, “13,000 ft on a bit is not uncommon and hammer drilling isn’t necessary.” Because the rigs at Goldstrike use tricone bits, a 1900 cfm 110 psi low pressure compressor is all that is needed. Many compressor options are available on the rig, depending on the type of drilling. “Innovation through interaction” are big words describing how the PV-271 came to be. It was mostly guys who use drills sitting down with guys who make drills and saying, “We need a drill that is perfect for what we do.” For those at Barrick Goldstrike, that started with a hole size, required depth and a need to mine gold more efficiently. A couple of years ago, Goldstrike reached a milestone of 30 million ounces of gold mined. “That’s the largest gold removal from any one pit in the world and we’ve mined a couple million since then,” commented Owen. So it’s safe to say the PV-271 is doing its job.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2 2008. Story and pictures by Scott Ellenbecker, Ellenbecker Communications.

Blasthole Drilling in Open Pit Mining

USA, Battle Mountain, Nevada

Unforgiving ground Improvement and teamwork are the keys to success at Phoenix Mine The formation in Newmont’s Phoenix Mine near Battle Mountain, NV, contains high levels of abrasive quartzite but also contains precious gold, copper, and silver. Newmont started mining operations at Phoenix (formerly Battle Mountain Gold) three years ago and the planners knew they were working with a challenging geological formation. But as it turned out, it was more challenging than anticipated.

Hammer drilling with PV-271 Mine manager Mark Evatz said, “Anything that touches Phoenix rock wears fast. The rock fights back here. The Pit Viper is big and bad and can take it.” Evatz is talking about Atlas Copco’s Pit Viper 271 (PV-271) blasthole drill. Because of the hardness of the rock, drilling at Phoenix requires hammer drilling and the mine uses tough Atlas Copco TD65 hammers with 6¾-inch bits. The mine’s PV-271s are outfitted with a single 1450 cfm, 350 psi oilflooded air compressor. Phoenix has six Atlas Copco PV-271 drill rigs plus an Atlas Copco DML and a DM45 midrange blasthole rig. The mine’s goal is to keep four million tons of muck in inventory to stay ahead of the shovels and support needed operational flexi-bility (ore control related). Drilling efficiency has been a continuous point of improvement since operations began at the mine. The singlepass depth capability of 55 ft (16.5 m) on the PV-271 helped with that. Originally, the plans called for 20-ft bench heights, supported by 23-ft drill depths, but time spent moving from hole to hole was eating up productivity. Drilling on

Biting through the hard and abrasive quartzite in the Nevada desert, the single pass Pit Viper 271 gives the Phoenix Mine a clean, 45-ft hole.

that plan resulted in drilling an average of 47 ft an hour. When depths were changed to 44-ft drill depths, supporting blasting of 40-ft benches, they were able to utilize the single pass capacity of the PV-271, and performance increased to over 60 feet an hour. Although the drill depth change largely supported the improvement, other aspects of continuous improvement associated with increased knowledge of the Pit Viper drills helped as well. “We are below our budgeted drill costs,” said Evatz. “This is partially because the best cost- per- foot comes from hammer drilling when in hard rock.” Pat McAmis, maintenance planning general foreman, concurred with this. “You can try to put more drills on the bench, but space and costs don’t make that practical.” The mine focuses on maximizing blast-induced fragmentation while maintaining the integrity of the ore zones (minimal dilution). Although the cr usher can handle 30-inch boulders, McAmis said, “The goal is to maximize what you’re digging – keeping a methodical approach.” At the Phoenix mine, “drills are top priority machines and we mine to feed

the mill,” said McAmis. He is pleased with the performance of the PV-271 and has no major concerns, complimenting the support from Atlas Copco and his distributor, Cate Equipment. “We’re all in it to make money and you have to be fair, but I would say we work well together.”

Time per hole Drill operator Clinton Riddle started in mining in 1976 and has seen a lot of technology advancements over the years. “For me, things really started to change the last couple of years.” He cited that these advancements include the speed of drilling with air, computerized controls, and automation on the rigs. Depending on the formation and area of the mine, Riddle said a 45-ft hole can take 5 to 45 minutes. As he drills, he watches his computer monitor, which tells him the hardness of the rock, the drilling rate, and performance statistics such as time per hole, torque and rotation. The color-coded block on the right of the screen shows red for harder rock formation and yellow or green for softer formation. This helps him anticipate

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NEWMONT’S PHOENIX MINE

Single pass drill of 40-ft benches with PV-271 rigs.

what changes may be required in the hole. He said the color bar is nice to have, but it’s still just a guide. Riddle said the average shift completes about 18 45-ft holes, but there are some eight- to 12-hole days and he’s seen as many as 50 a day. Atlas Copco’s Western Region manager, Jon Torpy, has been in mines all around the world. About the rock at Newmont, Torpy said, “We, as Atlas Copco, have only seen a handful of locations that have the difficult drilling conditions found at Phoenix, and the PV-271, coupled with the TD65 hammers, are the best tools for the job.” Maintenance superintendent Walt Holland is responsible for the entire mine’s equipment maintenance at Newmont’s Phoenix Mine. He said that he looks at mining equipment like a three leg stool – drills, shovels, trucks – and all have to be working to keep things moving. Because of the hardness of the rock, “drill maintenance is very important at Phoenix,” said Holland. Other Newmont properties may drill 120 to 130 ft an hour, but at Phoenix, they are now up to 60 ft per hour. “The rock hardness at Phoenix is unique to the world,” he pointed out. “What I like about the Pit Viper rig is its quality. I am getting 92.5 percent availability and that is really good.” The operators were given additional training required for the single pass rig and they feel very comfortable operating them now. “We have a great history with Atlas Copco 118

and have worked right through any issues that have come up,” Holland said.

Maximum productivity In recent months, productivity at Phoenix has increased and Holland credits this in part to good communication between operations, maintenance, and engineering. “Phoenix is successful because we don’t get conflicting missions. We work well together and challenge each other. The ground is unforgiving at Phoenix and it takes a team approach to be successful. When mechanics and operators are talking, you know you’re winning,” he said with conviction. Mark Evatz echoed this sentiment. “There had to be a steep learning curve at Phoenix,” he said. Since operations began, the most recent quarter was the best at Phoenix from an operation standpoint. “More revenue at a reduced cost has had a lot to do with technology and the application of the Pit Viper rigs,” said Evatz. For Evatz, continuous improvement is a large part of the success at Phoenix. “We had 96 of 100 points right when we started up Phoenix,” he said. A lot of the original planning decisions came from the best practices used at other Newmont Nevada mines, such as the Lone Tree Mine. “We looked at the hardest rock at Lone Tree as a comparison

when beginning operations. Basing equipment estimates and mining practices on Lone Tree’s numbers, our drill production was half of Lone Tree’s,” Evatz said. For another equipment example, Evatz said dozer grousers require replacement three to four times faster at Phoenix than Lone Tree. Although the overall mining rates were comparable at ~150k tons per day, the rock hardness/abrasion at Phoenix is substantially greater. Major consumption items such as down-the-hole hammers and bits are a large ticket item when hammer drilling, but necessary in very hard rock. The mine uses about a dozen TD65 hammers a month and hundreds of 6¾-inch bits. To maximize performance, Atlas Copco has placed a full-time Product Support Sales Representative (PSSR) in the mine to support and develop the use of consumables. Jim Wheeler, Atlas Copco senior area manager for consumables in the Intermountain Region, said, “Having someone on-site is all about continuous improvement.” An example of this was a recent insert change on the 6¾-inch hammer bit’s gauge row, which has increased bit performance. Having someone there watching the performance of all consumables ensures that all pieces are working together, reducing drilling costs and improving productivity. About 150 bits are used per month, and in these extraordinarily abrasive conditions, regrinding is not considered an option. However, in order to reduce bit consumption as much as possible, Secoroc has changed the carbide in the buttons to a tougher grade. Evatz said that incorporating someone from Atlas Copco onto his team has allowed them to share the successes and failures, and has helped fix issues as they come up – the first time. There is no finger pointing, just solutions for Evatz.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2 2008. For this edition the article has been edited and condensed.

Blasthole Drilling in Open Pit Mining

canada, VAL D'OR

Community-friendly mining Smaller rigs and holes mean patterns that limit vibration, noise and dust The mining industry has become increasingly conscientious of the environment and comunities where they operate. Change is driven by mine ownership and management striving to create a better workplace for their employees and develop good working relations with their operation’s neighbors. As manufacturers increase the focus on operator comfort, fuel economy and ease of maintenance, they also contribute to better community relations by engineering products that control noise, dust and vibration.

The Malartic mine

Integrity of the hole is maintained with a cardboard tube: Hole depth is 11.7 m (38 ft 4 ½ inch).

In 2011 Osisko Mining Corporation started production in the Canadian Malartic mine in Northern Quebec, just 40 kilometers west of Val d’ Or in the Abitibi Gold Belt. The open pit proven and probable reserve estimate is 10.71 million ounces of gold. In January 2005 Osisko initiated a detailed compilation of the extensive historical database, including data from over 5,000 surface and underground drill holes. Osisko commenced its own drilling program on the property and in 2007 started open-pit excavations. Full production started in 2011. The mine is expected to produce 250,000 ounces of gold in 2011 and over 700,000 ounces in 2012. The placement of the new working mine is unique because it sits within the community of Malartic. During exploration, core rigs were set up on lawns of residential property. Almost 200 homes needed to be purchased or moved before push-back could begin.

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Community-Friendly Mining

The PV-235 drill rigs are used for drilling of 8.5 inch (216 mm) blastholes with a spacing of 6.3 x 6.3 m.

Osisko Director of Communications Hélène Thibault can recall knocking on people’s doors to let them know when they could expect drilling in their lawns. Starting out, sound and dust presented a problem, mining in such close proximity to the community. An earth berm built to separate the town from the mine did much to solve that problem. Equipment choice also played a crucial role in creating the total community relations solution.

The R in PR If the community did not already embrace the vision of restarting the mine, choice of equipment would be a moot issue. Thibault attributed some of the ease in creating a shared vision to mine personnel themselves. Of the mine’s 500 employees, 45 percent of them come from the community. She said, “The employees are our ambassadors to the community. They

take the message home with them daily so the community knows what we are doing.” For the first time in the history of Quebec mining, and even though it is not required by law, Osisko deposited $22 million with the Quebec government, which is half of the future cost of rehabilitating the Marlartic site. The balance will be paid by 2013. Osisko took the initiative as a part of its socially responsible attitude and in order to assure local residents the mine would not be abandoned for the government to clean up.

Reducing vibration and dust

The PV-235 cab is offering phenomenal visibility and comfort.

120

The company chose the newest Atlas Copco Pit Viper model available, the PV-235, to drill 8.5 inch blastholes. These smaller holes are placed closer together in a blast pattern that has less impact on the environment. “The idea is to have no dust or vibration outside the mine,” said Mine Manager François Vézina. The mine has purchased 300 blast mats to reduce noise, shock and debris and expects to purchase 100 more. Vézina appriciates the automation and precision advantages that come with the RCS system on the rig. The Blasthole Drilling in Open Pit Mining

Community-Friendly Mining

auto-drilling system starts off slower when collaring the hole, which also reduces ambient noise. Planning each day starts with the weather forecast, especially wind direction. The mine cannot have dust carried into town, yet the crusher needs to be fed. The wind is also a factor in carrying noise. The PV-235 size reduces both of these problems. The mine was blasting 150,000 tons per day and expected with increases in equipment to be up to 250,000 tons a day by the beginning of 2012. Osisko operates with a 2:1 waste to ore ratio. The pit is projected to be 3.2 kilometers by 1 kilometer with a 400 meter depth. To assist in controlling the blast, the pattern is 6.3 meters by 6.3 meters by 10 meters. The goal is to create the smallest rock possible using a smaller pattern.

Driller Mathew Leeker said it took him just one to two weeks to catch on with the operator friendly drilling system. Previously he was diamond driller. Like all drillers on the PV- 235, Leeker very much enjoys the cab's comfort.

Rebirth of a town The opening of the Malartic mine has been a boon to the small community. Although the town is on the main road leading to Montreal, it was just a town to drive by. With the investment from the mine of new neighborhoods and a $16 million elementary school construction, the town of 3,000 is now growing again. Thibault said, “We consider ourselves guests, and we want to leave the town better off. Originally the budget was $15 million for the school, but because the architect said $16 million would give us so much more, we spent $16 million. These are our future miners. We want to give the kids the best quality of life and education.” The mine also committed to an annual improvement fund of $50,000. Thibault said, “We don’t think of this as buying the community’s appreciation; we want the community to win from the gold found here, too.” Safety was also a long-term consideration. Once a neighborhood of depreciated housing because of the abandoned underground workings, homes have been moved to accommodate the new mine workings. The homes were purchased at fair market value and are now in a healthy area where kids ride bikes and play in the streets safely.

Adding to the four PV-235 rigs already working, the mine has purchased three additional rigs.

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Equipment decision While making their equipment decisions, they kept one focus in mind: Choose technology for the future. “We knew we were taking a chance with new-model equipment, but we are in this for the long term and going with Atlas Copco’s experience was important to us,” said Vézina. In total there are nine drills working onsite, with many exploration drills doing reverse-circulation and core drilling. It is expected the mine has a 16-year life, but the exploration is continuing and there is hope that it will go further. Adding to the four PV-235 rigs already working, the mine has just purchased three additional rigs. Recently Vézina signed a three-year service contract with Atlas Copco to maintain the drills. “Those Atlas Copco service techs really do a good job and know what they are doing.” The commitment from Osisko is not just for 16 years, though. “This is a partnership,” said Vézina. “I think we need to have a partnership philosophy with suppliers and the community. We learn from our partners. I’m proud of what we are doing here. And we are going to have a lot of fun.”

Acknowledgements Photos and story by Scott Ellenbecker, first published in Atlas Copco Mining & Construction magazine, No. 3, 2011

The Rig Control System (RCS) makes life easier for Mathew Leeker.

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The Pit Viper 235 has a weight on bit of 65,000 pounds and is designed for rotary or DTH drilling of 6 – 9 7/8 inch (152 -251 mm) diameter holes. Two tower options are available to drill 35 ft (10.7m) or 40 ft (12.2m) clean holes.

Blasthole Drilling in Open Pit Mining

argentina, andes mountains, San Juan Province

Drilling reliability at Veladero

Operations at Veladero take place at altitudes of between 4,000 and 4,850 metres above sea level.

Heroes of Veladero Working amidst some of the harshest weather conditions and where maximum reliability is paramount, the PV-271 drilling rig is proving its worth at the Veladero gold mine in Argentina.

As mining operations go, you would be forgiven for thinking that Veladero is just another conventional, low grade open pit gold mine. This is true to a point. However, look closely and you will find a fascinating history and some amazing logistics, making you marvel at the everyday challenges faced by workers and machinery to make this a successful mining operation. The Veladero Mine is operated by Minera Argentina Gold S.A. (MAGSA), a subsidiary of Barrick, one of the world’s leading producers of gold.

Located in San Juan Province, about 350 km northeast of the city of San Juan, Veladero is in the high Andes at an altitude between 4,000 and 4,850 metres above sea level. It is very close to the Chilean border and immediately south of the Pascua Lama gold project, which straddles the border between Chile and Argentina and is currently also being developed by Barrick. Veladero is accessed by a purposebuilt 156 km road which passes elevations of over 5,000 metres above sea level. Depending on the weather conditions, it takes about seven hours in a 4x4 vehicle to drive from San Juan, the nearest city, to the mine. Conditions can be so severe that special shelters have been built every 20 kilometres along the access road to safeguard workers and travellers in extreme weather. At this altitude, the temperature is highly variable and drops 2° for

every 300 metres in elevation. During winter, which takes place between July and September, the average daily temperature is -10°, dipping as low as -16° during the night. Add to that the wind chill factor and the night time temperature can drop to -40°, a figure that has been recorded several times. “Winds blow from west to east and can be very strong, sometimes 80-100 km/hour. Even extreme winds of up to 220 km/hour have been recorded by the weather station,” says Jose Luis Fornés, Mining Superintendent at Veladero, explaining that the average winds are 20-30 km/hour during the day but that this increases substantially as the day wears out. “Weather conditions can be very hard, especially in winter, to the point where the access road can be blocked and us having to declare an alert,” says Fornés, explaining that among its facilities, the mine has an operating

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To the left, Veladero drilling pattern: hole spacing of 7x8 m in waste and 6.5x7 m in ore. To the right, rock sampling: Veladero has a silica-type rock whose hardness and compression varies throughout the site.

theatre with a surgeon, should any medical emergency happen whilst the road is closed. Because of the remoteness of the mine, operators at Veladero work a pattern of 14 days in and 14 days out. Of the 14 days at the mine, seven are worked during the day and seven are worked during the night. “We have special conditions here that complicate our logistics. There’s nothing within a 100 km radius around us, so we expect reliability from our equipment and suppliers,” says Fornés .

History Although mining activities around the San Juan Province can be traced as far back as the early 19th Century, Veladero represents the arrival of true, large-scale mining to this part of Argentina and it is Barrick’s first operation in the country. After a programme of regional exploration in the mid 1990s, it was not until May 1997, in the middle of snow storms and cut off roads, that gold and silver was discovered in an area 124

called Federico. The winter of 1997 was especially bad due to the El Niño weather phenomenon, making it even more difficult to access and continue work in some key areas. After four years of exploration, in 1998 two very significant holes were drilled in an area called Amable; Hole V76 in May and Hole V90 in October, which revealed excellent mineralisation and showed the quality of the project. Soon after this, MAGSA’s then parent company, ARP, sold its shares to Homestake Mining Company, which in turn merged with Barrick in 2001. The environmental impact assessment for Veladero was approved in November 2003 and that same year construction started. After an investment of US$540 million in the construction of the mine, commercial operations finally began in September 2005 and the first gold bar was produced in November that year.

Mining & processing operations Veladero is an open pit mine extracting gold and silver from three orebodies:

Filo Federico, Amable and Argenta. Federico, to the north and Amable, to the south, are the original open pits. Extraction at Argenta, located in the southeast sector of the field, commenced in 2010. Exploration has been carried out at a fourth area, Cuatro Esquinas, which is located in the centre and will eventually become a working pit. Veladero is a low grade mine producing about 1 gram of gold per tonne of rock with an ore to waste strip ratio of 3:1. Metal recovery is achieved through heap leaching and cyanide processing methods. Veladero’s gold production in 2011 was 0.96 million ounces of gold at a total cash cost of US$353 per ounce. Proven and probable mineral reserves currently stand at around 11.3 million ounces of gold. Rock extraction is car ried out through drilling & blasting with the mine currently extracting an average of 230,000 tonnes/day of rock. Higher grade ore is crushed to 32 mm size in a two-stage crushing process and then transported via overland conveyor and trucks to the leach pad area. On the Blasthole drilling in open pit mining

Drilling Reliability at Veladero

To the left, the PV-271 is drilling 10 5/8” production blast holes at Veladero. Top to the right, Carlos Cavanillas, Drilling & Blasting General Supervisor (left) and Ramón Arjona, Drilling & Blasting Senior Supervisor. Bottom to the right, Veladero employs standard 15 m high benches.

other hand, very low grade, run-ofmine ore is hauled directly to the leach pad area. All the ore is then stacked in a lined containment area behind a retention dam. A cyanide leach solution is applied to the top of the stacked ore and allowed to percolate through the heap. As the solution goes through the ore, it dissolves gold and silver from the rock. This gold-rich solution is collected at the base of the leach pad and pumped to a conventional Merrill-Crowe process plant in order to recover the gold and silver. Through 2007 and 2008 Barrick offered a US$10 million prize to the scientific community in a bid to improve silver recovery at Veladero. Recovery rates for silver are low, less than 7%, because the metal is bound within silica, which is difficult to dissolve using conventional cyanide processing. As many as 130 proposals were submitted and of these, nine were selected for testing. “Ever since we started operations, we’ve been looking for ways to increase production,” says Fornés, explaining

that crushing capacity was expanded from 50,000 to 85,000 tonnes/day in 2009. Heap leaching capacity as well as transport have also been increased. Power at the mine is provided mainly by diesel generators with a total capacity of 13.5 megawatts. In 2007, the company installed a wind turbine which currently produces 2 megawatts or around 20% of the total electricity needed to power Veladero’s operations. “The use of wind energy provides a clean source of power for the mine and also helps us to cut down on fuel transport,” says Fornés, explaining that the wind turbine, which took nearly a month to assemble, weighs 229 tons, has a rotor diameter of 80 metres and is installed on a specially-developed tower nearly 60 metres high. At 4,110 metres above sea level, this has been recognized by Guinness World Records as the highest wind turbine in the world. Veladero uses a mine management system as well as a wireless communications system for increased data bandwidth throughout the site and field communication.

Drilling & blasting Carlos Cavanillas, Drilling & Blasting General Supervisor and Ramón Arjona, Drilling & Blasting Senior Supervisor, explain the daily work routine for their area. “We have a daily meeting first thing in the morning to check what the night shift is leaving us with; for instance, if there were any incidents or problems with the machines,” says Cavanillas. This is followed by a visit to the working area for a general inspection. “We check the areas that are going to be blasted that day and determine whether there will be blasting or not,” says Arjona, explaining that normally, blasting happens twice a day, at 2:00 pm and then again later on at around 6:00 pm.Veladero uses ANFO for blasting. The severe weather can interrupt the operations. Indeed, as Cavanillas points out, they get an updated weather report every single day: “If there’s the possibility of a thunderstorm that day, we don’t blast - it could be catastrophic!” Veladero’s current drilling fleet is composed of 11 diesel rigs, some drilling

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Drilling Reliability at Veladero

Other Atlas Copco equipment at Veladero includes a ROC F9 crawler drill rig.

pre-split holes and some drilling production holes. This includes an Atlas Copco Pit Viper 271 and a ROC F9 unit. There are also four DM-M2 rigs amongst other machines. The ROC F9 rig, which has been working at the mine about a year longer than the Pit Viper machine, is currently working in production, drilling small 4” holes. “It’s possible that we will use this machine for pre-splitting in the near future,” says Arjona, explaining that there is another ROC F9 unit, with similar configurations working on presplit drilling at nearby Pascua Lama. “We’ve heard that machine is doing very well,” he says. The PV-271 rotary drill is also working in production. Before acquiring it, Cavanillas wanted to see a similar rig under working conditions: “Ramón and I went to Chile, where we had the opportunity to see the PV-351” he says, referring to the largest model in the Pit Viper series. Several of these units are working at Codelco’s Radomiro Tomic copper mine, 3,000 metres above sea level in the Atacama desert of northern Chile. They were impressed by the performance of the PV-351 and after discussions, decided that the smaller PV-271 was the best option for Veladero.

PV-271 in action

Ramón Arjona, Drilling & Blasting Senior Supervisor with the PV-271 drill rig.

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The PV-271, which arrived at Veladero in May 2010, is currently deployed in Pit Amable drilling 10 ⅝” production blast holes to a depth of 15 metres. The mine employs standard 15 metre high bench drilling with a hole spacing of 7 x 8 metres in waste rock and 6.5 x 7 metres in ore. A sturdy and powerful blasthole drill rig, the PV-271 features a pulldown force of up to 311 kN (70,000 lb) and a 34 tonne (75,000 lb) bit load capacity for maximum productivity in hard rock formations. Veladero has a silica-type rock whose quality varies throughout the site. “We have areas where the rock is hard, others where it is quite fragile and others where it is not only hard but also highly compressive,” says Arjona. Victor Astudillo, the operator of the PV-271, knows this only too well. He Blasthole drilling in open pit mining

Drilling Reliability at Veladero

explains that depending on the area where they are working, drilling a production blasthole can take anywhere from 18 minutes to one hour: “Most of the rock is hard so on average, it takes about 45 minutes to drill a hole.” As all the machines in the Pit Viper series, the PV-271 uses Atlas Copco’s hydraulic cable feed system, which is lighter than the traditional chain feed option. This leads to overall weight reduction in the tower and feed system and to smoother drilling, which in turn extends both bit and feed system life. “Feeding and retracting for pulldown and pullback is really fast so I can spend more time drilling,” says Astudillo. Astudillo, who has been a drilling operator for four years and has experience working with the DM series, is pleased with the ergonomics of the rig: “it is amazing how comfortable it is. There could be dust and noise outside but you barely feel it inside here,” he says, adding that he also likes the fact that the drilling and non-drilling controls are separated: “it certainly makes the machine easier to operate.” Working at high elevations can present a number of problems for any machine. With every additional metre in elevation, air density and pressure decrease and traditional electronic components no longer function reliably. “Also, our severe winter can affect a machine drastically,” says Arjona, explaining that some areas of the machine such as the air and water circuits can easily get frozen. So, in order to work under the weather conditions at Veladero, the PV-271 had to be equipped with several special features such as a more powerful engine and compressor but also with a cold weather package, which includes additional covering of the machinery housing and allows for warm start-up and drill operation in extremely cold ambient conditions. And how has the PV-271 faired in this harsh environment? “Oh, very well indeed and with good reported availability times, too,” says Arjona, explaining that when comparing forecast versus real availability and utilisation in the monthly report, the real figures normally come on top.

PV-271 operator Victor Astudillo says that due to the variable quality of the rock, drilling a production blasthole can take anywhere from 18 minutes to one hour.

“The PV-271 has given us good levels of availability. We can rely on that machine, and for us that’s what’s important,” says Cabanillas. According to Fornés, when choosing new equipment for the mine they take into account some basic parameters, such as the machine being able to be fitted with specific features for cold weather or the machine’s penetration rate. But in the end, it is the total cost of owning that machine which is going to tip the balance for Veladero: Cost of buying the equipment itself, cost of operating it and cost per hour. “Whichever equipment gives us the best results, that’s the one we’ll go for and in this case it was the Pit Viper 271.”

Motivated by technology The PV-271 is poised to please Veladero even more once it is fitted with the Rig Control System (RCS) technology; this will give the mine a series of highly automated options, including: Autolevelling, Autodrilling, GPS Hole Navigation, Desktop Viewer and

Communication, Wireless Remote Tramming, Measure While Drilling and Teleremote Operation. Autolevelling increases quality in set up of the drill. Depending on the ground conditions levelling can be done in less than 35 seconds with an accuracy in pitch and roll to 0.2 degrees. Autodrilling allows the system to react to the different rock conditions within one blasthole and adjust the drilling as necessary. This feature provides the consistency of drilling to the correct hole depth, and a consistent water f low to maintain the hole so it does not collapse. GPS Hole Navigation ensures the blasthole is positioned where it has been designed in the blast pattern and it is drilled to the correct depth. RRA and Communication connects the drill rig to a standard computer network on a work site and allows access information on the drill rig from any authorised point in a network. Wireless Remote Tramming gives the operator f lexibility to tram the machine from the bench within a 60-metre distance. Measure While Drilling logs several drill parameters during operation; this data

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Drilling Reliability at Veladero

Atlas Copco and Veladero staff together (from left to right): Miguel Sernaqué, Atlas Copco Drilling Specialist; Carlos Cavanillas, Drilling & Blasting General Supervisor; Victor Astudillo, Drilling Operator; Ramón Arjona, Drilling & Blasting Senior Supervisor and ADS Technician Osvaldo Gil from Atlas Copco Argentina.

can be used for prediction of geological and geochemical variations within drill patterns on a bench. Teleremote operation uses the mine’s wireless network and allows an operator to utilize the machine functions mentioned before from a remote location. “We’re going for the full set of RCS functions and are looking forward to using this technology at Veladero,” says Cavanillas. Upgrading the rig entails replacing the cabin with a new one. “During this time the machine won’t be able to operate, but the changes will be well worth it,” says Atlas Copco Drilling Solutions Technician Osvaldo Gil, adding that when the modification is finished, an Atlas Copco factory specialist will be there for 10 days to train the operators and mechanics and to make sure everything works well. “They’re not used to operating with joy sticks; this will be 128

something new for them,” says Arjona, explaining that they want to use this opportunity as an incentive for the drill rig operators: “We want them to learn and then to ‘earn’ the right to operate the machine.” This training will be put to another good use for a second PV-271 now on order for delivery to the mine. Effectively, the managers at Veladero are so pleased with the performance of the drilling rig that they have decided to acquire a second unit and this time it will feature RCS technology from the start. “The idea is that both machines will have the same configurations, avoiding the need for different spare parts and operations,” says Gil. With both machines, the one being upgraded and the new one, featuring full versions of the RCS system, Veladero will be able to take its drilling

to the next level. “The technology from Atlas Copco is another factor that keeps us motivated,” says Cavanillas, adding: “Eventually, our idea is to work with the Pit Viper remotely from a fixed distant point. We want to be at the forefront when it comes to mining technology.” Using the latest high technology in drilling automation will certainly help Veladero achieve this goal. “And if everything continues to go well, our vision is to eventually replace all our DM machines with Pit Vipers.” And to ensure that everything will go well, Atlas Copco has a Technical Assistance Contract with Veladero, which was put in place in April 2011. The contract, which has just been renewed for another six months, specifies one specialist drilling technician from Atlas Copco available to Veladero per shift. Currently that means two people, each working seven hours shifts. “We’re here to help with any drilling issues that might come up. We spend time with the rig operators and the drilling supervisors, giving technical support to all the Atlas Copco fleet, not just the PV-271 but also the ROC F9 and the four DM-M2 units,” says Miguel Sernaqué, one of the Atlas Copco drilling specialists. Once the new PV-271 arrives, the plan is to have two technicians per shift, effectively four people, available to Veladero. Servicing Veladero will go even further now that Atlas Copco Argentina has just expanded its operations and presence in the region with a new branch and workshop located about 2 km south of Barrick’s offices in San Juan. Gil explains that the new branch offers all types of after-sale services as well as evaluation, failure analysis, repair of equipment and major components, field equipment set-up and the stocking of key spare parts. He says: “We’re here to see to Veladero and Barrick’s needs; that’s our priority and commitment.”

Acknowledgements Articles and photographs by Adriana Potts. With thanks to Veladero mine and Atlas Copco Argentina.

Blasthole drilling in open pit mining

MEXICo, saltillo, ZACATECAS

Penasquito powers up

Powerful fleet: Five of the seven Atlas Copco Pit Viper 351 blast hole rigs lined up at the Penasquito open pit gold mine.

A perfect match for large hole drilling. In just 14 months the site of the Goldcorp Penasquito mine in the state of Zacatecas, Mexico, was transformed from a flat open valley into a mine producing more than 500,000 tons of rock each day. Its choice of Pit Viper drills and Secoroc drill pipes and tricone bits has proven to be the perfect fit.

A total community program Peñasquito is Mexico’s largest open pit mine and comprises the Penasco and Chile Colorado/Azul deposits that contain gold, silver, lead and zinc. At an elevation of 1 900 m above sea level, the surface of the site is made up of approximately 30 meters of alluvium.The virtually flat topography has helped the mine carry out its development plan that includes moving large amounts of rock. “I’m used to mining in mountains so this is easy mining by comparison,” says Mine Manager, Tim Collins. The company reports that annual production over the life of the mine

(estimated to be 22 years) is expected to ramp up to approximately 500 000 ounces of gold, 30 million ounces of silver and more than 400 million pounds of zinc. The Peñasquito project is considered a total community improvement program that includes educating future generations by building schools. When looking for potential employees in the surrounding area, Peñasquito found that most of the local inhabitants had no mining experience or even a driver’s license. Today, however, 70 percent of Peñasquito’s truck drivers are local women, many of whom had never driven before, and now work at the mine as a result of Goldcorp’s investment. In addition, operating millions of dollars of earth moving equipment required an intensive training program before the workers entered daily production.

Powerful fleet From the outset, it was the mine management’s vision to achieve a high level of production, but first it was necessary to find the right combination of equipment and support for the project. To drill and blast half a million tons of

rock every day, the mine needed a special drilling fleet and rig management program. The mine uses only Atlas Copco drill rigs which include seven Pit Viper 351 blast hole drill rigs plus a DML and an ECM 590 for specialized tasks. Production hole size is 311 mm (12 ¼ inches) for the 15 m (49 ft) bench height. Different types of Atlas Copco Secoroc epsilon tricone bits are also used, depending on ground conditions. The entire drill string, including the pipe, stabilizers, bushings and subs are supplied by Atlas Copco Thiessen. Learning to operate the rig also required extensive training, but it takes time to learn the ‘feel’ of the ground. To speed up this process, Peñasquito chose rigs with Atlas Copco’s Rig Control System (RCS), which simplifies the drilling functionality for the operator.

They have it all “These drills have it all,” says Mine Manager Collins. “The operator only needs to move it and level it and the rig drills its own hole.” Collins adds that he does have four experienced drillers

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who like to drill manually and they can match the auto-drilling performance. “There are times when the bit can take more down pressure and less rotation; a skilled operator can feel that,” said Collins. The Rig Control System (RCS), integrates common drilling functions such as collaring a hole with low pressure air and down pressure, applying just the right amount of water and antijamming, with several high-tech options such as GPS hole navigation.

Ensures efficiency Drilling and blasting half a million tons of rock every day: The Atlas Copco Pit Viper 351 drill rigs in operation at Penasquito. The RCS system ensures efficient drilling and the software provides several standard safety interlocks.

RCS ensures efficient drilling, but many features are also for the safety of the miners and equipment. These include jack and tram interlocks which ensure that the rig and tooling are secure before a rig can move. The mine has installed a complex dispatch system that integrates with the GPS on each haul truck, shovel, drill rig and every other piece of mining equipment. The entire operation is monitored from a control room where two dispatchers and a maintenance person watch and direct the activity in the mine. All data is recorded and is retrievable by those in the mine who need constant equipment information. However, the operation can also be monitored in real time through a web-browser interface anywhere in the world.

Technology is the future

The single pass Pit Viper 351 will drill 50 holes per 12 hour shift, at the 15 m (49 ft) high benches.

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“Technology is the future of mining,” continues Collins. “If you’re monitoring maintenance and operational data to this level, decisions are made when they need to be made. Mining is more efficient today than it once was – technology has a lot to do with that – and safety can only move forward at the same time.” When searching for the right equipment, Alan Hernandez, Project Engineer, Technical Services, and Tim Collins, spent seven months travelling around the world trying to decide which products would fit the program. “There were some hard decisions, but for drill rigs it was always Atlas Copco,” said Hernandez. More time was spent debating which Atlas Copco drill models would best fit the plan. Blasthole drilling in open pit mining

Penasquito powers up

Making the most of bits: Xavier Garcia, Key Account Manager, Atlas Copco, trains operators on the correct use of the eH64OA Secoroc epsilon Tricone bits.

“We looked at feasibility studies, calculations, pit design, tonnage – every scenario that would determine what would work best,” says Collins. “For most equipment it was a matter of elimination. The choice consistently came down to service and support, but with Atlas Copco there was no debate. “As far as drilling goes, everything here comes from Atlas Copco,” he adds, complimenting the speed and penetration rate of the Pit Viper 351. “The 351 will drill fifty holes per twelve-hour shift.” The fleet at Peñasquito drills an average of 2,300 to 2,500 holes perweek. To keep ahead of the crushers, about 15 million tons of inventory are kept in the pit. “I like to keep at least a month ahead,” says Collins. This inventory allows time to support the drills. “The maintenance plan includes having two or three rigs serviced for preventative maintenance. That takes care of normal wear and tear. I can say the Cummins engines in all our drill rigs are solid, they don’t even burn oil.”

Close support

Acknowledgements

In addition to parts and training, Xavier Garcia, Atlas Copco’s Key Account Manager for Goldcorp, personally handles drilling consumables at the mine. “Twice a month, Xavier spends nearly a week here analyzing bits. Sometimes it feels like he practically lives here,” says Collins. Atlas Copco’s Marcus Pantoja and Octavio Garcia (Service Manager and Product Specialist) also play a key role, providing training, equipment start-up, commissioning and technical support. To date, the epsilon tricone bit line has changed from eH53CA to eH61 CA, eH62OA and eH64OA, to adjust to the rock formation. “We are constantly reviewing bit wear and performance. We’ll keep testing bits until we settle on the one that works the best,” he says. “A great advantage has been the use of the TeamAlloy Drill Pipe from Atlas Copco Thiessen, which seems to last forever.”

This article first appeared in Atlas Copco Mining & Construction magazine No 3 2009. It was written by Scott Ellenbecker after a visit to the mine in September 2009. The Peñasquito mine will have a long life. As of December 31, 2008, proven and probable gold reserves totalled 17.4 million ounces. Silver reserves totalled 1 045.7 million ounces, while lead and zinc stood at 7.07 million tons and 15.36 million tons respectively. Measured and indicated gold resources, inclusive of proven and probable reserves, increased 39 % to 17.8 million ounces. Measured and indicated silver resources increased 55 % to 1.3 billion ounces. For further information and the latest updates visit: www.goldcorp.com

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Penasquito powers up

Example of Pit Viper 351 Drill String used at Penasquito

Shock Sub Drill Pipe Lifting Bail

Top Spindle Sub

TM

TEAMALLOY Drill Pipe

TEAMALLOY

TM

Starter Drill Pipe

CENTEROLL

DURALLOY

EZ-DRILL

TM

TM

TM

Deck Bushing

Bit Sub

Roller Stabilizer

Secoroc Tricone Drill Bit

Bit Breaker Basket

Drill string Production hole size

311 mm

12 1/4 in

Bench heigh

15 m

49 ft

Secoroc epsilon Tricone Rotary drill bits

H61CA, eH62OA, eH64OA

The entire drill string from the rotary head to the tricone rotary drill bit is supplied by Atlas Copco Thiessen and Atlas Copco Secoroc.

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Blasthole drilling in open pit mining

Turkey, Usak

Secoroc hammers go for gold Secoroc COP Gold hammers The number of meters drilled is directly tied to the productivity level of a mine. The type of rig, hammers and bits must be able to handle the geology of the site while achieving the desired performance levels – and do so costeffectively.

Powerful drilling, reliable production To accomplish this, Tuprag Metal Mandencilik San. Tic. A. (Tuprag) uses Secoroc COP Gold DTH hammers on two Atlas Copco DM45 rigs and a ROC L6 at the Kisladag gold mine. Designed for the production drilling market, Secoroc COP Gold hammers feature a specially designed piston for efficient energy transfer; control tube suspension with steel disc compression rings and lower buffer rings; steel grade hammer casing that provides greater impact strength and excellent wear resistance; and superb flushing capabilities. Secoroc COP Gold hammers have proven to be efficient, reliable and durable with a 10-15 percent longer service life than equivalent hammers. Furthermore, with the COP Gold E-kit, they can be rebuilt and restored to their original performance levels up to three times at a fraction of the cost of a new hammer. These factors, along with intensive training of local operators and maintenance personnel, have seen productivity levels increase beyond expectations since the mine opened in 2006.

Secoroc hammers on the job At 157 km², the Kisladag gold mine in the Usak province of western Turkey is the largest gold mine in the country. It is owned by Tuprag Metal Madencilik San. Tic. A. (Tuprag), a wholly owned subsidiary of Eldorado Gold Corp.

Kisladag Mine Manager Ahmet Raci Uslu in front of one of two Atlas Copco DM45 rigs that enables his team to surpass productivity expectations.

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Secoroc hammers go for gold

B

A

C

C

C

……

10 m

A = 22 m Pre-split holes B = 11 m Buffer holes C = 11 m Production holes

Be rm

Pre-split holes

Buffer holes

10 m

Production holes

1m 4.2 m 2.5 m

5.5 m

4.2 m 5.5 m

4.8 m

5.5 m

10 m

The drilling pattern at the Kisladag open pit with 152–165 mm production holes, 152 mm buffer holes and 95 mm pre-split holes. The purpose of the pre-split holes and the row of buffer holes is to ensure the stability of the final walls of the pit.

The ROC L6 with a Secoroc COP 34 DTH hammer drills the pre-split holes. Each hole is 95 mm in diameter with an average depth of 45 m. Hole spacing is 1 m. (Inset) the blasting sequence of the pre-split holes.

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Tuprag uses two Atlas Copco DM45 rigs equipped with Secoroc COP 64 Gold DTH hammers for bits with a QL60 shank. In addition, there is an Atlas Copco ROC L6 equipped with a Secoroc COP 34 DTH hammer for bits with COP 34 shanks for presplitting, or a COP 54 Gold DTH hammer for bits with a QL 50 shank for production. The result is reliable performance on the site that has continuously increased production from 70,895 ounces in 2006 to 109,177 ounces in just the first six months of 2009. The grade is 1.41 gram per ton.

Maintaining productivity Kisladag started commercial production in 2006 with a local mine contractor and has been developed as a low grade, bulk tonnage open pit operation using heap leaching for gold recovery. In May 2008, the mine began the transition to being a fully owner-operated pit. The transition, which included technical and practical training of operators and maintenance crews, was completed in four months, and the mine began using its own fleet exclusively in October 2008. Kisladag has been using Atlas Copco rigs with Secoroc hammers and bits since the transition began. Penetration rates are good through the volcanic rock and Ahmet Raci Uslu, mine manager, says the rigs and rock drilling tools were selected to maintain the high productivity rates required at the mine. “The amount of meters we drill is really important for us to keep up mine production,” says Uslu. “In June 2009 we drilled nearly 48,000 meters and we aim to maintain this level of production. High productivity is one of the reasons we chose Atlas Copco.” The anticipated production capacity at Kisladag is 1.73 million tons a month, but the current rate of mining is more than two million tons per month. To achieve this, drilling operations are run for 20 hours a day; mining operations are 10 hours per shift and there are 14 shifts per week. A ROC L6 equipped with its Secoroc COP 34 DTH hammer averages 45 m per hour drilling pre-split holes. Hole diameters are 95 millimeters and the Blasthole drilling in open pit mining

Secoroc hammers go for gold

spacing between the holes is 1 meter. The holes are 22 meters deep and have an inclination of 65-77 degrees. For production drilling, the ROC L6 with the Secoroc COP 54 Gold hammer averages 400 meters per shift. Each DM45, equipped with a Secoroc COP 64 Gold hammer, averages 31-35 meters per hour. The hole diameters are 152-165 millimeters and the drilling pattern is 5.5 meters x 5.5 meters with vertical holes. The production drilling benches are 10 meters high with 0.5-0.8 meters of sub-drilling. The total drilling capacity for all rigs is 58,000 m/month. This is including 2 x DM45 and one ROC L6. The availability of the rigs is 92%. Hole quality is checked by measuring tape before each blast. Kisladag uses cord, downhole delays and surface delays for detonators and ANFO and emulsion ANFO explosives. While high speed drilling increases the number of holes completed per day, air consumption, fuel costs, penetration rates and bit and hammer life have a major impact on profitability. The operating life for the Secoroc DTH hammers with E-kits is: COP 34-9,900 meters; COP 54 Gold-12,853 meters; and COP 64 Gold-27,332 meters.

Maximizing, extending bit life Kisladag uses Secoroc drill bits to achieve high production rates for extended intervals. To utilize the full power of the drill rigs, regular bit grinding is essential. The bit on the COP 34 averages 1,540 meters; the bit on the COP 54 hammer, 2,257 meters; and the bit on the COP 64 Gold, 3,099 meters. However, the economics of drilling often comes down to balancing penetration against bit life. A rule of thumb is that a 10-percent increase in penetration rate results in a reduction of 20 percent in bit life. To extend the life of its bits and maximize the number of drilled meters per bit, Kisladag uses a Secoroc Grind Matic grinder, and each bit is reground two or three times. The efficient grinders extend the service life of the bits, which also results in less wear and tear

Bahadir Ergener, RDT/GDE product manager, Atlas Copco-Turkey, demonstrates how to use a gauge to determine when a tungsten carbide bit needs regrinding. Kişladağ uses a Secoroc Grind Matic BQ2-DTH.

on each rig’s drillstring. The availability of consumables and parts, as well as the durability of the equipment, also played a role in Ahmet Raci’s Uslu’s decision to use Atlas Copco at Kisladag. “We have our own maintenance shop and crew. We get good maintenance support from Atlas Copco Turkey and a good supply of parts and consumables – that makes life easy for us,” he says.

Exceeding productivity expectations Since the first year of commercial production (July 2006), Kisladag has surpassed productivity expectations. Initially, plans were to increase production in year four, but Tuprag was able to move forward with expansion in year two. And the trend continues. Tuprag’s parent company, Eldorado Gold, recently completed a review of the

Kisladag mine. The study identified opportunities to effectively increase annual production by 30-40 percent, while decreasing unit operating costs by approximately 15 percent – all of which is expected to be achieved using Tuprag’s existing fleet. For Ahmet Raci Uslu, the relationship with Atlas Copco and the reliability of the equipment will continue to contribute to the production capability of Kisladag. And with Secoroc equipment offering the lowest cost per meter in the industry, taking all costs into consideration, his fleet will also make a major contribution to the mine’s profitability.

Acknowledgements This article first appeared in Mining & Construction, No. 3 2009, and was updated June, 2010.

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Secoroc hammers go for gold

Kisladag to double its gold Arrival of Pit Viper 235 In mid 2011 the Kisladag mine took delivery of a new Pit Viper 235. This is a high pressure unit used for single pass drilling of 12 m deep blastholes using a Secoroc DTH hammer. Here is an update published in Mining & Construction No 2 2012.

Team of rigs High on the Anatolian plateau, Canadian company Eldorado Gold Corp has successfully commissioned its Kisladag gold mine. Operated through Eldorado’s subsidiary, Tüprag Metal Madencilik Sanayi ve Ticaret, the mine opened in 2006 and is now Turkey’s No.1 gold producer with an annual production of about 285 000 troy ounces. In contrast to the volcanogenic massive sulphides of the Black Sea region, the ore at Kisladag is in porphyry-type mineralization. It grades up to 1 g/t gold. with softer, oxidized material at a depth of 30-80 m. Serkan Yüksel, Mine Manager at Tuprag, explains that the company plans to more than double its ore production by 2014. Since Tüprag took over mining from a contractor in 2008, the operation has relied on two Atlas Copco DM45 blasthole drill rigs for production drilling. Then in mid-2011, it took delivery of a new Pit Viper PV-235. Together, the three rigs completed 650 000 drillmeters in 11 months. “That’s over 58 800 individual holes,” notes Yüksel, “and during the first four months, the Pit Viper contributed around 70 000 m to that total. We are using it in the harder rock in the pit so we’re not really in a position yet to make direct comparisons with the DM45 rigs.” The Pit Viper is powerful and can drill a 12 m hole in one pass,” 136

Good teamwork: The Pit Viper PV-235 above was delivered in mid-2011 and working together with two DM45 rigs, it helped to complete 650 000 drillmeters in 11 months. Insert: Serkan Yüksel, Mine Manager at Tuprag, confirms that the mine aims to double production.

says operator Yasar Senturk. “You can also move the rig from setup to setup without lowering the mast which is a big advantage. That means you can drill an extra five holes each shift.” Both ore and waste are drilled on a diamond pattern, with a 4.5-5.25 m burden and slightly larger spacing. 152 mm holes with a COP 54 Gold hammer or 165 mm blastholes with the COP 64 Gold hammer cover the depth of a 10 m bench, with typically 800 mm of subdrilling. However, the blasthole rigs are not the only Atlas Copco rigs that have helped make Kisladag successful. The mine also runs a ROC L6 (renamed FlexiROC D50), equipped with a QLX 35 hammer primarily for presplit holes

for wall control. The rig drills 20 m double bench holes with a diameter of 95 mm and 1 m of sub-drilling. The layout involves a spacing of 1 m per hole around the entire pit periphery, requiring very accurate rig set up to achieve parallel drilling. “Another challenge is that the pit slope varies from 65 to 77 degrees, depending on the geotechnical sector from area to area,” Yüksel explains, “and we have experimented in the past with both single and double plane inclined holes.”

Acknowledgements The article on this page first appeared In Mining & Construction, No 2 2012 Blasthole drilling in open pit mining

UKRAINE, KOMSOMOLSK

Advanced iron ore mining in Ukraine Profitable pellets Poltava GOK (PGOK) is one of the most technically advanced iron ore mines in Ukraine and arguably one of the most progressive of its kind in the world. The turning point in the history of PGOK came when the new management made two key decisions: to concentrate solely on the production of pellets, and to invest only in the most modern mining equipment available. The PGOK fleet currently includes eight Pit Viper 275 blasthole drills. These are rotary and DTH rigs covering the hole diameter range 171-270 mm (6 ¾"–10 5⁄8").

Solid position The open pit iron ore mine near the town of Komsomolsk in central Ukraine is one of 10 deposits located on a single 5 km long magnetic anomaly strike. Owned by Poltava GOK, it dates back to the former Soviet Union when efficiency was not its first priority. However, following Ukraine’s independence in 1992, and subsequent privatization, everything changed and today the ore dressing and processing facilities are almost unrecognizable. PGOK, which is owned by Ferrexpo plc, is a modern, well equipped and highly developed operation which, with annual exports of some 10 million tonnes of iron ore pellets, ranks among the world’s top pellet suppliers. The turning point in the history of PGOK came when the new management made two key decisions: firstly, to concentrate solely on the production of pellets, and secondly, to invest only in the most modern mining equipment available. And it is the combination of these two goals that has driven the mine to success and given it a solid position among international iron ore producers.

The diesel-powered PV-275 is drilling 251 mm holes. In rotary drilling with tricone bits, high pressure air (24 bar) is used to clean the holes.

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Advanced iron ore mining in Ukraine

The PGOK benches are 10 to 12 m high and the drill pattern is 6 x 6 m in waste and 5.5 x 5.5 m in ore.

Modern drilling The iron ore at the PGOK deposit is extracted from medium hard rock and to drill the required 251 mm blastholes, the mine specialists chose the Atlas Copco Pit Viper 275, a top-of-the-line rotary drill featuring the computerized Atlas Copco Rig Control System. Voldymyr Chasnyk, parts and service manager at Atlas Copco Ukraine has this to say: “There’s no doubt that PGOK is one of the most modern enterprises in Ukraine. The company is the industry leader with modern equipment and has a determination to keep up with all new technical developments. “PGOK made up its mind to focus on iron ore pellets – in contrast to the other mines in the country which have a lot ofdifferent products – and they recognized the superior performance of the Pit Viper to help them achieve their goals.”

Steady progress By studying the productivity report, it is easy to see why the Pit Viper is the rig of choice here. Since it was first 138

introduced into the fleet in April 2006, productivity and output have both steadily increased whereas the number of rigs needed in the fleet to achieve the desired results has successively declined. Currently PGOK is operating a fleet of 23 drill rigs, eight of them Pit Viper 275. In 2010 there were 19 rigs in the pit and the total number of meters drilled was 780 000 (13% of which was done using three Pit Viper rigs, 17% with three TEREX rigs and 70 % by 13 SBSh (Russian made) rigs. For 10 months of drilling in 2011, the total number of meters drilled was 920 000, of which half was drilled using the eight Pit Vipers, 8% by TEREX and 42% using SBSh rigs.

Major shift PGOK has facilities for crushing, concentrating and pelletizing facilities on site and benefits from its sea port JV on the Black Sea, at Yuzhnye, near Odessa, from where it ships pellets to overseas markets. Voldymyr Ivanov, First Deputy Chairman of OJSC (Poltava GOK),

confirms that making the shift from the traditional fleet to the more modern Pit Viper has been a major undertaking. “Efficiency is productivity and because our focus is to be more efficient we are evaluating every type of equipment. That includes trucks, shovels, loaders, drills, transport systems – everything. “Our fleet plan has been developed in close cooperation with Atlas Copco Ukraine. Once our fleet includes more Pit Viper drills we will get even more efficiency as maintenance and repairs will be carried out by the specialized Atlas Copco Ukraine service company and this will allow for a considerable increase in equipment availability and drilling volumes.”

Mobility and flexibility Although the increase in productivity can, to a certain extent, be attributed to the advanced functions and efficiency of the Pit Viper, mobility played a decisive role in the choice. The mine’s previous fleet was electric but the PV is diesel powered, which meant that the rigs could move around freely from site to site without the restraints of power Blasthole Drilling in Open Pit Mining

Advanced iron ore mining in Ukraine

cables. Ivanov confirms that this mobility has been one major productivity driver. Another is the rig’s “live tower” capability which allows the rig to be moved with the rotary head at the top of the tower and rods loaded – an operation that was not possible with the older fleet. The benches are 10 or 12 m high and the drill pattern is 6 x 6 m in waste and 5.5 x 5.5 m in ore. In rotary drilling with tricone bits, high pressure air (24 bar) is used to clean the holes. The reason, explains Aleksandr Protsenko, is that this extends the life of the consumables. All of the Atlas Copco equipment is well taken care of under the terms of a full service agreement.Driller Victor Voznuk, who has more than three years of experience operating the PV-275, says he can drill a 16 m hole in about 15 minutes, which in these conditions is considered to be a good performance. He says he likes the Pit Viper for its safety features with “fewer opportunities to break things.” He adds: “The drills are more comfortable and have a better way of reporting drilling statistics and tracking productivity.” PGOK exploits the Gorishne Plavninskoye and Lavrikovskoye ore deposit which is some 8 km long, 2.5 km wide and 350 m deep, with a gradual dip ranging from 20 to 37 degrees.

Yeristovsky next in line Next in line is Yeristovsky GOK (YGOK) which is already under development. Prestrip operations have commenced with hard rock mining expected to start in early 2013. The deposit has an expected life span of approximately 32 years under the current development plan. It will produce on average 28 Mt of iron ore and 10 Mt of pellets or concentrate equivalent per year. In total, approximately 1 600 Mt of waste rock is expected to be removed and 800 Mt of ore to be produced, giving a favorable strip ratio of approximately 2:1. Ferrexpo has engaged international mining experts to assist in developing the operation to an international level. Bob Garrick, an Australian with many years’ experience in the mining industry, says: “We have been given

Top picture: The Pit Viper 275 is designed for multi-pass drilling down to 59 m and can be used for angle drilling with 0 - 30 degrees in 5 degree increments. Above: Driller Victor Voznuk enjojs the comfortable and ergonomic PV-275 cab.

a blank sheet to design the operation from the very start, without the constraints of having to modify an existing operation. As a result, we are able to take advantage of the latest technology available within the industry worldwide. “We are leading the Ukrainian mining indust r y with respect to equipment selection, being the first to introduce some of the largest trucks, excavators, rubber tired wheel dozers and graders. With respect to our selection for drilling rigs, it was obvious to us that the Pit Viper options were an ideal solution”. Garrick adds: “We value equipment reliability, life cycle costing as well

as in-depth preventative maintenance programs and product support – all of which Atlas Copco provide. Therefore we are happy with our decision to use the Pit Viper product.” YGOK intends to demonstrate to the industry that it is capable of developing a world class operation. With support from Atlas Copco and the Pit Viper drills this aim will soon become a reality.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 1. 2012

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Advanced iron ore mining in Ukraine

140

Blasthole Drilling in Open Pit Mining

Russia, Kovdor, murmansk oblast

Steep wall open pit mining at Zhelezny

The Zhelezny open pit mine at Kovdor operates Atlas Copco and Russian drill rigs, Russian electric shovels and Belaz, Caterpillar and Komatsu haul trucks. The in-pit crushing station is on the upper right of the picture.

Super-deep mining Kovdorsky GOK, one of two mining companies in the Kola Peninsula supplying two of Russia’s major phosphate fertilizer manufacturers, has decided to utilize superdeep mining at the Zhelezny open pit until reserves are exhausted in 2049. The technique relies heavily on precision drilling with equipment supplied by Atlas Copco.

Treasure Trove Discovered in 1933, the ore deposit at Kovdor in Russia’s Murmansk Oblast (67° 33’ N, 30° 30’E) is unusual, probably unique. The discrete, deep and more or less downwardly conical carbonatite deposit hosts 45 recorded minerals and is the type locality for five of these. It is also one of the Kola Peninsula’s two major sources of Apatite for fertilizer production, one of the world’s

few reserves of Baddeleyite (containing zirconia), and a substantial supplier of Magnetite. The mining method developed for the Zhelezny open pit is a bit special too. Described as a breakthrough technique in Russia, super-deep mining requires extraordinary control of drilling and blasting on near vertical benches. Kovdorsky GOK, which is part of the Eurochem fertilizer group, wants to minimize ore dilution while maintaining production rates – although bench areas will decrease as the mine deepens. The rim of the pit is approximately 200 meters (m) above sea level and is 2.3 kilometers (km) in length, 1.7 km wide and presently 170 m deep. Whereas mining was scheduled to cease in 2015 Kovdorsky GOK now intends to mine down to 660 m below sea level, thereby accessing an additional 330400 million tonnes of ore and enabling Zhelezny to produce 23 million tonnes

per year (Mt/y) until 2032. Output will then decline until closure around 2049.

Evolution The mining and processing operations at Kovdor started in 1959-62, initially recovering only the magnetite from 6 Mt/y of ore, explained Igor MelikGaikazov and Mikhail B Togunov, respectively Technical Director and Chief Mining Expert at Kovdorsky GOK. Super-deep mining is not the operation’s first technical breakthrough, they pointed out. During the 1970s the staff developed a process for separating the apatite and baddeleyite as well as the magnetite, with optimal processing achieved early in the 1980s. The iron ore is extracted by magnetic separation, then the pulp undergoes flotation to recover the apatite and, finally, gravity techniques separate the baddeleyite. In the same period the mineable area

Blasthole Drilling in Open Pit Mining 141

Steep Wall Open Pit Mining at Zhelezny

2.5 4.0

4.0

5.0

5.0

5.0 (m)

15 m

238 m

B

B

C

C

C

A = Pre-splitting holes B = Buffer holes C = Production holes

Sea level

15 m

A

A typical drilling pattern for drilling and blasting the Zhelezny benches.

660 m

*The Kovdor property also includes deposits of apatite-shtaffelite (AShR) and apatite-calcite ores. During the period 2000 – 2006 engineers developed an AShR open pit mining plan with 12 m high benches. The apatite-calcite part of the deposit below the AShR is regarded as a long-term strategic phosphate reserve.

Length 2.3 km

The Zhelezny open pit is 2.3 km long, 1.7 km wide and its current depth is approximately 170 m. The diagram shows the vertical orebody and the planned angle of the slopes at the projected depth of 900 m (dotted line). Kordovsky GOK aims to accomplish this with no significant expansion of the pit rim.

was extended by draining part of Lake Kovdoro and diverting the High Kovdora River to access all of the primary orebody. The pit has since been progressively deepened, with necessary changes to the material transportation systems and equipment fleet. Particularly interesting are the Cyclical Line Technology (CPT) in-pit crushing and conveyor systems used to haul ore and waste. Privatization in the early 1990s – as Kovdorsky Gorno-obogatitelnyi Kombinat (Kovdorsky Mining and Processing Combine, Kovdorsky GOK) – was followed by a difficult period. But in 1998 management started exploiting baddeleyite-apatite-containing waste from magnetite-only processing stored in sedimentation ponds*. This enabled Kovdorsky GOK to compensate reductions in mine apatite and baddeleyite output made in response to low iron ore demand until 2005. In 2001 EuroChem Mining and Chemical Company JSC (EuroChem), reputedly Russia’s largest integrated fertilizer producer, acquired the Kovdor facilities. A report for Kovdor’s 40th anniversary in 2002 commented 142

that 1997-2001 had been a period of stabilization for the operation and for Kovdor city. During 2003 the Kovdorsky team introduced (and later modified) a Strategic Development Programme suited to EuroChem’s phosphate feedstock requirements that covered the period until 2015. Commenting on progress in the period 2003 – 2006, senior personnel1 pointed out that the mine succeeded in restoring ore production to the desired long-term 16 Mt/y target. The planned apatite concentrate recovery from open pit ore in 2010 would be about twice the amount achieved in 2001.

Super-deep mine planning The mining licence for Kovdor allows mineral extraction from the primary orebody to a depth of two kilometer and a major mine redesign to exploit the lower levels started early this century. The start of super-deep mining was preceded by several years of advanced and extensive studies using some of the most sophisticated methods of testing, calculation and data processing in the

industry. In view of general trends and advances in rock mechanics Kovdorsky GOK decided to continue development of the Zhelezny pit to lower levels rather than switch to underground mining. To avoid widening the surface pit rim and creating large volumes of waste rock the project team focused on super-deep mining of benches with vertical or near vertical highwalls. Initial geomechanical studies enabled expert organizations to produce parameters for the engineering geologists and a 3D geological-structural map of the Kovdor deposit for use in forecasting potential slope failures. Five engineering-geological sectors of the pit were defined and for each one the bench slope angles, bench heights and widths of safety berms were calculated. This information was used to develop specifications for super-deep excavation using methods such as presplit drilling and blasting. These specifications are used in conjunction with techniques for the relief of water pressure in the benches; stabilization of weak rock masses by, for instance, rock bolting and cement mortar injection; and thorough slope stability monitoring for which Kovdorsky is using three methods: visual observation, surveying with electronic and optical instruments Blasthole Drilling in Open Pit Mining

Steep Wall Open Pit Mining at Zhelezny

including laser scanning, and seismic monitoring in high risk areas. Once the deep mining concept was approved by EuroChem, the Giproruda institute started work on the mine redevelopment plan in 2004 and two years later completed the project – “Reconstruction of the open cut for restoration of the project capacity of Kovdorsky GOK by means of the use of steeper constant open-pit benching and in-crease of the open pit depth and duration of open-pit mining”. Two pit design versions were used for technoeconomic evaluation. Stage One of forward development will hold open pit output at 15-16 Mt/y of baddeleyiteapatite-magnetite ore and 7 Mt/y of low-iron apatite ore until 2032, thereafter production will decrease gradually until closure.

Drill and blast design Blasting at Zhelezny was thoroughly modernized from the late 1990s to 2005. The mine introduced non-electric initiation with Nonel and Primadet systems and from 2000 progressively switched to EVV emulsion explosives – VET emulites. Consequently, in 2006 as compared with 2001 (figures in brackets), 99.1% of blasting was with EVV, using 21,500 t (9,400 t) of explosive, and yielded 15.25 Mm3 (7.5 Mm3) of blasted rock; 200t (2,400t) of conventional explosives blasted 0.23 Mm3 (2.59 Mm3) of rock. VET explosive is mixed by the Russian company Eastern Mining Services Ltd, a subsidiary of Maxam, delivered to the holes and charged using SZM mixing-charging machines. The new technology significantly reduced the number of misfires. The super-deep mining system required further improvements to blasting practice. Firstly, it was essential to reduce fragment size as even sizeable increases in the amount of explosive used in the 250 mm production blast holes did not fragment the rock to dimensions sufficiently small to improve performance of the CPT systems, truck haulage, or comminution. Secondly, the drill-blast system used in the zones near the pit rim must maintain the stability of the benches and steep highwalls and not disturb the rock mass outside

Contractor Technobur has four Atlas Copco Drilling Solutions DML rigs working for Kovdorsky GOK. Three are low pressure (LP) rigs for rotary drilling, and one is a high pressure (HP) rig for DTH drilling or rotary drilling.

the mine walls. Thirdly, because the proportion of wet blast holes is expected to increase, waterproof explosives would be required. Blastability studies led to the definition of five categories and for each one the burden, hole distance and height of explosive charge are calculated in relation to hole diameters, bench height, grade of emulsion charge and row position in the blasting sequence (see illustration page 110). Typically, the inner blocks of the bench are drilled with smaller diameter bits, transitional blocks are drilled with the smaller holes on the inner part but with larger holes further away, and outer production blocks are entirely drilled with the larger diameter holes. Using emulsion explosives reduces impact on the environment, especially the urban area close to the mine as they emit less gas and dust pollutants and the vibration effects are easier

to control. For routine planning mine surveyors and drill-blast engineers use the GIS GEOMIX information system developed by Kovdorsky and the VIOGEM FSUE organization and introduced in 2004. They report that this has improved blast preparation and stabilized the quality of ore feed to the process plant. System development continues.

Upgrading the drilling fleet For more than 30 years Zhelezny relied on Russian-built electric powered rotary drilling rigs to drill 250 mm and 270 mm diameter holes. But, as Mikhail Togunov pointed out, a fleet able to drill a wider range of hole diameters with optimum efficiency would be crucial for super-deep mining. Accordingly, in 2004 Kovdorsky GOK acquired one imported rig for

Blasthole Drilling in Open Pit Mining 143

Steep Wall Open Pit Mining at Zhelezny

A major player in Kovdovsky’s Super Deep Mining programme: Atlas Copco’ s DM45 HP (high pressure) rig on the pit’s upper, 12 m high benches.

drilling 171.4 mm diameter holes. Two Atlas Copco ROC L8 down hole drilling (DTH) rigs were added in 2005 in order to drill 140 mm pre-split holes and also 165 mm buffer hole rows close to the margin of the benches. The new rigs demonstrated the advantages of using smaller holes that match the physico-mechanical properties of the rock. These results and the bench configurations required for super-deep mining persuaded Kovdorsky GOK to use diesel-powered as well as electric drilling. The diesel rigs could drill the required smaller hole sizes and also work efficiently where long tramming distances are a disadvantage for rigs with power 144

cables. Nevertheless, the old electric rigs achieve high performance indices and Rig Numbers 15 and 16 have respectively completed 500 and 600 drill km since they went into operation. So Kovdorsky GOK has retained five SBSh electric rotary rigs plus the two ROC L8 and one other DTH machines. Management also looked for an external drilling partner. These efforts led to the deployment, starting in 2007, of a second drilling fleet comprising Atlas Copco large blasthole rigs operated by a Russian contractor, Technobur. This company, based in Moscow, was formed in October 2004 by an experienced team specifically to carry out mine drilling. Prior

to the contract at Zhelezny, Technobur had started work at Olcon’s Olenogorsk iron ore mine north of Kovdor and has a Pit Viper 275 there. The company also tested a DM 45 against SBSh rigs at Olenogorsk, finding the diesel machine was 30% faster. Presently Technobur operates an Atlas Copco fleet at Kovdor comprising three DML LP rigs (1600 and 1200), one Pit Viper 275 LP, one DML HP 1250 and two DM 45 HP machines. This fleet usually does more than 70% of the meters drilled at the mine, over 40,000 m of a total of 55,000 m in a month being typical. All the rigs are set up for multi-pass drilling. To a depth of 70 m above sea level benches are 12m high but below this level they are generally 15 m high with 3 m sub-drill. Production holes are normally 14-20 m in depth. Presently the slope angles range 35-40° from vertical but the long term aim is to make them as near vertical as possible. The rotary rigs use Russian tricone bits while the down hole production drilling is done with Atlas Copco Secoroc COP64 hammers and 165 or 200 mm bits. The DML and DM 45 high pressure rigs can be used either for down hole drilling or for rotary, in which case the pressure and engine power are reduced. They are fitted with inclination angle indicators for use when tramming. Technobur services the rigs with help from Atlas Copco, explained the company’s site manager Evgeny Perevozchikov. The project has been progressing according to plan and Kovdorsky GOK expects to reach its first stage targets in 2011. Reference

1. D S Strezhnev, N A Ganza, I V MelikGaikazov, A P Ivakin, N N Mel’nikov, N V Cherevko: Kovdorsky Mining-andProcessing Integrated Works Builds the Future: Realization of Strategic Program of Long-term Collaboration. Eurasian Mining – Gornyi Zhurnal 1, 2008.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 1 2010. Kyran Casteel of Mineral Industry Intelligence & Information visited the mine in 2009. Blasthole Drilling in Open Pit Mining

MONGOLIA, GOBI DESERT

Mining industry’s new beginnings in Mongolia Mongolia may become the new ‘Saudi Arabia of Coal’ Mongolia’s newly discovered metal and energy resources position it to become a world mining leader. The aggressive development strategy and rapid growth of SouthGobi Sands make that company a trailblazer within Mongolia’s coal industry. Part of the strategy at SGS’s Ovoot Togoi mine has been working with Atlas Copco to put together a drill program that will conquer many of its challenges with its Pit Viper 275 and DM45 blasthole rigs. SouthGobi Sands’ Ovoot Tolgoi mine has two pits in development: Sunset and Sunrise.

Generally held to be the world’s most sparsely populated nation, in 2011 Mongolia became the number one coal importer to one of the world’s most populous nations, China. To date China has been able to supply most of its energy needs itself.However, in 2009 China passed the United States to become the world’s largest energy consumer. The International Energy Agency has forecast that China’s overall energy needs will increase 75 percent by the year 2035 and demand for coal, since China has insufficient natural gas and oil resources, is rapidly increasing. In addition to its increasing consumption of coal, China’s future need to import foreign coal will grow even greater as its own coal production dwindles. China is believed to have only about 20 to 30 years’ worth of its own mineable coke to support its thriving steel industry. Mongolia is positioned better than any other nation to meet China’s need. The county’s coking coal resources hold more than enough coal to meet

China’s needs, as the Tavan Tolgoi region of the Gobi Desert in south central Mongolia’s holds one of the world’s largest deposits of high-grade coking coal. Industry pundits have suggested Mongolia may be on its way to becoming the new “Saudi Arabia of Coal,” a title generally used in the past to describe the United States. While others scurried in response to Mongolia’s sudden importance in the coal industry, Mongolia’s SouthGobi Sands (SGS) was already at work at its Ovoot Tolgoi mine in the Gobi desert setting high standards for others to follow. Going into 2012 it owned three projects already, with exploration licenses for 12 more, all of them wholly owned by SGS.

Ovoot Tolgoi Ovoot Tolgoi was the first of SGS’s three coal projects to go into commercial production. Mining in the Ovoot Kuhral

Basin, the mine is located only 40 kilometers from the China border, ideally situated for its primary client. SouthGobi Sands’ Ovoot Tolgoi mine has two pits in development: Sunset and Sunrise. The older and larger of the two is the Sunset pit with Sunrise just taking shape. Licenses were issued in 2007 when Sunset produced 1 million tonnes. In 2011 the mine produced 4.5 million tonnes and confidently set a goal of 8 million tonnes for the following year. In December 2011 the mine upgraded its resource data, having determined a proven reserve of 62.8 million tonnes of high-volatile B and A bituminous coals. According to the ASTM D388 standard, high-volatile B coal yields 7,212 to 7,785 kilocalorie-per-kilogram (kCal/kg). The heat output of highvolatile is more than 7,785 kCal/kg. Another 44 million tonnes of probable resource brings total resources to 106.8 million tonnes. SGS actually

Blasthole Drilling in Open Pit Mining 145

SOUTH GOBI SANDS

Even though the mine is in the Gobi Desert, the mine had to deal with the challenge of ground water. Ground water often freezes in this climate, so the mine uses a dewatering unit and switched to a bulk-based explosive program.

produces two other coal products in addition to hard and semi-soft coking, or metallurgical, coal. These screened medium ash and screened high ash/ sulfur coals are upgraded to semi-soft coking coal through a dry-air separation and washing. At Olvoot Tolgoi the company can remove waste rock and blend different kinds of coal taken from various seams with its on-site dry coal-handling facility. It is capable of processing 9 million tonnes of coal per year to create highervalue products.

High production equipment The mine started out with three Atlas Copco DM45 blasthole drill rigs for surface work and, for larger production holes, uses the Atlas Copco Pit Viper 275 blasthole rigs. To meet its production goals the mine added two PV-275 drill rigs to the four it already had. This plan matches the Ovoot Tolgoi growth in digging and hauling equipment. The big excavator for the mine is Liebherr’s 996 with its 34-cubic-yard bucket and the Liebherr 9250 with 17-cubic-yard capacity. The mine uses 146

the Terrex MT 440PC 240-ton haul truck. It will be adding a second 996 excavator to its fleet this year and will increase its truck fleet from 12 to 22.

Unique difficulties in drilling Acting Mine Manager John Howlett said Ovoot Tolgoi is like any mine with the exception of what he calls “some really crazy seams.” The largest of the seams that run through both pits is Number 5. It is about 50 meters thick near the surface, but dips at a 45-degree angle. There are multiple seams lying side by side. Exploration drilling has found seam Number 5 at a depth of 800 meters. The Ovoot Tolgoi surface mine based its plans on a 20-year mine life, mining to a depth of 300 meters, but this could increase as coal demands rise. Future plans tentatively include going underground. Ovoot Tolgoi General Manager Rodney Lacy said to date they have moved 8 million tonnes of coal to roughly 35 million total bank cubic meters (BCM) of overburden. Howlett

said his plan is to keep at least 1,000 holes drilled at all times. A single excavator can excavate 1,600 BCM an hour or 28,000 BCM total a shift. SGS wants to keep 800,000 BCM ready for the shovels at all times. Mining coal in Mongolia is a challenge. With the extreme temperatures and complex geological formations, Mongolia challenges even the most experienced engineers and miners. Other challenges to the drilling operations are the sharp folding of the coal seams and the steeply dipping footwall. Drilling and blasting practices have been modified to allow for a stable final pit wall. SGS found what Lacy called conglomerates at the bottom of the pit. These areas were tougher to drill and blast and required patterns to be tightened for better fragmentation. This is another reason for the transition from the DM45 to the larger, more powerful PV-275. The drill’s greater pull down force penetrated the conglomerate mass with ease. The standard burden and spacing was 5.4 by 6.2 meters for the DM45 with a 7 ¾-inch hole and 8 by 9 meters Blasthole Drilling in Open Pit Mining

SOUTH GOBI SANDS

The mine added 200 employees in 2011 with miners being bussed from three local communities up to 130 km away.

for the PV-275 with a 9 7/8 -inch hole. The bench depth was 12 meters with 1 meter of sub-drill where needed. The PV-275 allowed double benching to help develop the wall in unstable areas. One unexpected problem they encountered was ground water. Even though the Gobi Desert shows very little vegetation and annual precipitation, the mine has encountered a fair amount of ground water. Because the temperature is below freezing, wet holes freeze over. To remedy the situation the mine included a dewatering unit and began a transition from package explosives to a bulk-based program, bringing about significant cost reductions and greater flexibility.

and Noyon soum are 100 kilometers and 130 kilometers away from Ovoot Tolgoi, respectively. Additional employees and a few ex-patriots in lead positions were flown in from the country’s capital, Ulaanbaatar, nearly 1,000 kilometers away. In early 2012 the company had nearly 600 employees, with 75 to 80 percent of the drillers

coming from the local communities. Because of its proximity to the communities, the mine donates 2,000 tonnes of coal annually to them. Having a fairly new work force also required an intensive training program. Lacy thinks the Mongolians are an independent-natured people, requiring a team approach to training as it relates

Developing the mine The mine has put together an equipment and personnel plan that will keep it on track. In 2011 alone added 200 employees to the Ovoot Tolgoi operation. Miners were being bussed from three of the local communities. The Gurvantes soum of Umnugobi district is the closest to Ovoot Tolgoi, just 30 kilometers away. Sivrie soum

The largest of the seams that run through both pits is Number 5. It is about 50 meters thick near the surface, but dips at a 45-degree angle. There are multiple seams lying side by side. Exploration drilling has found seam Number 5 at a depth of 800 meters.

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SOUTH GOBI SANDS

to safety. From the start, each miner has to learn the basics, from radio instruction to team work. Communication is a key part of the training program from the top down. Lacy said it starts with a new-hire meeting they have every Wednesday. Part of that meeting is devoted to sharing about each other’s history and family and offering the new hire a chance to do the same, said Lacy. He believed this builds a unity and camaraderie that promotes safety.

Where does it lead? SouthGobi Sands is more than a coal exporter. In addition to the 600 to 700, 100-tonne trucks that roll the 45 kilometers to the China border every day, the mine is looking to the future. In the beginning those trucks were running on a dirt road, and the journey took nearly three hours. In keeping with its progressive philosophy, the mine immediately began building a four-lane road to offer better transport to every mine in the area. That includes the company’s next property, Soumber Mine, which will open up in the coming years. Developing a mine is not enough for SGS. Management knows Mongolia’s future is mining and that, as it builds Ovoot Tolgoi, it is building the foundation of the industry in Mongolia. The foundation comes in the form of small business loans to companies wanting to start up mine service and support operations as well as from development of tomorrow’s miners through technical school associations and engineering programs. The mine’s engineering team is an example of the company’s success. Lacy thinks the team is top notch and is growing their skills. This will not only support the needs of the mine but also the development of the country for years to come.

The DM45 is used for drilling 7 ¾ inch holes in a 5.4 x 6.2 m drill pattern.

Acknowledgements Article and photography by Scott Ellenbecker General Manager of Ovoot Tolgoi Operations Rodney Lacy.

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Blasthole Drilling in Open Pit Mining

Australia, new south wales & queensland

Coal mining in eastern Australia Hunter Valley Shipping 260 million tonnes in 2008, Australia is the world’s largest exporter of black coal. Roughly one third comes from coalfields in New South Wales, two thirds from those in Queensland. Pit Viper 275 rigs are contributing to production from the Hunter Valley in New South Wales and the Bowen Basin in Queensland.

Multi-seam, multi-pit mining Coal production and export is a very serious business in the Hunter Valley, New South Wales. Normally one train passes through Muswellbrook carrying coals to Newcastle, Australia’s major coal shipping port in 2008, every 20 minutes, said Robert (Rob) Swan. Muswellbrook (pronounced Musselbrook) lies pretty central to the main Hunter Valley coal mines; it is where the Atlas Copco office and service facilities for the area are located and where Rob, who is the Regional Manager – Eastern New South Wales, is based. It is also quite close to the Hunter Valley Operations (HVO) “which has proved very convenient for us”, said Dale Radnidge, the HVO Maintenance Supervisor, whom we met at an office complex known as Cheshunt Bathhouse located in the southern section of the HVO. Located 24 km northwest of Singleton, the Hunter Valley Operations, are 100% owned by Coal & Allied Industries Ltd, which in turn is managed by Rio Tinto Coal Australia. Rio Tinto describes the Operations as a multiseam, multi-pit open cut mining operation. HVO comprizes: part of the Howick mine, now known as the West Pit, which started operating in 1968; the Hunter Valley No. 1 mine, where production began in 1979, and the Lemington mine, which commenced coaling in 1971. Coal & Allied merged the Howick and Hunter Valley mines in 2000 to create Hunter Valley Operations

In the Hunter Valley, New South Wales, Coal and Allied Industries mines a multi-seam, multi-pit operation.

and included Lemington when it was acquired in 2001. The company will approximately produce between 10.5 and 13.5 Mt/y. In addition to the Hunter Valley Operations, the Coal & Allied portfolio includes the quite new Bengalla strip mine 4 km west of Muswellbrook and the integrated Mount Thorley Warkworth open cut mines 15 km southwest of Singleton.

Purchase factors Dale Radnidge explained that there had been various reasons why Coal & Allied (C&A) wanted to buy the Pit Viper 275. For one thing, it would be fitted with the Cummins QSK 19 Tier 2 compliant engine that will meet the relevant Australian environmental impact regulations for some time to come. C&A had good previous experience with the Pit Viper’s predecessor rig, the DM-M2, which was bought in 1995. This has always been a very cost effective machine for the company, with very good life cycle costs – despite the fact that the rig has had to operate for periods in

ambient temperatures of over 50° C. Dale had also had positive feedback from Pit Viper owners concerning the steps taken by Atlas Copco Drilling Solutions to improve features that had been weak points on the older rigs. At the crunch, Atlas Copco quoted a competitive purchase price and the component life cycle costs were acceptable. Atlas Copco also offered to provide a maintenance technician for 12 months: previously an Ingersoll-Rand Drilling Solutions rig owner himself, this technician has also helped the Atlas Copco team at Muswellbrook to identify maintenance issues.

Regulatory issues However, life is not too simple for equipment purchasers in Australia, especially in New South Wales where the government guidelines on equipment specifications, primarily designed for machinery operating in coal mines, are the most stringent in Australia. Rio Tinto Coal Australia management also has very strict rules covering equipment specifications and it was necessary to

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Coal mining in eastern Australia

workshop. They could therefore make recommendations as to the changes to be made in addition to those modifications necessary for regulatory reasons. These additional alterations were intended to make it easier to maintain the PV-275. Meeting NSW electrical equipment requirements necessitated taking out the whole electrical system and installing a different one. Some of the hydraulic system components also had to be changed.

Operation

HVO Maintenance Supervisor Dale Radnidge (right) with Atlas Copco’s Rob Swan.

have the standard version of the PV-275 modified in a number of respects. Dale Radnidge, the maintenance electrician and maintenance fitters at HVO were involved and so was the unit’s production trainer. The order was placed late in 2007, not too long after the AIMEX mining equipment show in Sydney, and Atlas Copco was able to deliver the PV-275 that had been displayed - in yellow and gray livery – to the Muswellbrook workshop. C&A also ordered a new Atlas Copco DML rig that required rather more modification than the Pit Viper. Mr

Radnidge explained that a major aim of purchasing these two rigs was to start to create a unified fleet of different size drills with a common cabin design so that each operator can easily switch from one model to another when necessary. The DML rig has replaced an existing competitor machine, whilst another elderly competitor machine had been put on stand-by when the PV-275 started work.

Modifications The HVO maintenance team were able to inspect the Pit Viper at the Atlas Copco

The Coal and Allied Ltd Pit Viper 275 is fitted with a Cummins QSK 19 Tier 2 compliant engine.

150

The mines presently use a walk meter and laser depth indicator in conjunction with mine survey data for drill positioning as the hardware needed to use the GPS system on the PV-275 is not in place yet. The DML has the Aquila system fitted for use with HVO’s Modular Mining Dispatch f leet management system. Dispatch is also being used to monitor the availabilities being achieved by the two new Atlas Copco drilling rigs. At the time of the visit, the Pit Viper was being used with five rods to drill 54 m holes in overburden for blasting and stripping by either dragline or shovel. However, the drilling requirements range from 10 – 60 m depth although the bulk of the benches are drilled with 30 – 40 m vertical holes. Hole size is 7⅞ in for coal and partings and 10⅝ in for overburden. Pre-split holes are drilled at either 10 m or 80 m spacing, in both cases at a 15° angle. Approximately 20 – 25% of drilling time is spent on the pre-splits. All nine drilling rigs working at HVO use Secoroc tools provided through a separate supply and service contract that has been in force for six years. HVO has two Bucyrus International draglines (1 x 1370, 1 x 1570), six P&H electric shovels and a Terex-O&K RH70 hydraulic excavator. As well as the Atlas Copco drilling rigs there are six older ones from other manufacturers. Mr Radnidge explained that this mixed fleet was built up as a result of the merging of the mines that are now part of the Hunter Valley Operations. C&A has been using the maintenance planning tools in the SAP software portfolio since May 2008. Blasthole Drilling in Open Pit Mining

Coal mining in eastern Australia

C&A intends to create a fleet of different size drills with a common cab design so that each operator can switch easily from one model to another.

Summarizing, Dale Radnidge said that not only was the deal which Atlas Copco offered sound but the working relationship that C&A has established with the Atlas Copco team has been good too. C&A is comfortable with the purchase. Indeed, HVO had planned to buy two more rigs, which had been shipped to Australia. However, in the current economic climate this will not be possible during 2009.

Queensland – Drillpro Services The vast Bowen Basin coal deposits in mid-Queensland extend from the area west of the coastal city of Bowen to south of the Tropic of Capricorn in an area which lies west of Gladstone. The mines are connected by rail lines to five major ship loading Coal Terminals: Abbott Point near Bowen, Hay Point and Dalrymple Bay near Mackay, and the RG Tanna and Barney Point terminals

near Gladstone. The Bowen Basin accounts for roughly half the world’s seaborne trade in metallurgical (coking) coal. Drillpro Services is a drill services and drilling contracting company formed by John Anderson, who had previously worked in a senior position for a major Australian equipment dealer handling machines competing with the Atlas Copco Drilling Solutions range. Having started out selling drill rig parts and doing rig rebuilds, Drillpro bought its first rig for contract drilling in 2001, followed by two more each year after that. For some time the company used the rigs John Anderson had previously sold, but later Drillpro experienced problems with a particular model so Mr Anderson decided to try the equivalent Pit Viper 275. He is now an enthusiastic customer and advocate. Currently the company has two Pit Vipers working at widely separated mines in the Bowen basin. The first to be delivered

The HVO Pit Viper was being used to drill 54 m holes in overburden, using five rods.

Hole sizes are 7 7/8 in for coal and partings, 10 5/8 in for overburden.

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Coal mining in eastern Australia

Drillpro Services deploys one of the company’s two PV-275 rigs at the Wesfarmers Curragh Pty Ltd Curragh North extension.

is at the Curragh operation between Blackwater and Emerald, one of several mines lying close to the Tropic, and the second about 300 km further north at the Coppabella mine.

Phil Smith finds the Curragh Pit Viper easy to use.

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Curragh North Operated by Wesfarmers Curragh Pty Ltd, which is wholly owned by Wesfarmers Ltd, the Curragh mine was first

developed by an ARCO-led consortium mainly to supply thermal grade coal to the Stanwell power station near Rockhampton in Queensland. Subsequently metallurgical coal production has grown and the company exports this grade together with surplus thermal coal. Target export tonnage for the Financial Year July 2008 – June 2009 was 7.0 Mt while 4.0 Mt would go to Stanwell. Production from the original Curragh mine has been supplemented by the development of the Curragh North extension. There are three draglines working at Curragh and two at the extension, where there are also hydraulic excavators loading Caterpillar trucks (793 and 789 models). Both types of coal are mined from this extension: one grade is taken to the coal preparation plant at the original mine by a belt conveyor, the other is hauled by large high-sided truck-trailer units. The plant also washes coal from Yarrabee, some 25 km to the north. Thiess has the overburden stripping contract at Curragh North, with Drillpro doing the drilling and other specialist firms, including Orica, carrying out the blasting. The overburden is mainly sand and gravel. John Anderson explained that Drillpro Services has worked at Curragh for 11 years. Under the current threeyear contract the company operates and maintains two drills that belong to the mining company as well as the one PV-275 and one DM-M3 that Drillpro owns itself. The Pit Viper is working at the Curragh North extension. From January 5 to January 18, 2009 Drillpro had drilled 51,000 meters, as compared to the mine’s target of 25,000 m/week. This requires a penetration rate of 850 m per 10 hours drilling per shift. However, Curragh was looking to increase the rate to 30,000 m/week. From early August 2008, when the PV-275 started work, up until the time of our visit on January 20, 2009, the rig had drilled 130,000 meters. The rig was still using the original drill rods and had thus far achieved 98% availability, Mr Anderson said. Both this Pit Viper and the one at Coppabella drill 270 mm holes. However, the Curragh machine has a Cummins QSK engine while the Coppabella PV-275 has the Cat C27 option. Blasthole Drilling in Open Pit Mining

Coal mining in eastern Australia

Usually Drillpro uses a DM-M3 for drilling 25° pre-split holes and 20° bench holes for cast blasting. Sometimes, commented John, Drillpro gets held up because the pre-split holes are not blasted soon enough. However, the area we visited had a soft wall so pre-split drilling was unnecessary. We watched Phil Smith operating the PV-275. He drilled the A/O hole to 51m and the holes H11 to A11 to between 47 and 50 m. Phil Smith has 17 years’ experience in exploration drilling followed by 3½ years of production blasthole work, including drilling with the DM45 and the Driltech D75 rigs. He told us that the PV-275 is better than both of them: it is easier to use and has more feel for the drilled rock. The cabin’s perforated blinds were very helpful in the bright Australian sun, eliminating glare but providing sufficient visibility for Phil to move the rig from one hole to the next drilling position. John Anderson remarked that he would like to have a window in the cabin roof to provide a view of the mast, but the design of the FOPS cab makes this impossible. Instead there is a camera system which the operators took some time to get used to, but now find perfectly satisfactory.

Modifications As in New South Wales, though to a slightly lesser extent, some modifications are essential to meet the Queensland government guidelines, explained Don Emery, who is Atlas Copco’s Regional Manager, Mackay. And although John Anderson could not have his roof window, he did get several substantial modifications that he asked for. The Curragh Pit Viper was shipped into Brisbane, trucked to the Mackay workshops where it was modified, trammed into the Queensland Mining Exhibition held from July 24-27, 2008 and then delivered straight to the mine site. In carrying out the alterations Atlas Copco was considerably assisted by an adjacent firm of boilermakers which could generate the required drawings and do some of the fabrication. In addition to rewiring according to Queensland standards, the main

The second Drillpro PV-275 works at the Coppabella & Moorvale JV’s Coppabella mine.

modifications and additions included: a modified walk-up ladder; one platform in front of the cabin and another to provide high level access to the

mast; a Hiab crane, with its own power supply mounted under the cabin, to help with drill tools handling; addition of a Chubb fire suppression system on

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Coal mining in eastern Australia

a rail around the engine; two lifting hooks; and a microwave and fridge. Several of the standard features were relocated for greater convenience, such as the isolators, which were moved to the back end of the frame to be within reach from ground level, the Wiggins fast fill unit and the lube drums. Phil Smith was particularly enthusiastic about the Hiab crane which makes his life a good deal easier, he said. The Coppabella machine was delivered with the lift hooks pre-fitted, an upgraded engine fire suppression system and greasing access for the driveline to the pump. In addition, extra tanks were fitted for dust suppression so that refilling is required after two shifts. As well as a Hiab crane and extra platforms like those on the Curragh Pit Viper, there is an access to the mast and the camera on the mast via the top of the cabin.

Coppabella The overall operation and the mining operation at Coppabella are managed by Macarthur Coal (C & M Management) Pty Ltd – working on behalf of the Coppabella and Moorvale Joint Venture. The Joint Venture comprizes Macarthur Coal Ltd (73.3 % stake held via Coppabella Coal Pty Ltd); CITIC (via CITIC Australia Coppabella Pty Ltd), Marubeni Corp. (via Mapella Pty Ltd), and Sojitz Corp. (via Winview Pty Ltd) each holding a 7 % interest; JFE Shoji Trade Corp. (3.7 % held via KC Resources Pty Ltd); and Nippon Steel Trading Co. Ltd – 2.0 % held via NS Coal Pty Ltd. The coal handling and preparation plant has a capacity in excess of 6 Mt/y raw coal and is operated by the Sedgman Coppabella Joint Venture. The mining lease was granted on June 1, 1998, overburden removal started in July 1998 and the first coal was mined in October 1998. By April 2007 Coppabella had yielded 40 Mt of run of mine coal. Macarthur Coal’s attributable production in 2008 was 2.57Mt. Proven and probable reserves totalled 67 Mt as at 30 June 2008. The operation is located adjacent to the Peak Downs Highway, 140 km southwest of Mackay between Nebo and Moranbah. It mainly produces a 9% ash, 154

Drillpro’s Pit Viper 275 rig at the Coppabella mine, seen here in the Johnson Pit South, is equipped with the Caterpillar C27 engine option. The machine drills 20° angled pre-split holes and either 20° or more often vertical main bench holes.

low volatile PCI grade metallurgical coal that is railed to the Dalrymple Bay Coal Terminal near Mackay. But, in response to market trends, Coppabella has revised its mine plan in order to mine thermal coal and reduce PCI grade output, demand for which has fallen sharply. This also meant that 140 people were laid off in mid-December 2008. John Anderson’s son Matt joined Drillpro Services in 2003 and now manages four contract sites in the area. Of these Coppabella, where Neal Torresan is the company’s site supervisor, is the largest but the other clients are prestigious – BHP Billiton Mitsubishi Alliance (BMA), whose Poitrel mine is operated by the contractor Leighton; Vale Australia’s Broadlea; and Peabody’s Eaglefield, where the main contractor is Macmahon. Drillpro was also bidding for work at BMA’s South Walker Creek mine, where Thiess is the mining contractor. At Coppabella, overburden removal is primarily by dragline, coal mining by large excavators loading trucks. Orica is responsible for blasting the holes Drillpro drills under the terms of an 18

month contract. There are presently three producing pits; East, Southern and Johnson. Drillpro has the PV-275 and one other rig operating, one spare machine and one parked unit, all of these being of other make. (When bidding for new contracts having idle machines can help, commented Matt Anderson.) The Coppabella PV-275 rig drills 20° angle, 18 meter pre-splits and 12-18 meter main bench holes, of which some are angled at 20° but most are vertical. The coal is 13-14 m thick in places at a depth of approximately 37 meters below surface. Jason Camielleri was operating the drill during our visit to the Johnson Pit South. Routine servicing of the Coppabella machine’s Cat C27 engine is done by Drillpro but any guarantee work is done by the Caterpillar dealer. At the time of our visit the machine had done about 1000 hours.

Acknowledgements Kyran Casteel, a Contributing Editor for Coal Age and Engineering & Mining Journal, visited the New South Wales and Queensland coalfields in January 2009. Blasthole Drilling in Open Pit Mining

Australia, brisbane, Queensland

The fuel cost killer of Queensland New technology improving drilling economy Mining contractor DDQ of Queensland, Australia has slashed fuel costs dramatically since adding a new Atlas Copco Pit Viper 235 rotary drill rig to its fleet. The secret is the Atlas Copco patentpending automatic clutch system. Also the new breakout system and the 12.2 m single-pass capacity make the rig a lot quicker and smoother to operate. DDQ has been operating at the New Acland coal mine for about four years and introduced the PV-235 there in February 2012.

Drilling contractor About 75,000 dollars in three months, 1,000 liters every 24 hours, and half a million dollars per year: these are the kind of fuel savings now being experi­ enced by Australian mining contractor Deveth Drilling Queensland (DDQ) after adding a new drill rig to its fleet. DDQ is benefiting from the first class economy of Atlas Copco’s Pit Viper 235 rotary rig, and is passing its sav­ ings on to its client, the New Hope Corporation and its New Acland coal mine. Nigel De Veth, owner and founder of DDQ, says: “In the first three months alone we’ve saved the mine 75,000 (AUD) in fuel, and that was through a trial period, really just phasing the machine into the work. The potential savings are over 1,000 liters every 24 hours so you’re looking in the vicinity of half a million dollars a year.” The low fuel consumption was a decisive factor behind the company’s decision to purchase the PV-235. De Veth adds: “We’re now getting about 50 to 55 liters an hour with this rig and the main contributor to that is the wet clutch technology on the compressor.”

The Pit Viper 235 was introduced to the New Acland coal mine in February, 2012.

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The fuel cost killer of Queensland

Nigel De Veth, owner of DDQ, is delighted with the fuel savings and other advantages of the Pit Viper 235.

Push-button economy The hydraulically operated patentpending automatic clutch is an out­ standing feature of this hydraulic tophead drive rig, which can be config­ ured to perform a range of rotary and DTH drilling operations. “With the PV-235 you don’t get air unless you ask for air, so if you want air for drilling, you press the button and the clutch engages and the compressor throws in. So the compressor is only ever used when you want it,” explains De Veth. He continues: “Atlas Copco has replaced all the rod greasers and air greasers, etc, with electric pumps so they are not reliant on air. There’s nothing on the machine that relies on air other than your drill bit.” DDQ has been operating at the New Acland coal mine for about four years and introduced the PV-235 there in February 2012, drilling mainly 229 mm blastholes to a depth of 50 m. 156

“The best that we’ve drilled so far is close to 1,200 meters in 10 hours and I think there’s much better to come yet,” says De Veth. “The guys have only just finished getting used to it and things are starting to happen. We’re probably looking at 10 meters an hour more with this machine.” Key to the efficient operation of the compressor and other functions of the high-tech rig is the Atlas Copco Rig Control System (RCS). This system also facilitates wireless remote tram­ ming, auto-levelling, auto-drilling, remote reporting functions and GPS navigation. Other factors underpinning De Veth’s confidence in the Pit Viper includes the single-pass drilling capa­ bility. “Just the advantage of being able to drill a 12.2 m clean, single hole with the lead rod has been very advanta­ geous to us with some of the interbur­ den shots,” he says. “The new breakout system on the machine is unbelievable – it is better than anything we’ve seen

before. The drill is just a lot quicker and smoother to operate.” But there’s also another important benefi­t, De Veth says. “The operators don’t get tired. Everything is easy and accessible from the seat so you come out of the drill still fresh and alert. And that’s a big thing on the night shift.” Besides the PV-235, the drill fleet consists of two DM25 rigs and one DML HP. Two bigger PV-275 units are on order for delivery in 2013. Atlas Copco has supplied more than a dozen Pit Viper rigs to customers in Queensland, all equipped with the computerised RCS automation technology.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction No. 2 2012.

Blasthole Drilling in Open Pit Mining

Russia, Kuznetsk Basin, Siberia,

Boosting Siberian energy Standfirst Economic growth in southern Siberia is increasing year-on-year and at the Kuznetsk Basin coal field, new mining enterprises are appearing and existing operations are introducing the latest equipment to boost their productivity.

The DML expectance The Kuznetsk Basin (Kuzbass) is well known for its huge coal resources, half of which, some 693 million tons, are coking coals, the main commercial fuel for smelting iron. Today, more than 100 underground coal mines and open pits are in production with, 17 coal cleaning plants producing different grades. Annual production of power station and coking coals is some 1.5 billion tons. Drill-and-blast contractor AzotCher nigovets Ltd. offers blasted material preparation for the open pit Chernigovsky mine with an annual production of some 6 Mt. “In our f leet there are only foreign rotary blasthole drill rigs,” says Vladimir Bornev, site supervisor. “We drill blocks with five rigs, three of which are Atlas Copco DML rotary blasthole rigs.” The plan for 2007 was to achieve 1.1 million drillmeters and by the 11th month, the company was well on track to meeting this goal. Comparing the DML rigs, the most popular in Kuzbass, with their domestically manufactured counterparts, Bornev says that the Atlas Copco rigs are very productive and maneuverable, with the powerful diesel engine and compressor productivity among the main benefits. “Local rigs achieve a maximum of 10,000–11,000 drillmeters per month, while the plan for our DML is 20,000–22,000 drillmeters per month,” he says. “In fact, one of our drill rigs has broken all records at the mine; in August it drilled 30,500 meters. The DML rigs are built much better, quality-wise, and the design is more sound and reliable.”

The successful Azot-Chernigovets team at the Chernigovsky open pit: (From left) Vladimir Klimov, operator, Oleg Grebenshikov, operator assistant; Dmitry Kuznetsov, foreman; Vadim Khlebunov, deputy chief engineer; Vladimir Bornev, drill site supervisor; Victor Yarkov, operator and team leader; with Yury Dolgov of Atlas Copco.

Victor Yarkov, operator of the recordbreaking DML, says, “The cabin is well insulated, with good visibility and operating lights. Also, the control levers are comfortably located.” Yarkov has worked here for almost 20 years and says good teamwork also contributes to the successful drilling. At Chernigovsky, tricone drill bits are used for the 203 mm and 270 mm blastholes with 9-meter pipes to depths of 5-15 meter. The performance of the rotary head is 100 rpm at 10.575 Nm and the compressor capacity is 34 m3/min at 758 kPa. “Water in the coal beds is about 50 percent, and in some sectors even more,” says Vadim Khlebunov, deputy chief engineer of Azot-Chernigovets. “This, combined with fissuring, often makes drilling and blasting a problem. However, the rig performance is excellent and if you follow the manufacturer’s recommendations, there will be no problems at all.” The contractor produces and uses two types of emulsion explosives for dry and wet holes. “We provide a complete technology process,” comments Khlebunov. “We sell fully prepared cubes of rock mass and run operations

both at Chernigovsky and at a number of other open pits.” The set task per shift for the DML is 400-500 drillmeters, so it achieves 800-900 drillmeters per day over two shifts. Says Khlebunov, “We hold a record of 1,300 drillmeters per day. Our success is the result of co-ordinated efforts by all those involved. We want to prove what the drill rig and the enterprise is capable of.”

Bachatsky open pit At the Bachatsky open pit, owned by Kuzbassrazrezugol, the average thickness of the coal seams is 32 meters. Here, too, the main goal is to increase productivity at minimal cost. The rig fleet has been completely renewed; the previous 14 electric drill rigs have been replaced with four diesel and two electric rigs. Two DM-M2 and two Pit Viper 271 rigs are in use and the miners are happy with the equipment. Alexander Bogatiriov, deputy technical director, says, “Though the rigs belong to different classes, I think they are equal in terms of productivity. Operators hold the same opinion; the DM-M2 is not second to the Pit Viper.

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Boosting siberian energy

Competition between the rig operators produces such great results with the DM-M2 as 30,600 drillmeters per month and with the PV-271 37,000 drillmeters per month, which can be compared with a performance of some 8,000 drillmeters per month for the conventional Russian drill rigs.

Single-pass capability The first drill rig was commissioned in 2004 and was the second such drill rig in Kuzbass. To increase productivity, the management decided it wanted single-pass drill rigs and the Pit Viper proved to be the ideal choice. “We have practically reached the maximum theoretical productivity capabilities of the rigs,” says Bogatiriov. “As for maintenance, we observe Atlas Copco factory recommendations. Earlier, the lifetime of the locally manufactured machines was five to seven years, but with the new machines, we expect 10 to 12 years.” Atlas Copco’s local distributor, Mining Solutions, is responsible for staff training and maintenance of the rigs. Engineer Vladislav Grebnev, deputy general director, says, “We have had people on this site from the start, working hand-in-hand with the customer to steadily boost the productivity of the equipment. “The operators traditionally believe that productivity increases depend solely on torque. Pulldown force was not taken into account. We worked together as a team and the rigs started achieving 18,500 meters per month. That was the start of the productivity increase.” The company provides three types of service contracts: a complete service, including night duty; setting up, diagnostics, parameter monitoring; and emergency call-out. Today, 40 units of Atlas Copco equipment are covered by the service contracts and practically all customers extending their contracts choose the full-service option. Service contracts are applicable to all rotary drill rigs including DML, DM45, DM-M2 and Pit Viper 271s in the region.

Acknowledgements A winter’s day at the Bachatsky open pit: The Atlas Copco drill rigs DM-M2 and Pit Viper 271 help to produce coal for both the domestic and international markets.

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This article first appeared in Atlas Copco Mining & Construction No. 1 2008 Blasthole Drilling in Open Pit Mining

USA, powder river basin, Wyoming

Hidden treasure beneath America's western prairie Multi-pass drills meet demand Much of the world relies on coal for electricity generation. This is especially true in the United States, where coal is responsible for over 50 percent of the power produced. To meet this need, over 1 billion tons of coal is mined on an annual basis. The proven DM-M3 and now the PV-275 are the drills of choice in large scale mining operations in Wyoming. These robust drills, with their ability to drill large deep holes at an angle, have become the standard in the Powder River Basin.

Powder River Basin Under the rolling grasslands of northeast Wyoming, massive seams of lowsulfur, sub-bituminous coal are mined on a scale unmatched anywhere on earth. The Powder River Basin (PRB) is home to 13 major open-pit coal mines, all of which would be considered large in their own right. Combined, these mines tallied 451 million short tons (410 million metric tons) of coal production in 2008. Individually, the PRB is home to the 10 largest coal mines in the United States, and quite possibly the five largest in the world. Two mines, Peabody Energy’s North Antelope/Rochelle Mine and Arch Coal’s Black Thunder Mine, each produced over 88 million short tons (80 million metric tons) in 2008. The key to the success of these mines is the thick coal seams, which can exceed 80 feet (24 meters) high. While the geology may seem very favorable, strip ratios continue to increase as mining progresses. Many of the mines now average 3 cubic yards of waste to 1 ton of coal. This translates to overburden cover in excess of 300 feet (91 meters) in many areas. Therefore, to meet the

Massive amounts of overburden - up to 300 ft (91 m) - are removed to reach the seams of coal that can exceed 80 ft (24 m) thick. Powder River Basin coal is treasured because of its low sulfur content.

high coal production, an enormous amount of overburden must be moved.

Dragline operations When moving this amount of material, mines turn to the lowest cost equipment available. Many of the PRB mines utilize large walking draglines as their

primary stripping tool. Draglines are very cost-efficient earthmovers as they utilize massive buckets (up to 160 cubic yards, or 122 cubic meters), and deposit their material directly without need for haulage units or conveyors. Unlike a shovel or loader, which has a limited digging height that dictates the bench height (usually less than 60 feet, or

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Draglines are effective earthmovers, removing overburden and depositing directly into spoil piles as shown here. In the foreground, casted material can be seen filling the empty pit, while dozers work to build a dragline bench.

A dragline digs on the spoil side of the pit. Draglines move in small steps via a cam-type walking mechanism.

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18.3 meters), a dragline is capable of deep digging depths beyond 100 feet (30.5 meters). While the dragline is a very effective earthmover, the overall cost of overburden removal can be reduced through cast blasting. Cast blasting is a method of drilling and blasting that uses high explosive energy to throw a sizeable portion of the bank into the adjacent empty pit where the coal was previously removed. This method often results in casting 30 percent or more of the bank overburden material to its final resting place, known as the “effective cast” or “cast to final.” As dragline operations require a flat bench, large track dozers with special wide blades (sometimes referred to as carrydozers) push the cast material down and build a bench at a set height above the coal seam. The dragline will then uncover the coal seam. This mining Blasthole Drilling in Open Pit Mining

Hidden treasure beneath America's western prairie

method allows for the excavating of a large vertical block of material ranging from 100 feet (30.5 meters) to 200 feet (61.0 meters) or more in depth, compared to the 50-foot to 60-foot (15.2 to 18.3 meter) vertical benches taken by truck/ shovel methods. A challenge of the dragline method is maintaining stability of the face (known as the highwall) after excavation, especially when water is present in the material. Drilling for cast blasting applications generally involves deep depths (up to 235 feet or 71.6 meters), large diameters (up to 12 1/4 inches, or 311 mm) and angles up to 30 degrees from vertical. Large diameters result in wider drill patterns, reducing the number of holes drilled. Because of the size of the dragline buckets, large fragmentation size from the blast is not a concern. However, some operations have found that smaller diameters such as 11 1/4 inches (286 mm) yield better blasting results with the tighter spacing. Deep blasthole drilling has its challenges. Foremost is the amount of cuttings generated by the large diameter, deep holes. A 12 1/4-inch (311 mm) hole to 200 feet (61.0 meters), assuming a swell factor of 30 percent, would yield 7.9 cubic yards (6.0 cubic meters) of cuttings. This is a very large pile that smaller drills simply cannot contain under their dust hoods. Even though a small unit might have sufficient pulldown, rotary torque and air to drill a hole, it wouldn't be effective due to excess cuttings falling back down the hole after the hood area is filled. Most of the drilling for dragline operations is done at angles between 20 and 30 degrees. The angle drilling serves two purposes. First, the angle can be set to roughly the same angle as the desired highwall. This is done to help keep a consistent face-row burden to improve the effectiveness of the cast shot. In simple terms, the burden at the top of the highwall (the crest) should be similar to the burden at the bottom of the highwall (the toe). Second, angle drilling can help shape the direction of the cast shot. As the blast projects perpendicularly from the bore hole, an angled hole gives a vertical component to the blast, helping lift the material and therefore throw it further. It is

Drilling at an angle then blasting the bank into the adjacent empty pit results in casting 30 percent or more of the bank overburden material.

important to remember that the drilling depth increases as the angle increases. For example, if mining a 200-foot (61.0 meter) bench, the drilling depth at 30 degrees would be 231 feet (70.4 meters). Some mining regions are fortunate to have soft material, which yields extremely fast drilling rates and less wear on buckets, tires and truck beds. The PRB is in this class, with much of the material having a compressive strength of less than 5,000 psi (34 MPa). The

material is so soft that tricone bits are rarely used. Instead, aggressive clawtype bits are the standard. Contrary to the general belief that soft material calls for as high a rotation speed as possible, these claw bits rotate at lower RPM (100 or less), but their design allows them to shear through the material at rates exceeding 1,000 feet/hour (305 meters/ hour). To handle the high penetration rates, large air compressors must be used. This is especially true in the PRB as these

Drillers on the DM-M3 appreciate the clear view of the breakout wrench and easy access to controls.

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The 235-ft drill depth of the DM-M3 allows the dragline access to the deep coal in one blast. The DM-M3 can drill at an angle of 30 degrees, which maintains the angle of the highwall and helps shape the direction for the cast shot.

Good highwalls are a result of proper drilling and blasting and bench preparation. The dragline seen here is using the spoil side stripping method as this pit nears completion.

drills often use smaller diameter drill rods to increase the annular area (the gap between the wall of the hole and the drill rod) to allow the larger cuttings generated by the claw bit to exit the hole without having to be reground to a smaller size. High volume compressors of up to 2,600 cubic feet per minute are used, and it is important to have sufficient air pressure (100 psi, or 6.8 bar, or more) available to prevent plugging bits. Because of the light weight of the overburden (approximately 3,000 pounds per cubic yard, or 1.04 tons per cubic meter), bailing velocities may dip below the 5,000 feet per minute (1,524 meters per minute) recommendation that the industry would normally prescribe, yet still effectively clean the hole. 162

Building drills for the PRB Atlas Copco’s DM-M3 and Pit Viper 275 (PV-275) are ideal for coal mining in the Powder River Basin and the DM-M3 was, in fact, first designed for mining the overburden in the PRB. Jon Torpy, a regional manager for Atlas Copco, said, “The DM-M3 is in a class of its own with the right balance of air, rotary head performance, bit load, and depth capacity. The PV-275 has taken these strengths and added to them. The DM-M3 was designed to drill the Powder River overburden so it can drill the deep angle holes required to reach the coal.” Walt Schroeder is a product support sales representative for Atlas Copco, but prior to working for Atlas Copco,

Schroeder was a driller. He has operated many drills including seven years on a DM-M3. Schroeder said, “I have never had a bad word to say about the DM-M3 and it’s always the truth. Ask anyone who has operated one. There is no other drill that can mast over to 30 degrees and drill 240 feet – all day, every day and never even grunt!” Schroeder added, “When this rig was designed there were definitely miners involved. There isn’t a more comfortable rig to operate; they got it right when they engineered this rig. I’d say this is the most ergonomic drill on the planet and I’ve never run a rig that I like more.” Schroeder’s confidence speaks to durability, too. Availability is critical according to Schroeder. “There is not a drill made that has the air, power and overall drilling performance at this depth and angle that can match the availability of the DM-M3. I know guys you wouldn’t let operate your lawnmower who are drilling with the DM-M3 – this rig is tough!”

Acknowledgements Story and pictures by Brian Fox and Scott Ellenbecker. Portions of this article first appeared in Mining & Construction USA, No. 1, 2009.

Blasthole Drilling in Open Pit Mining

USA, gilette, wyoming

Finding a perfect balance Dry Fork balances ecology and mining As one of the newest coal-fired power plants in the nation, Dry Fork Station is a testament to how nature and progress can coexist. In fact, technological advances in drilling equipment, coupled with ecology-conscious coal-mining management, ensure that a responsible and mutually beneficial relationship between all stakeholders will continue well into the future.

Award-winning mining operation Dry Fork Mine is a surface coal mine located in the Powder River Basin approximately seven miles northeast of Gillette, Wyoming, on Garner Lake Road. Constructed in 1989, commercial operation began in 1990. Approximately 70 employees work in the mine, which is well known for its safety and environmental achievements. In 2009 the mine celebrated having gone nearly seven consecutive years without a lost time injury, and it recently received three prestigious environmental awards, including the Office of Surface Mining (OSM) Excellence in Surface Mining Award; the Wyoming Game, Fish Industry Reclamation and Wildlife Stewardship Award; and an Excellence in Surface Coal Mining from the Wyoming Department of Land Quality. Wester n Fuels–Wyoming, Inc. (WFW) is owned by a collective of cooperative power companies. The mine primarily supplies coal to the utilities associated with those rural cooperatives. Dry Fork is an industry showcase representing how mining, energy production and nature can realize sustainable success. Dry Fork balances mining operations with conservation practices. The mine’s 24/7 operation produces an estimated 5 to 6 million tons of coal annually, of which 1.5 to 2 million

The mine has won several prestigious environmental awards for achievements. Reclamation at the award willing property includes returning the land back to its original contour and elevation. Wildlife is abundant in the area. A herd of dear graze in the distance at the edge of the newly scalped landscape.

tons will be used in the new Dry Fork Station, a 385 megawatt power plant located adjacent to the mine. The Dry Fork Mine is a truck and loader operation with Le Tourneau 1850 and 1400 loaders and Cat 793D 240 ton and 789B 190 ton haul trucks. The drilling is done with a new Atlas Copco DML blasthole rig with the new Atlas Copco Secoroc Grizzly Paw 10  ⅝ inch (270 mm) bit. In the past, the mine drilled 9 inch (229 mm) holes with an older rig, but with the new DML they were able to increase hole size, which allowed them to expand their pattern by nearly 30 percent.

As good as new Every element is part of the mine’s reclamation plan. Animals, trees, surface rocks – it is all documented in the permitting process. Director of Regulatory Affairs Beth Goodnough is the keeper of the permit. “It’s a constantly evolving permit. Currently it’s 25 volumes long and growing.”

Goodnough sited specifics to the remediation plan: “We make efforts to replace wildlife microhabitat impacted by mining by replacing shrubs, building rock piles, planting trees and bushes, and installing rock and bluff type ledges in the reclamation. The permit requires us to restore one shrub per square meter on 20 percent of the reclamation. The seed mixes are rather complicated and include the Wyoming big sagebrush, silver sagebrush and a variety of native grasses and forbs. The mixes are tailored to grassland areas, wetlands, bottomlands, shrub patches and mixed sagebrush/grassland post mine areas.” To support habitat, rock outcrops are also replaced where the integrity of the rock makes it possible. Another recently constructed feature is a 4 acre alluvial valley floor that was recreated in a reclaimed area to look similar to the one that had been present prior to mining. In another area, the mine has succeeded in establishing a wetlands channel and has three restored wetlands ponds. In

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This DML drill rig uses the new Secoroc Grizzly Paw bit to drill through coal and overburden. The coal is drilled at a 20 degree angle.

addition to reclamation, all climate and sub terrestrial elements are examined and monitored. “Wetlands, hydrology, air quality, climatology, archeology, wildlife — everything is monitored, documented and reported monthly or annually. I see different in-spectors once or twice a month, federal and state, we have a variety of folks with different focuses watching what we do,” said Goodnough. As for how close reclamation efforts are to pre-mining conditions, Goodnough said, “We’re trying to do in 10 years what it took nature hundreds of years of evolution to accomplish.” In total the mine manages approximately 10,000 acres (40.5 km2) of land. Of the mined area, nearly 20 percent of what has been disturbed has been reclaimed to what it was, before any mining activity. Goodnough said the goal is to restore disturbed land right behind mined land. “We want a one to one ratio as we go forward – an acre reclaimed for an acre disturbed.” Dry Fork isn’t alone in its efforts to keep the Powder River Basin sustainable. The region is known for following thorough reclamation processes. 164

The right machine The DML is a new drill for Dry Fork, but drill operator Mark Lindsey said, “It didn’t take but a couple weeks to get comfortable with the controls. I like the carousel system: it’s very user friendly. There are good safety features on this rig, too, keeping you from screwing up.” Lindsey thinks the drill has “lots of air power and drills fast overall.” The DML is outfitted with a 1900 cfm air compressor. As for the technology factor Lindsey said, “I wasn’t too sure I’d like the drop GPS, but now I’m spoiled because the depth is always right on the money. Now I really like it.” Mine Superintendent John Barnes said, “It’s an advantage with the larger diameter hole because we don’t have to shoot daily.” He likes that the driller, Mark Lindsey, can be doing other things and they can stay ahead. Each blast usually requires 35 to 40 holes. When overburden is less than Deeper than 30 feet and they drill on a 60-feet (18 m) deep, 20-degree angle. The overburden is generally 60 feet deep. He said, “The Grizzly Paw bit

performs well when drilling through rock.” The drill’s penetration rate is typically around 25 to 32 feet per minute (7 to 10 m/min). Dry Fork is toward the north end of the Powder River Basin producing higher moisture, low sulfur, sub-bituminous coal at 8,000 to 8,200 btu per pound. The mine has two pits with coal of different properties, which allows the mine to mix loads to a power plant’s specifications. Coal depth is a varying factor in the Powder River Basin coal region. This makes reclamation a bit more difficult too. Barnes said, “We map everything to ensure post-mining contours coincide with pre-mining elevations. This includes setting topsoil aside during initial excavation so it can be replaced after reclamation. Basically the reclaimed land will look just like it does before, just lower because the coal has been removed.” The coal in this part of the Powder River Basin exists in two layers. Barnes said, “The coal deposits came in two events.” The mineable Anderson layer is on top, which is about 18 feet (5.5 m) thick and the lower Canyon deposit is generally 55 feet (16.7 m). A sedimentary stratum about 6 ½ feet (2 m) thick separates the two coal seams. When drilling in coal, Lindsey said, “The Grizzly bit drills like a hot knife in butter and its easy drilling. It won’t plug up either.” When drill hole depths allow, both overburden and coal are drilled in a staggered pattern at a 20 degree angle. To be successful here, a mine has to employ efficient and intelligent people and equipment. Getting the coal is just one part of a process that ends in reclaimed land.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 3 2010. Story and photos by Scott Ellenbecker, Ellenbecker Communications.

Blasthole Drilling in Open Pit Mining

USA, Vansant, virginia

Moving mountains

Virginia Drilling now has over 50 Atlas Copco drill rigs in its fleet.

A focus on the coal industry In the southern Appalachian range of West Virginia, Kentucky, and Virginia, known as the Blue Ridge Mountains, the seam of coal flows through the ground at varying depths, sometimes just at the base of the mountain. To get the coal Virginia Drilling Company works with their coal company partners to shave off the mountains one 30-ft to 40-ft lift at a time. Virginia Drilling’s business philosophy has developed over time but has remained simple, says said founding partner and company president Verlo Stiltner. “We grow the business by focusing on what you do best and surround yourself with experts.”

Virginia drilling In 1998, partners Verlo Stiltner, David Hale and Mike Sheets started the contract drilling company Virginia Drilling to diversify the existing blasting business, Austin Sales, owned by Hale and Stiltner. The company began as a contract driller on construction applications with Ingersoll-Rand ECM 490 and ECM 690 crawler rigs. Today the company has grown to include 28 Atlas Copco DM45’s, nine Atlas Copco DML’s and seven Atlas Copco crawler drills in various sizes, including one ECM 490 and one ECM 470 and two ECM 690’s and three ECM 720’s. Virginia Drilling is the largest, if not the only, contract driller in the world focused primarily on the coal industry. Even the smaller construction crawler

drills are dedicated to road, reclamation and underground mine face-ups to a point that 85 percent to 90 percent of the work is for the coal mining companies. Two years ago, the company’s cofounder David Hale passed away, but the business has continued to grow with strong leadership and committed employees. Today the company has 18 drills on order and has a steady business growth plan slated for years to come.

Getting started Because of the existing blasting business, Virginia Drilling knew everyone in the area. Founding partner and construction drilling manager Mike Sheets summed it up, “the coal industry in the region is a real fraternity.” Just over a year after starting the business, which

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until that time had focused on construction projects, Virginia Drilling partners were approached by a coal company who knew their blasting expertise and asked them to drill in the coal field. The premise was to not waste blasting material on the bench, to work efficiently and maximize outside resources. The goal was to get costs below industry average and have higher drill utilization.

Partner responsibilities

Two Atlas Copco DML drill rigs prepare for the next shot that will lower the bench to the coal seam.

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From the beginning Virginia Drilling’s partners accepted that they were not drill experts. Admittedly, Virginia Drilling Chief Operating Officer Clinton Evans pointed out they had lots to learn and wanted to work closely with drill dealer Brandeis Equipment to develop a maintenance program. “When choosing a drill it was really a no-brainer,” said Evans. They went with Atlas Copco because if its product reputation, but also they needed a strong dealer that would support every aspect of the drill including parts and support. According to Brandeis branch manager, Barry Justice, 40 percent of their parts inventory is for Atlas Copco Drills. “If the drills don’t run, the whole mining process stops,” said Justice. Brandeis has 19 service trucks in the field, running its parts department on a double shift and supplying 24/7 service to Virginia Drilling. All that attention equates to a higher performance on the drills. The oldest drill in the fleet is a 1999 DML with 22,000 hours. Typically on a mine site the cost of drilling equipment is approximately 5 percent to 10 percent of the total expenditures. This is another reason why some mining companies don’t focus on their drilling. Virginia Drilling knows that the excavation equipment can catch up to them but can’t pass them. Atlas Copco regional sales manager Tom Borer said, “Virginia Drilling has drills with 20,000 hours on them that run better than drills owned by others that have 10,000 hours.” There is no big secret here; it’s all in the preventative maintenance (PM) program. The main pumps, for example, average 7,000 to 8,000 hours for most, Blasthole Drilling in Open Pit Mining

Moving Mountains

Shouldering the burden for the coal companies. From left: Mike Sheets, Clinton Evans and Verlo Stiltner of Virginia Drilling.

while Virginia Drilling averages 11,000 to 12,000 hours. It’s not uncommon for Virginia Drilling to get 40 percent greater life out of their drill components because of the PM program. Mike Sheets said, “It’s all about taking away problems.” Brandeis takes the burden of maintenance away from Virginia Drilling and Virginia Drilling takes away the burden of drilling and blasting from the coal companies. He emphasized that his customers’ focus is to move material. They don’t want to worry about getting the shot right or all the liability that comes with explosives. Sheets said, “If everyone focuses on the part of the business that makes them money everyone wins, and if we’re not drilling holes, we’re not making money.” To ensure they are drilling holes they follow the PM program religiously. If a drill is close to a scheduled PM and a Brandeis truck is in the area, they will perform the service rather than let it get behind. As a contract driller for many mining operations in the area, Virginia

Drilling takes total responsibility for the drilling and blasting operation. The agreement with its customers is a winwin for everyone. When this part of the business began and the deal was laid out for the customer, he didn’t believe it. “He told us it seemed too good to be true,” said Sheets. They proposed a sliding scale based on 50,000 to 1 million yards of shot material with discounts built in for volume. Virginia Drilling guaranteed the product amount in the customer’s timeframe. They absorb most costs related to putting the product on the ground, from equipment to human resources to blasting material. “When we finished making our proposal the first response was ‘where do I sign,’” said Sheets. Today Virginia Drilling´s client list is long and growing.

Training equals success People are a critical part of making this work. At any one time Virginia Drilling has seven to eight drill trainees, with

that number going as high as ten. The training program has developed over time to what it is today, a well executed system. For the first two weeks they mostly watch and listen. They learn how to set up on the bench, put the mast up and down and terminology. They learn by watching and listening. “We prefer they don’t even come in with experience,” said Evans. They don’t want new employees to have bad habits and to learn drilling according to the company’s operation. After they have a couple weeks with the best drillers they come in for classroom work. They learn down pressure, rotation, penetration rates, bit performance and compressor and engine operation, everything they need to know about the drill and what its responsibility is for drilling the hole. Then the trainees go back in the field with the experienced driller again to apply the classroom work. Every month drillers are evaluated to make sure they are getting optimum production, maximum penetration and bit life

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Blasting off the top – benching down to the coal that can be seen at the base of the mountain.

and overall efficiency. But, all the aspects of training come right back to keeping the drill working at its maximum performance rate. “We expect to get 30,000 hours from our drills,” said Evans. The drillers have to be doing their job correctly to ensure that level of equipment life. 168

Performance for results Drill performance also factors into how Virginia Drilling bids a job. “Everything is evaluated when looking at the cost per foot,” said Sheets. “Because we look at all aspects of the drilling and blasting process, we know how to find our efficiencies.”

One drill site may run into five different layers of sandstone in a mine. Laminated charts plot out the geology of the mine. The goal is to get the maximum penetration in relation to the time in the hole. “The bit is an integral part of the operation,” said Evans. Bits give you the data as to how the drill is performing. Weight and rotation is applied to the bit according to the situation. In this area a driller may expect to get a penetration rate of 6 feet a minute at 165 rpm and 15,000 lbs. Although bits have an optimum rotation rate its only half the equation. “We are not willing to sacrifice a drill to drill faster,” said Clinton Evans. Virginia Drilling looks to maximizing the relationship of down pressure to rotation rpm to ensure the life of the drill. Using 7 ⅞-inch to 9-inch bits on its DML’s and 6 ¾-inch to 7 ⅞-inch bits on its DM45’s, operating between 2,500 to 4,000 hours a year, Virginia Drilling projects 2 ½ million yards of rock a month. It is expected that each drill is responsible for 500,000 yards. The DML’s are equipped with 6 ¼-inch x 30-ft pipe, while the DM45’s run 5 ½-inch x 30-ft pipe. Virginia Drilling can move drills if needed, and to meet the required tonnage they will run three to four drills per site at one time with a maximum of five. Evans prefers the DML because it is beefier from the frame up, but the performance and hole sizes dictate what drills will be used. It goes back to blasting – try to make the pattern smaller but get the most value from the caps, primers and explosives. Generally, hole spacing is on an 18-ft x 18-ft pattern. The 7 ⅞-inch hole can support 16-ft to 18-ft spacing, while the 9-inch hole can do a 19-ft to 21-ft spacing. Virginia uses a 70/30 ANFO emulsion blend as an explosive.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2 2008. Story and pictures by Scott Ellenbecker, Ellenbecker Communications.

Blasthole Drilling in Open Pit Mining

USA, london, kentucky

Cost busting

Ron Johnson, Atlas Copco Regional Sales Manager for Eastern U.S. coal region, and driller, Kevin Maggard.

Controlling drill pipe erosion keeps drill steel costs down Sixteen-year veteran driller Kevin Maggard proudly lis ted several reasons he rates his tenure with James River Coal Service Company (JRCSC) so highly. At the top of his list is the way they keep their equipment up. “Their maintenance program is second to none,” he said. One look inside Maggard’s blasthole rig cabin leaves no doubt that he cares about his equipment. He keeps it so clean it looks brand new.

Maggard is also proud of his current role in the company’s field testing of Atlas Copco Secoroc Teamalloy™ drill steel to bring drill steel cost per hour at JRCSC’s Montgomery mine back down. Regulations two years ago caused changes in the mine’s blasting plan that took its mild steel drill pipe

from 400 hours of life down to just 130. Operations such as this in eastern Kentucky have limited their blasthole diameter to 6 ¾ inches and brought their blast pattern in from 18 by 18 to 16 by 16 feet. Reducing bit size, however, completely reconfigured a highly productive drilling formula that had evolved over years of careful engineering and practical experience with these drills in this mine’s ground conditions. In effect, maintaining regulatory compliance doubled and in some instances tripled the drill steel cost per hour drilled. So JRCSC has been working with Atlas Copco to come up with a solution to get drill steel cost per foot drilled back down to reasonable levels. Maggard has been central to the team effort, which uses his rig and his drilling skills as their test bed. Because drill pipe can run so long between changes, JRCSC finds it best to calculate the “drill steel cost per hour” by dividing the total cost of the drill pipe by the total “air compressor hours” logged between installing the

pipe and removing it. This gives them a reliable and simple basis on which to make a comparison.

Less costs more The cost increase affects JRCSC across its entire drill fleet, which represents a variety of manufacturers. When the large blasthole crawlers were drilling with 7 ⅞-inch rotary bits on 5 ½-inch mild steel drill pipe, bailing velocity (BV) was almost ideal at 6,000 feet per minute (fpm). Glenn Sharpe, JRCSC drill mechanic in the Montgomery mine, said, “The drill made little ‘volcanoes’ at the hole made of chips the size of your fingernail.” Sharpe explained that putting 6 ¾inch bits on the same 5 ½-inch pipe decreased the annulus so much that it doubled the BV to 12,000 fpm. The increased velocity mashed the sandstone into grit that scoured the mild steel drill pipes so aggressively they lasted only one-third of their normal life compared to when they were used to make 7 ⅞-inch holes.

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Above: Driller Kevin Maggard pointed out that by resisting erosion, TEAMALLOY drill steel maintains its stiffness, spinning true with less vibration. This increases bit life and prevents premature bearing failure. (Top right) Ron Johnson compares bearing play of a bit used before drilling with TEAMALLOY against a new bit to show how the cost of mild steel was more than just replacing pipe. (Bottom right) Johnson indicates how little the steel has worn after nearly 400 hours of use, maintaining its relationship to the deck bushing. Mild steel did not often last more than 130 hours in the same conditions.

Their tricone bits also suffered in these holes, their inserts shearing in half in the various sandstones of the Montgomery site. But the rate at which drill steel wore down posed a new problem. The gap that quickly widened between the steel and the deck bushing gave dust an escape-way. There was a risk it would not be captured effectively by the rig’s dust control vacuum. To operate a rig with uncontrolled dust would put the mine in jeopardy of violating dust level limits. So the mine had to switch drill steel out frequently to keep that gap tight. The result was that JRCSC’s rigs were now going through drill steel three times faster than before.

The solutions Sharpe complimented Maggard’s skill as a driller. While Sharpe has seen some drillers go through a top sub in as little as six months, he said Maggard’s drill string is still topped by the original, 6-year-old top sub. It is a certainty that JRCSC isn’t seeing drill steel cost rise from operator fault or poor drilling technique. It’s solely the physics involved in a change of bit size. Ron Johnson, Atlas Copco’s Regional Sales 170

Manager for the 11-state eastern U.S. coal region, performed a complete drill audit, which included an air compressor capacity test. This audit showed that there was much more air than required for adequate bailing, due to the smaller annular area. One solution was to decrease drill steel diameter, so they replaced the 5 ½-inch steel with 5-inch. But this created its own problems. The 5-inch drill steel was not as rigid. Its flexing caused drill string vibration and chatter. Inefficient drilling will also tend to shorten tool life. Sharpe then addressed the air issue. Rather than “choke” the compressor intake to reduce the volume, they not only regulated it down but vented excess volume up the mast to decrease air volume in the hole. As finely tuned as they could get it, the sandstone still rapidly eroded their drill steel.

Teamalloy That’s when Johnson suggested Teamalloy drill steel. Almost every coal company in the eastern U.S. would be keenly interested if Teamalloy were to work for JRCSC. So far it has. While mild steel lasted only 130 hours, the

Teamalloy drill steel was indistinguishable from new at 300 hours. Approaching 400 hours, the steel was starting to show only minimal wear. The wear was controlled and predictable, showing the embedded alloy wear strips slightly more prominently than when new. Johnson predicted they would likely see 500 hours before they changed it out. Maggard said that while drilling he could sense that the Teamalloy pipe offered greater stabilization and perfect rotation. It would seem that JRCSC has found a successful formula once again. Dust is down. Drill steel cost per hour is down. Production is up. And Atlas Copco Secoroc’s Teamalloy drill steel is living up to its billing in their Montgomery mine, the bet that it will beat mild steel in cost per hour in any application, anywhere, every single time.

Acknowledgements This article first appeared in Mining & Construction USA No. 1, 2012, written and photographed by Joe Bradfield, senior writer at Ellenbecker Communications. Blasthole Drilling in Open Pit Mining

Kazakhstan

Mining in Kazakhstan rig, although the rigs have the capacity to operate at 20,000 to 25,000 meters per month. The DML drills a 228 mm hole, while the DM45 drills a 200 mm hole using Secoroc EpsilonTM bits lasting 15,000 to 18,000 meters. Borly also has the distinction of having received the world’s first electric DML drill rig. Meanwhile, the recent delivery of the country’s first Atlas Copco RD20 drill rig for oil and gas, has paved the way for exploration of the huge Karaganda methane field.

Rich mineral resources The electric-powered DML rig with hydraulic tophead drive.

Gearing up for growth The Republic of Kazakhstan, that vast country south of Russia between the Caspian Sea and China, is on the move. Its infrastructure is improving and its mining industries are being reborn through new methods and modern equipment. It will take time, but the aim is clear: to become a prime example of Central Asia’s growing prosperity. Atlas Copco equipment and service is playing a central part in this modernization.

Expansive coal reserves Few countries have such expansive reserves of coal, oil, uranium, methane and natural gas as Kazakhstan. And in this land, characterized by vast open plains, Atlas Copco drill rigs have become the rigs of choice among coal producers. Beneath the surface of the Kazakh Steppe in the north of the country, there are massive coal reserves. Here, Atlas Copco has been working with a number of mining companies to upgrade their

drilling technology to meet productivity targets and lower their costs. Two such operations are Bogatyr Komir and Borly Coal that both operate a mix of Atlas Copco DML and DM45 blasthole drill rigs. Bogatyr, located in the Ekibastuz coal basin, has total reserves of 4.5 billion tonnes and produces nearly 40 percent of the country’s coal (46 million tonnes mined in 2008). The mine has a fleet of five drill rigs on site, three DMLs and two DM45s. Each DML drills around 14,000 meters per month, while the DM45 achieves about 20,000 meters per month. Both types are operating on 25-meter benches. The DML rigs use 228 mm tricone bits, while the DM45 uses 171 mm tricone bits. All of the rigs are capable of producing more drill-meters if required. With a 7-meter burden and 5-meter spacing, each blast consists of 400 holes to produce more than 100,000 tonnes of coal and 60,000 cubic meters of waste per day. Borly, located in the Karaganda region, produces about 7 tonnes per year from the Molodezhniy and Kulchek mines. It uses both DML and DM45 rigs on 45-meter benches, drilling around 17,000 meters per month per

Kazakhstan also has gold, copper, iron ore and manganese open pits. Here too, Atlas Copco drill rigs are well represented. DM45 and DML blasthole rigs are used by Kazakhmys Copper Company and Aktobe Copper Company in the country’s western copper region. The multi-pass DM30 for hole diameters of 127 mm to 171 mm, is the rig of choice for Polymetal’s Varvarinskoye Mine, whereas the single-pass Pit Viper 275, for hole diameters up to 270 mm, is used by Kazzinc’s VasGold mine. “We have introduced blasthole drilling equipment to Kazakhstan that can increase productivity and lower operating costs,” explains John Stinson, Global Business Manager, Atlas Copco, “but it was not a straightforward task.” From the start, Atlas Copco advanced new ideas into Kazakhstan. The region traditionally used a common hole diameter, bench height and annual meterage using electric-powered rotary drilling methods. Atlas Copco converted the country to diesel-powered hydraulic drills, as well as high-pressure down-the-hole (DTH) hammer drilling. Today, the time-tested technology of DTH drilling has proven itself at Varvarinskoye Gold as well at the Aktobe Copper Company’s “50 Years October” copper mine. This change-over to DTH drilling was not always successful initially, but with time and cooperation, they were able to achieve its full benefit.

Blasthole Drilling in Open Pit Mining 171

Coal and Gold Mining in Kazakhstan

On site at the Vararvarinskoye Mine, owned by OJSC Polymetal of Russia, where five Atlas Copco DM 30 rigs and one T3W are used for mining gold.

Progress in “October” Production at the 50 Years October deposit, located some 200 km from Aktobe, started in 2006. During the initial planning stages, they produced a 215 mm blasthole in the overburden through rotary drilling. Once the overburden was removed, they studied DTH drilling for use on harder rock formations. Following these studies, the mine selected eight Atlas Copco rigs—six DMLs and two DM45 high pressure blasthole rigs for DTH drilling with Secoroc QL60 and DHD 360 hammers to drill 171 mm holes on a 12-meter bench with a 5-meter burden and 6-meter spacing. The central pit has a 14-year life and satellite pits are under development. While the owner, Aktobe Copper Company, was impressed with the penetration rate, overall production levels had not reached expectations, so the company turned to Atlas Copco for a way to increase the rigs’ productivity. GRT, a sister company of Atlas Copco’s distributor Ken Group, an experienced contractor, had been getting good results with rotary drilling at other copper mines and wanted to duplicate that success by employing DTH drilling at the 50 Years October site. The company operated a DM45HP rig during a four-month test period. Of 172

the total meters drilled the rig achieved 60 percent of the total productivity rate of all three rigs in operation at the site. According to Alexander Merzlikin, Deputy General Director, Special Projects, Ken Group, there were no technical problems and the drill rigs all achieved the same penetration rate. Ken Group/GRT also coordinated all supplies and service to keep the rigs running at maximum efficiency, including all lubricants, drilling consumables, parts, maintenance and repairs. Merzlikin continues: “When you manage the bench, you need to plan for up to three months. Our success comes from teaming experienced operators with an equivalent service organization and supply chain. Ken Group/GRT has a single focus and that is to provide the maximum meters at the lowest possible cost.” Moving forward, Ken Group—GRT will either expand the contract drilling or offer a structured training and drilling program for Aktobe Copper’s operators.

Developing metals Varvarinskoye Gold Mine in Varvarinka was developed in the 1990s when European Minerals conducted exploration, followed by pit work with overburden removal in 2006. Gold production began in December 2007 with

copper-gold concentrate following in March 2008. Varvarinskoye is located on the northwestern plains close to the Russian border. Recently acquired by OJSC Polymetal of St. Petersburg, Russia, the mine is a good example of the equipment used for mining development in Kazakhstan. To date, the mine has been moving 3 tonnes per year. It operates five Atlas Copco DM30s and one T3W high pressure blasthole drill for DTH drilling. Three DM30s were acquired when the mine opened, and two more were recently purchased, expanding the fleet to meet ore demands. The mine will be developed to produce 4.2 tonnes of ore per year for the processing facility over the projected 15-year life span of the mine. Each rig is expected to drill 20 meters per hour to produce 10,000 drillmeters per month. The drilling pattern consists of a 4-meter burden with 3.5 meter spacing (or 4.5 by 3.7 meter, depending on the rock) with a bench height of 5 meters and sub-drilling of up to one meter. The rigs operate at 24 bar, each applying 55 bar of pulldown with 70-bar rotation. The mine uses 152 mm hammers, with the 165 mm bits averaging 1,0001,200 meters per bit and 10,000 meters on the hammers before they are rebuilt. Vladymir Sterlyagov, Mine Manager at Varvarinskoye Gold, is satisfied with the overall success of the DM30 blasthole rigs. One of these is nearing 12,000 hours. Sterlyagov credits drill supervisor Pavel Bobylev for keeping the rigs at a high rate of productivity. It is Bobylev’s working and drilling knowledge, gained in many different environments, that has allowed this team to get the most out of the DM30 and make them successful. Varvarinskoye has demonstrated the probability for resources of 3.1 million ounces of gold and 313 million pounds of copper.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction No. 1, 2010 Story and pictures by Scott Ellenbecker.

Blasthole Drilling in Open Pit Mining

VIETNAM, HA LONG BAY

Drilling for coal in Vietnam

Within the Vietnamese mountains overlooking Ha Long Bay's karst formations lie the country's largest coal reserve.

Coal mining in Ha Long Bay Coal production is a vital part of the Vietnamese economy, and the country’s largest field has turned to modern drilling technology to optimize productivity and efficiency. Atlas Copco is working with many of the region’s companies, providing them drill rigs of various sizes to meet their specific excavation needs.

A world wonder With its thousands of limestone karst formations that begin in the surrounding mountains and continue to the sea where they stand out as lush, domeshaped islands, Ha Long Bay is recognized as one of the wonders of the world. In those mountains that overlook the bay lies Vietnam’s largest coal reserve. The coal region in Vietnam is centered in Cam Pha in Quang Ninh province, one of the two towns of Ha

Long Bay. Geographically the region is 130 kilometers long, varying from 10 to 30 kilometers wide, or approximately 1,300 square kilometers. Reserves here total 2.5 billion tonnes of sustainable supply. Last year the region’s 70 or more enterprises produced 43 million tonnes, representing 90 percent of the coal burned in Vietnam and 100 percent of the country’s exported coal.

Diverse needs Atlas Copco supplies the mines of the region with rigs matched to the size of their various pits. With a complete product line offering a full range of equipment, and with a staff of technicians there onsite, Atlas Copco meets the specific needs of each of its customers. The majority of drilling in the area is performed by its DML and DM45 blasthole drill rigs. A variety of surface crawlers, including ROC F7, ROC F6 and ROC L7 CR COPROD drill rigs, work in smaller operations. The following is a look at three mines and

the drilling operations that make them successful.

Dong Bac Coal Exploration Enterprise-Dong Bac Corporation produces 140,000 tonnes of coal per year running two rigs. The mine has operated drills from several manufacturers but found its greatest success with the Atlas Copco ROC L7 COPROD drill rig because of its availability. Mr. Vu Van Tan, Chief Operator at Dong Bac, says, “The Atlas Copco drill rigs have similar penetration rates with our other rig, but it’s the uptime of the ROC L7CR that makes it the mine’s most productive rig.” At this mine the ROC L7CR drills a 165-millimeter (6 ½ inch) hole to depths of approximately 8 meters (26 feet). The 6-meter (20-foot) deep coal seam rests at an angle from the surface, which results in drilling to depths that end at varying degrees along the coal seam. Mr. Tan likes the size and mobility of the ROC L7 and thinks it’s the best rig for this size operation.

Blasthole Drilling in Open Pit Mining 173

Drilling for coal in Vietnam

Ptam Trung Kien, Technical Manager for Nui Beo Coal Company in front of their DM45.

Nui Beo Nui Beo Coal Company is a much larger operation working adjacent to the Dong Bac mine. In 2009 the mine produced 5.1 million tonnes of coal using four blasthole drills. Two of those are Atlas Copco diesel-powered rigs.The others are Russian-made electric models. The mobility and faster penetration of Atlas Copco DM45 and DML blasthole rigs significantly out-drill the competitor’s models. The two Atlas Copco rigs drill 8,500 meters per month, whereas the other two rigs drill only 3,000 meters per month. The mine’s three shifts produce 22 million tonnes of waste annually from a pit 4 kilometers long by 1.1 kilometers in width. The projected life extends to the year 2015, with a new property already planned and scheduled for development. Pham Trung Kien, the electro-mechanical department technical Engineer, oversees the drill fleet for the mine. Of all these drills, Kien likes the DML the most. With its Cat engine, he thinks it offers more power than the DM45, but both are more productive and efficient 174

than other drills they have operated. Although he has had no major problems with his Atlas Copco drills, he likes the fact that Atlas Copco and Caterpillar have support people in the area to assist if he should need them. The DML and DM45 blasthole rigs in the area use 230-millimeter (9-inch) Secoroc tricone bits and 7-meter (23foot) rods. At Nui Beo, operations are currently 100 meters (328 feet) below sea level on 20-meter (60-foot) benches. Drilling is done at an angle of 10 to 20 degrees at an incline of 5 to 10 percent.

Tay Nam Da Mai In comparison, Tay Nam Da Mai Joint Stock Corporation also operates the DML, currently drilling at bench elevations 40 meters (130 feet) above sea level. The coal seam is about 40 meters below sea level. Benches are 16 meters (52 feet) in depth on a 6 by 5 meter pattern (16 by 20 feet), which is common in this the area. Measuring 1.8 kilometers long by 1.5 kilometers wide, this mine produces 1 tonne of coal for every 9 to 10 tonnes of waste. It yielded one million tonnes

Tay Nam Da Mai prefers the DML drill rig.

of coal last year and will produce 1.5 million tonnes this year. Here the DML drills 5,000 to 6,000 meters per month in the mine’s harder rock and 8,000 to 9,000 meters per month in the softer formations, with another 15 years of life at the current production rate. Mr. Hoa, Deputy Manager Electro Mechanical department says, “I like the durability of the Atlas Copco rigs and their ability to drill more meters.” Because the competitive rigs have less availability and drilling performance is less, “It takes the (competitive rig) a year to drill the same meters the DML will drill in three months.” Because of the variations in pit size and desired production, the Quang Ninh province is well served by Atlas Copco’s product line, with the DML as a leader in the class.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction No. 3, 2010. Story and pictures by Scott Ellenbecker.

Blasthole Drilling in Open Pit Mining

DRILLING METHOD GUIDE

Blasthole Drilling in Open Pit Mining 175

DRILLING METHOD GUIDE

Drilling method guide Different applications and rock conditions need different kinds of drilling equipment and performance. This guide is an attempt to start a discussion around the method and equipment that might provide the ultimate solution for an application. Below, we compare six different drilling methods on offer from Atlas Copco.

The tophammer method

In percussive tophammer drilling the impact energy is generated when the piston is striking the shank adapter. This energy is transmitted from the rock drill via the shank adapter, drill steel and drill bit to the rock, where it is used for crushing. The entire system of rock drill, drill steel, drill bit, rotation, feed force and flushing must harmonize for maximum drilling economy. The tophammer method is primarily used for drilling in hard rock for hole diameters up to 5 ½ inch (140 mm), and the main advantage is the high penetration rate in good solid rock conditions. Handheld pneumatic rock drills are used for small hole diameters while rig mounted hydraulic rock drills are commonly used for hole diameters above 1 5/8 inch (41 mm). Heavy hydraulic rock drills with an impact power of up to 40kW are used for large hole diameters up to 5 ½ inch. To maintain good drill steel economy and hole straightness heavy extension rods or rigid guide tubes with large outer diamer have to be used.

176

The COPROD® system

The COPROD system combines the speed of tophammer drilling with the precision and long service life of the down-the-hole method. Inside each rigid, threaded pipe section is an impact rod. It is furnished with stop lugs to hold it in place inside the pipe section. The COPROD sections are joined together via the drill pipes. Since the drill pipes transmit rotation force only, stress to the threads is minimal and their service life very long. All negative effects of the transmission of impact energy through the threads are eliminated entirely. The result is high impact power with minimal wear. Since the outer pipes are smooth and flush along the entire length of the drill string, it is almost impossible for jamming to occur. Practical experience with COPROD has been exceptionally good. The method gives good overall economy, particularly in large scale production drilling and when drilling in fissured or otherwise demanding rock conditions.

The down-the-hole method

The down-the-hole method is a reliable way to drill in various formation from hard to soft, competent to broken or abrasive to non abrasive rock. The rock drill piston strikes the drill bit directly, while the hammer casing gives straight and stable guidance of the drill bit. This results in minimal deviation and greater hole wall stability, even in fissured or otherwise demanding rock. Since the annulus between the drill pipes and the hole wall is comparatively small, a high flushing velocity is maintained, which contributes further to hole quality. Good hole quality enables the burden and spacing to be increased, which saves time and money. Straight holes make charging easier and enable the amount of explosive to be reduced. The reliable DTH method is an easy way to produce deep, straight holes. From an environmental point of view, the noise emissions and vibration from DTH drilling are comparatively low. This is of particular advantage when drilling in densely populated areas.

Hole diameter: 7 ⁄8" - 5 ½" (22  -140 mm)

Hole diameter: 3 9⁄16" - 6 ½" (90  -165 mm)

Hole diameter: 3 5⁄8" - 9" (90  -229 mm)

Principle: In the simplest of terms, the tophammer drilling method goes back to manually hitting the end of a drill steel with a sledge hammer. As recoil makes the rod jump back it is rotated to ensure that the hole is round. In a similar way the impact energy of the rock drill piston is transmitted to the drill bit in the form of shock waves. Drill cuttings are removed from the hole bottom by air or water flushing.

Principle: The rock drill is situated on the feed beam on the rig and impact energy is imparted from above. Threadless impact rods are stacked inside the threaded drill pipes. The impact rods are used solely to transmit impact energy and feed force, while the drill pipes transmit rotation. COPROD combines the speed of tophammer drilling with the hole straightness of the down-the-hole method.

Principle: The hammer is situated down the hole in direct contact with the drill bit. The hammer piston strikes the drill bit resulting in an efficient transmission of the impact energy and insignificant power losses with the hole depth. The method is widely used for drilling long holes, not only for blasting, but also for water wells, shallow gas and oil wells, and for geo-thermal wells. In mining it is also developed for sampling using the reverse circulation technique (RC drilling).

Blasthole Drilling in Open Pit Mining

DRILLING METHOD GUIDE

The Reverse circulation method

Dual tube reverse circulation (RC) drilling is a method used for collecting rock chips to the surface for subsequent analysis.The air and rock chips are then blown past the bit and up through the centre of the drillstring. to the surface. Normally the air exhausts through a centrifugal classifier so that the rock chips and dust will be captured in a sampler. A sample of the rock chips can be collected in bags. The RC method is used for mineral exploration as an alternative to diamond core drilling. Special RC hammers were developed to improve the productivity and also to reduce the degree of sample contamination. With the RC hammer the cost of drilling is much less than diamond drilling and the penetration rates are an order of magnitude greater than diamond drills. For this reason, may drill campaigns start with reverse circulation drills. When drilling deep holes, below 200 m (660 ft) it is common to use a booster compressor.

Rotary drilling methods

The prime difference from other drilling methods is the absence of percussion. Rotary cutting, using fixed type claw or drag bits, is mainly used for soft rock which is cut by shearing. Rotary crushing uses tricone bits relying on crushing and spalling the rock. This is accomplished by transferring downforce, known as pulldown, to the bit while rotating in order to drive the teeth (commonly tungsten carbide type) into the hole bottom as the three cones rotate around their respective axis. The softer the rock the higher the rotation speed. The drill rigs need to be heavy to provide sufficient weight on bit. Generally, drilling below 152 mm (6 inches) is best accomplished by percussive drilling unless prevailing rock conditions are suited for rotary cutting. Rotary crushing is the prime choice for large diameter holes, above 254 mm (10 inches) in open pit mining, overburden stripping at coal mines, and deep well drilling.

The PARD method

The Percussion Assisted Rotary Drilling system combines percussive power and rotational force. The high frequency impacts provides significant increases in the rate of penetration (ROP), when drilling in medium to hard rock. The Secoroc PARD system consists of a high frequency, low impact energy DTH hammer and a specially designed tricone drill bit that is mounted onto a standard rotary drill and drill string. The system is operating at the conventinal low pressure used for rotary drilling, 50   –100 psi (3.5 –7 bar). The PARD hammer is featuring a leightweight piston with a short stroke, and a unique parallell air flow system, which distributes the air proportionally between the hammer and the tricone bit.

TONS TONS

Hole diameter: 4 15⁄16" - 6 ½" (125  -165 mm)

Hole diameter: 4 3⁄4" - 16" (120 -406 mm)

Hole diameter: 9 7⁄8" - 12¼" (251 -311 mm)

Principle: The hammer is situated down the hole in direct contact with the drill bit similar to the down-thehole method. The difference compared to DTH drilling is that the RC-hammer collected the exhaust air and the rock chips through an inner centre tube of the hammer and inside the drill string up to the surface where samples can be collected in bags. Flushing of the cuttings is done up through the chuck sleeve.

Principle: Rotation is provided by a hydraulic or electric motor driven gearbox, called a rotary head that moves up and down the tower via a feed system, generating the pulldown required to give sufficient weight on the bit. Flushing of drill cuttings between the wall of the hole and the drill rods is normally made with compressed air.

Principle: By combining a low impact DTH hammer with the high feed pressure and torque of rotary tricone drilling, a higher level of energy can be provided for rock drilling, than what a DTH hammer or rotary drilling can create alone. The lightweight hammer piston strikes the tricone drill bit resulting in a transmission of the impact energy to the drillbit. The impact energy from the hammer is supporting the spalling and rock cutting process and is increasing the penetration rate.

Blasthole Drilling in Open Pit Mining 177

Specification guide

Specifications guide From a pure technical point some readers may find the definitions and units used on the following pages confusing. Several of the terms and units have a history dating back to the early days when drilling was based more on practical experience than on advanced engineering.

Feed Force For many users and equipment manufacturers feed force is commonly referred to as “Weight on bit”(WOB), and expressed in lb (pounds) or kg. Since this term WOB is commonly used by many drillers, we decided to include it in the specifications pages. The “Weight on bit” is defined as the downward force on the drill bit, generated by the force from the pulldown cylinders combined with the force generated by the weight of the drill string. From a pure technical point mass and weight are different properties and a force can not be measured in pounds since that is a unit for measurement of mass. Since the 18th century pound-force (lbf) has been used for low precision measurement of a force. A more precise definition is the newton (N), the amount of force required to accelerate a mass of one kilogram at a rate of one meter per second per second. In the specifications tables you will also find the force generated by hydraulic cylinders expressed as Hydraulic pulldown and Hydraulic pullback specified in lbf and kN units.

Conversion table This unit

Times

Equals

Length

This unit

Times

Equals

This unit

Times

Ounce (US fluid oz)

x 29.57

= ml

mph (mile/hour)

x 0.45

Equals

= m/s

x 0.4732

=l

mph (mile/hour)

x 1.61

= km/h

mm (millimeter)

x 0.001 (10-3)

=m

Pint (US liquid)

cm (centimeter)

x 0.01

=m

Quart (US liquid)

x 0.9463

=l

ft/s (foot/second)

x 18.29

= m/min

dm (decimeter)

x 0.1

=m

yd3 (cubic yard)

x 0.7646

= m3

ft/min (foot/minute)

x 0.3048

= m/min

km (kilometer)

x 1 000 (103)

=m

Force

in (inch)

x 25.4

= mm

kN (kilonewton)

x 1 000

=N

blow/min

x 0.017

= Hz

ft (feet)

x 0.305

=m

kp (kilopond)

x 9.81

=N

kHz (kiloHertz)

x 1 000

= Hz

yd (yard)

x 0.914

=m

kgf (kilogram force)

x 9.81

=N

rpm (rev/min)

x 0.01667

= r/s

mile

x 1609

=m

Ibf (pound force)

x 4.45

=N

degree/second

x 0.1667

= r/min

Power

Frequency

Torque (moment of force)

Pressure

J/s (joule/second)

x1

=W

kpm (kilopondmeter)

x 9.81

= Nm

bar

x 100

= kPa

Nm/s (newton meter/second)

x1

=W

Ibf•in (pound-force inch)

x 0.11

= Nm

bar

x 100 000 (105)

= Pa

kW (kilowatt)

x 1 000

=W

Ibf•ft (pound-force foot)

x 1.36

= Nm

kp/cm2

x 0.98

= bar

hk (metric horse power)

x 735.5

=W

Mass (commonly but incorrectly called weight)

atm (atmosphere)

x 1.01

= bar

hp (horsepower UK, US)

x 745.7

=W

g (gram)

psi (pounds/in2)

x 6.895

= kPa

t (tonnes, metric)

x 1 000

= kg

psi

x 0.06895

= bar

l (liter)

x 0.001

= m3

grain

x 0.0648

=g

Area

ml (milliliter)

x 0.001

=l

oz (ounce)

x 28.35

=g

mm2 (square mm)

x 0.000001 (10-6) = m2

dm (cubic decimeter)

x 1.0

=l

ozt (troy ounce)

x 31.10

=g

cm (square cm)

x 0.0001 (10-4)

= m2

cm (cubic decimeter)

x 1.0

= ml

lb (pound)

x 0.4536

= kg

in (square inches)

x 645

= mm2

mm (cubic millimeter)

x 0.001

= ml

ton (long, US)

x 1 016

= kg

ft (square feet)

x 0.0929

= m2

in (cubic inch)

x 16.39

= ml

ton (UK)

x 1 016

= kg

yd (square yard)

x 0.8361

= m2

ft (cubic feet)

x 28.316

=l

ton (short)

x 907

= kg

Acre

x 4 047

= m2

Imperial gallon

x 4.546

=l

Speed (velocity)

Square mile

x 2.590

= km2

US gallon

x 3.785

=l

km/h (kilometer/hour)

x 0.2777

= m/s

ha (hectare)

x 10 000

= m2

Ounce (Imp. fluid oz)

x 28.41

= ml

m/s (meter/sec)

x 3.6

= km/h

Equals

Divided by

This unit

Equals

Divided by

This unit

Equals

Divided by

This unit

Volume

3 3

3

3

3

178

x 0.001

= kg

2

2

2

2

Blasthole Drilling in Open Pit Mining

bLASTHOLE dRILLS

Rotary blasthole drills Atlas Copco offers the most comprehensive line of rotary blasthole drills in the industry. With a multitude of configurations to choose from, you can find the perfect solution for your needs. Many models can be configured for either rotary or DTH drilling, and our blasthole products will drill holes from 4 inches to 16 inches in diameter. On the following pages, you will find basic specifications and brief descriptions of the standard and optional equipment available for each model. The different configurations of drill rigs and drill strings make it possible to find high-performing solutions for a variety of applications. Safety and ergonomic design with operator comfort and well-being in mind, as well as simplicity in maintenance, have been a focus for many years – and are still top priorities. When selecting your drill rig, you may have a choice between high-pressure compressors for DTH drilling or

low-pressure units for rotary drilling, and between diesel or electric power units. Depending on the drilling pattern and bench height, you can select between drills suitable for angle drilling or single- and multi-pass drilling. Some rig models, like the T4BH and the DM series that use conventional control systems, are well known throughout the mining community for their rugged and reliable designs.The newer Pit Viper series, with its more advanced designs, can be equipped with the RCS computerized network control system which offers possibilities for different levels of drill automation and communication. This is only a basic guide. Our product specialists around the world are prepared to provide you with the information you need to select the best drill and drill string package to suit your specific application.

Blasthole Drilling in Open Pit Mining 179

bLASTHOLE dRILLS

180

Blasthole Drilling in Open Pit Mining

bLASTHOLE dRILLS

DM25-SP

Technical data

The Atlas Copco DM25-SP is a crawler mounted, selfpropelled, hydraulic rotary table drive, single-pass rotary drilling rig specifically designed for 4 in. to 6¾ in. (102 mm to 171 mm) blasthole applications to depths of up to 40 ft. (12.2 m) or 50 ft. (15.2 m) of clean hole, depending on tower selection with either rotary or down-the-hole drilling. Feed pressure generates a pulldown force of up to 25,000 lbf (111 kN). The optional angle drilling package allows the tower to be positioned up to a maximum of 15° from the vertical in increments of 5°. All controls for positioning are located at the operator´s control console inside the cab. The package includes a drill pipe support.

Standard equipment

• Spacious, thermal insulated and sound-attenuated cab • Cab pressurizer/heater • Hydraulically retractable dust hood with skirting • Nine quartz halogen night lighting package • Cooling package rated up to 125°F (52°C) ambient temperature • Heavy duty engine silencer/muffler • Separate air intake filters for engine and compressor • Remote hydraulic tower pinning • Hydraulically powered auxiliary chain wrench (Down-the-hole units only) • 230 Gallon (870 Liter) fuel tank • Hydraulic spur gear and planetary drive rotary table with 0 to 170 RPM and a maximum torque of 3,500 lbf•ft • Three 48 in. (1,219 mm) stroke leveling jacks with 18 in. (457 mm) pads • 68,000 lb. (30,845 kg) GVW rated excavator-type undercarriage • 19.7 in. (500 mm) wide triple bar grousers • Separate air intake filters for engine and air compressor • Reinforced rectangular steel track frame with oscillation yoke mounting • Full length kelly bar and kelly sub • Deck service catwalk with railings • Back up alarm

Drilling Method

Rotary or DTH - Single pass

Hole Diameter

4 in - 7 in

102 mm - 178 mm

Hydraulic Pulldown

25,000 lbf

111 kN

Weight on bit

25,000 lb

11,300 kg

Hydraulic Pullback

25,000 lbf

111 kN

Single pass depth

40 ft or 50 ft 12.2 m or 15.2 m

Maximum hole depth

40 ft or 50 ft 12.2 m or 15.2 m

Feed speed

72 ft/min

0.36 m/s

Rotary table, torque

3,500 Ibf•ft

4.7 kNm

Estimated weight

62,000 lb

28 tonnes

Dimensions tower up (50 ft tower) Length

30 ft 6 in

9.3 m

Height

74 ft

22.6 m

Width

12 ft 8 in

3.9 m

Dimensions tower down (50 ft tower) Length

72 ft

21.9 m

Height

13 ft

4.0 m

Compressor range Low pressure, Rotary 900 [email protected] psi 25.4 m3/[email protected] bar High pressure, DTH

900 [email protected] psi 25.4 m3/[email protected] bar

Engine (Tier III) C15

425HP / 317 [email protected] (LP 900)

Cummins

QSX15

425HP / 317 [email protected] (LP 900)

Caterpillar

C15

525HP / 391 [email protected] (HP 900)

Cummins

QSX15

525HP / 391 kW @1800RPM (HP 900)

Caterpillar

Kelly specifications Hole depth*

Kelly diameter

Suggested bit diameters

Thread** size and type

40 ft (12.2 m)

2 7/8"  (73 mm)

4" - 5 1/2"

2 3/8" IF

3 3/4"  (95 mm)

5 1/2" - 7"

2 7/8" API

4 3/4"  (121 mm)

5 7/8" - 7"

3 1/2" API

2 7/8"  (73 mm)

4" - 5 1/2"

2 3/8" IF

3 3/4"  (95 mm)

5 1/2" - 6 1/4"

2 7/8" API

4 3/4"  (121 mm)

5 7/8" - 7"

3 1/2" API

50 ft (15.2 m)

* Clean hole ** All kellys have pin connections on both ends

High pressure DTH drilling Up to 6" DTH hammer and max. 7" bit diameter

DM25

Visit www.atlascopco.com/blastholedrills for more information

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DM30

Technical data

The Atlas Copco DM30 is a crawler mounted, hydraulic tophead drive, muliti-pass rotary drilling rig specifically designed for production blasthole drilling to depths of 90 ft. (27.4 m) with a 30 ft. (9.1 m) drill pipe change. A four-position drill pipe changer is optionally available to achieve drilling depths of 150 ft. (57.7 m). Nominal hole size is 5 in. to 6¾ in. (127 mm to 171 mm). The DM30 generates a bit load force of up to 30,000 lbf (133 kN). The optional angle drilling package allows the tower to be positioned up to a maxuimum of 20º from the vertical in increments of 5º. Designed for quarrying and small mining operations, this versatile drill can be easily loaded onto a trailer and moved from one location to another.

Standard equipment

• Spacious, thermal insulated and sound-attenuated cab • Cab pressurizer/heater/ventilator • Hydraulically raised dust hood with skirting • Nine quartz halogen night lighting package • Auxiliary hoist for drill pipe and accessory handling • Cooling package rated up to 125°F (52°C) ambient • Heavy-duty engine silencer/muffler • Separate air intake filters for engine and air compressor • Remote hydraulic tower pinning • Power indexed carousel for two 4, 4½ , or 5 in. OD x 30 ft. drill rods • Remote hydraulic fork chuck for drill pipe breakout • Hydraulically powered auxiliary chain wrench • 250-gallon (946 l) fuel tank • Rotaryhead with single fixed displacement motor with 0 to 100 RPM available, and a maximum torque of 5,400 lbf•ft • Three 48 in. (1,219 mm) stroke leveling jacks • 68,000 lb. (30,845 kg) GVW rated excavator-type undercarriage • 19.7 in. (500 mm) wide triple bar grousers • Reinforced rectangular steel track frame with oscillation yoke mounting • Deck service catwalk with railings • Back-up alarm

Drilling Method

Rotary or DTH - Multi pass

Hole Diameter

5 in - 6 3/4 in

127 mm - 171 mm

Hydraulic Pulldown

30,000 lbf

133 kN

Weight on bit

30,000 lb

13,600 kg

Hydraulic Pullback

10,000 lbf

44 kN

Single pass depth

26 ft

7.9 m

Maximum hole depth 150 ft

45 m

Feed speed

100 ft/min

0.5 m/s

Rotary head, torque

5,400 Ibf•ft

7.3 kNm

Estimated weight

60,000 lb

28 tonnes

Length

24 ft 4 in

7.4 m

Height

44 ft 4 in

13.5 m

Width

11 ft 10 in

3.6 m

Dimensions tower up

Dimensions tower down Length

42 ft 2 in

12.9 m

Height

14 ft 6 in

4.4 m

Compressor range Low pressure, Rotary

900 [email protected] psi 25.4 m3/[email protected] bar

High pressure, DTH

900 [email protected] psi 25.4 m3/[email protected] bar

Engine (Tier III) Caterpillar

C15

425HP / 317 [email protected] (LP 900)

Cummins

QSX15

425HP / 317 [email protected] (LP 900)

Caterpillar

C15

525HP / 391 [email protected] (HP 900)

Cummins

QSX15

525HP / 391 [email protected] (HP 900)

Drill pipe specification: 30 ft (9.1m) Drill pipe diameter

Suggested bit diameters - rotary

Thread

4" (102 mm)

5" – 6"

2 7/8" API

4 ½" (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5" (127 mm)

6 3/4"

3 1/2" API or BECO

High pressure DTH drilling Up to 6" DTH hammer and max. 6 ¾" bit diameter

DM30

Visit www.atlascopco.com/blastholedrills for more information

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DM30 II The Atlas Copco DM30 II is an improved and upgraded version of the DM30. It is a crawler mounted, hydraulic tophead drive, muliti-pass rotary drilling rig specifically designed for production blasthole drilling to depths of 90 ft. (27.4 m) with a 30 ft. (9.1 m) drill pipe change. A four-position drill pipe changer is optionally available to achieve drilling depths of 150 ft. (45.7 m). Nominal hole size is 5 in. to 7-7/8 in. (127 mm to 200 mm). The DM30 II generates a bit load force of up to 30,000 lbf (133 kN). The optional angle drilling package allows the tower to be positioned up to a maxuimum of 30° from the vertical in increments of 5°. Designed for quarrying and small mining operations, this versatile drill can be easily loaded onto a trailer and moved from one location to another.

Major upgrades • • • • • • • • • •

New larger, thermal insulated cabin mounted on the right side of the carrier(seen from the drill end) Electric over hydraulic control system, similar to what is used on other rigs in the DM-series Optional walk way and enlarged deck area for improved access to service and maintenance. Improved optional angle drilling package, allows the tower to be positioned up to a maximum of 30º from the vertical in increments of 5º New long life main frame designed with I-beams, featuring oscillation yoke mounting. Enlarged hydraulically raised dust hood with skirting provide more space for cuttings. New design with hydraulic motor for carousel indexing. Optional Atlas Copco screw type low and high pressure compressor, with high air temperature shut down. New 14 section directional valve system. Standard central lubrication manifold

Standard equipment

• Cab pressurizer/heater/ventilator • Eleven quartz halogen night lighting package6 • Auxiliary hoist for drill pipe and accessory handling • Cooling package rated up to 125°F (52°C) ambient • Heavy-duty engine silencer/muffler • Separate air intake filters for engine and air compressor • Remote hydraulic tower pinning • Hydraulic indexed carousel for two 4½, 5 or 5-½ in. OD x 30 ft. drill rods • Remote hydraulic fork chuck for drill pipe breakout • Hydraulically powered auxiliary chain wrench • 230-gallon (870 l) fuel tank • Rotary head with single fixed or variable displacement motor with 0 to 160 RPM available, and a maximum torque of 5,400 lbf•ft • Three 48 in. (1,219 mm) stroke leveling jacks • 77,000 lb. (34,650 kg) GVW rated excavator-type undercarriage • 19.7 in. (500 mm) wide triple bar grousers • Reinforced rectangular steel track frame with oscillation yoke mounting • Deck service catwalk with railings • Back-up alarm

Technical data Drilling Method

Drilling Method DTH - Multi pass

Hole Diameter

5 in - 6 3/4 in

127 mm - 171 mm

Hydraulic Pulldown

30,000 lbf

133 kN

Drilling Method

Rotary - Multi pass

Hole Diameter

5 in - 7 7/8 in

127 mm - 200 mm

Hydraulic Pulldown

30,000 lbf

133 kN

Weight on bit

30,000 lb

13,600 kg

Hydraulic Pullback

10,000 lbf

44 kN

Single pass depth

26 ft

7.9 m

Maximum hole depth

150 ft

45 m

Feed speed

100 ft/min

0.5 m/s

Rotary head, torque

5,400 Ibf•ft

7.3 kNm

Estimated weight

70,000 lb

31.5 tonnes

Dimensions tower up Length

28 ft 7 in

8.7 m

Height

45 ft 2 in

13.8 m

Width

16 ft 11 in

5.2 m

Dimensions tower down Length

44 ft 11 in

13.7 m

Height

16 ft 8 in

5.1 m

Compressor range Low pressure

Rotary 1050 [email protected] psi 29.7 m3/[email protected] bar

High pressure

DTH 900 [email protected] psi 25.4 m3/[email protected] bar

Engine (Tier III) Caterpillar

C15

475HP / 354 [email protected] (LP 1050)

Caterpillar

C15

525HP / 391 [email protected] (HP 900)

Drill Pipe specification: 30 ft (9.1m) Drill pipe diameter

Suggested bit diameters rotary

Thread

4 1/2" (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5" (127 mm)

6 3/4"

3 1/2" API or BECO

5 1/2" (140 mm)

7 7/8"

3 1/2" BECO

High pressure DTH drilling Up to 6" DTH hammer and max. 6 3/4" bit diameter

Visit www.atlascopco.com/blastholedrills for more information

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T4BH

Technical data

The Atlas Copco T4BH is synonymous with mobility, power, performance, and productivity. Mounted on a custom carrier, the T4BH is designed to perform in rough terrain and has been the leading blasthole drill in its class in the quarry and mining industries for over 35 years. The T4BH is a truck mounted, hydraulic tophead drive, multipass rotary drilling rig specifically designed for production blasthole drilling to depths of 150 ft. (45.7 m) with a 25 ft. (7.6 m) drill pipe change. An optional 30 ft (9.1m) tower is also available with the 8 x 4 carrier option.

Standard equipment

• • • • • • • • • • • • • • • •

Spacious, thermal insulated sound-attenuated cab Six quartz halogen night lighting package Rectangular dust hood with skirting Auxiliary hoist for drill pipe and accessory handling Cooling package rated up to 125°F (52°C) ambient Heavy-duty engine silencer/muffler Separate air intake filters for engine and air compressor Power indexed carousel for five 4 ½ in OD x 25 ft pipe Remote hydraulic fork chuck for drill pipe breakout Hydraulically powered auxiliary chain wrench 225 Gallon (851 Liter) Fuel tank 4SV-2-10 spur gear 2-motor rotary tophead with 0 to 160 RPM, and maximum torque 6,500 lbf•ft Three 48 in. (1,219 mm) stroke leveling jacks Custom designed 3-axle carrier with 380 hp (283 kW) diesel engine, 10-speed transmission and 16 in. (406 mm) wide flange H-beam frame Remote tower pinning Back-up alarm

Drilling Method

DTH or Rotary - Multi pass

Hole Diameter

5 5/8 in - 9 7/8 in

143 mm - 251 mm

Hydraulic Pulldown

30,000 lbf

133 kN

Weight on bit

30,000 lb

13,600 kg

Hydraulic Pullback

22,000 lbf

97 kN

Single pass depth

22 ft 6 in or 27 ft 6 in

6.8 m or 8.4 m

Maximum hole depth*

147 ft 6 in or 177 ft 6 in

45 m or 54.1 m

Feed speed

60 ft/min

0.3 m/s

Rotary head, torque

6,000 Ibf•ft 7,165 Ibf•ft

8.8 kNm 9.7 kNm

Estimated weight

58,000 lb

26 tonnes

Dimensions tower up (25 ft tower) Length

28 ft 8 in

8.1 m

Height

36 ft 6 in

11.1 m

Width

8 ft

2.4 m

Dimensions tower down (25 ft tower) Length

35 ft 0 in

10.7 m

Height

13 ft 6 in

4.1 m

Compressor range High pressure, DTH

900 [email protected] psi 25.4 m3/[email protected] bar

High pressure, DTH

1070 [email protected] psi 30.3 m3/[email protected] bar

High pressure, DTH

1250 [email protected] psi 35.4 m3/[email protected] bar

Engine ( TierII, Tier III) 2

3

Cummins

QSX153

525HP / 391 [email protected] (HP 900)

Cummins

QSX15

600HP / 447 [email protected] (HP 1070)

Cummins

QSK19C2

3

760HP / 567 [email protected] (HP 1250)

Drill pipe specification: 25 ft (7.6 m) Drill pipe diameter

Suggested bit diameters Thread

4"  (102 mm)

5 5/8" – 6"

2 7/8" API

4 1/2"  (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5"  (127 mm)

6 3/4" – 7 3/8"

3 1/2" API or BECO

5 1/2"  (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4"  (159 mm)

7 7/8" – 9"

4" BECO

7"  (178 mm)

9"-9 7/8"

4 1/2" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 9 7/8" bit diameter * Maximum hole depth only achieved with certain pipe sizes and wall thicknesses

T4BH

Visit www.atlascopco.com/blastholedrills for more information

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DM45/DM50 The Atlas Copco DM45 and DM50 are crawler mounted, hydraulic tophead drive, multi-pass rotary drilling rigs specifically designed for production rotary or DTH blasthole drilling to depths of 175 ft. (53.3 m) with a 30 ft. (9.1 m) drill pipe change.

Standard equipment

• • • • • • • • • • • • • • • • • • • • • •

Insulated cab with FOPS 80 dB(A) Cab pressurizer / ventilator / heater Nine quartz halogen night lighting package Dust hood with curtains and hydraulically raising dust flap Auxiliary hoist for drill pipe and accessory handling Heavy-duty engine silencer/muffler Separate air intake filters with quick release dust drop covers for engine and air compressor Gear indexing carousel for five 4½ in. x 30 ft. pipe Sliding hydraulic fork wrench for drill pipe breakout Hydraulically powered auxiliary chain wrench 350-gallon (1,324 L) fuel tank 4SV-2-10 two motor high speed rotary head with spline lubrication, 0 to 160 RPM, and a maximum torque 7,200 lbf•ft 30 foot drill pipe change No-bump rod changer Ether injection Jack-up indicator lights Three 48 in. (1,219 mm) stroke leveling jacks 23.6 in. (600 mm) wide triple bar grousers Reinforced rectangular steel track frame with oscillation yoke Walkways and railings Remote tower pinning Back-up alarm

Technical data Drilling Method

Rotary or DTH Multi pass

Hole Diameter

5 7/8 in - 9 in

149 mm - 229 mm

Hydraulic Pulldown

45,000 lbf

200 kN

Weight on bit

45,000 lb

20,400 kg

Hydraulic Pullback

22,000 lbf

98 kN

Single pass depth

27 ft 5 in

Maximum hole depth* 175 ft Feed speed

8.5 m 53.3 m

146 ft/min Ibf•ft

0.7 m/s

Rotary head, torque

7,200

Estimated weight

77,000 lb 95,000 lb

35 tonnes 41 tonnes

Length

31 ft 10 in

9.7 m

Height

43 ft 7 in

13.3 m

Width

17 ft 2 in

5.23 m

9,76 kNm

Dimensions tower up

Dimensions tower down Length

43 ft 7 in

13.3 m

Height

18 ft

5.5 m

Compressor range Low pressure, Rotary 900 [email protected] psi 25.4 m3/[email protected] bar Low pressure, Rotary 1050 [email protected] psi 29.7 m3/[email protected] bar Low pressure, Rotary 1200 [email protected] psi 34.0 m3/[email protected] bar High pressure, DTH

900 [email protected] psi 25.4 m3/[email protected] bar

High pressure, DTH

1070 [email protected] psi 30.3 m3/[email protected] bar

Engine (Tier III) Caterpillar

C15

440HP / 328 [email protected] (LP 900)

Cummins

QSX15

425HP / 317 [email protected] (LP 900)

Caterpillar

C15

475HP / 354 [email protected] (LP 1050)

Cummins

QSX15

475HP / 354 [email protected] (LP 1050)

Caterpillar

C15

540HP / 403 [email protected] (LP 1200)

Cummins

QSX15

530HP / 395 [email protected] (LP 1200)

Caterpillar

C15

540HP / 403 [email protected] (HP 900)

Cummins

QSX15

530HP / 395 [email protected] (HP 900)

Caterpillar

C18

630HP / 470 [email protected] (HP 1070)

Cummins

QSX15

600HP / 447 [email protected] (HP 1070)

Drill pipe specification: 30 ft (9.1 m) Drill pipe diameter

Suggested bit diameters

Thread

4 1/2"  (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5"  (127 mm)

6 3/4" – 7 3/8"

3 1/2" API or BECO

5 1/2"  (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4"  (159 mm)

7 7/8" – 9"

4" BECO

7"  (178 mm)

9"

4 1/2" BECO

High pressure DTH drilling (DM45) Up to 6 1/2" DTH hammer and max. 8" bit diameter DM45

* Maximum hole depth only achieved with certain pipe sizes and wall thicknesses

Visit www.atlascopco.com/blastholedrills for more information

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DML-SP The Atlas Copco DML-SP is a crawler-mounted, hydraulic table drive, single-pass rotary drilling rig, specifically designed for production blasthole drilling to depths of up to 60 ft. (18.3 m) in a single pass without a drill pipe change. Nominal hole size range is 6 to 9-7/8 in. (152 to 251 mm) for rotary bit applications. The DML-SP has the option for a 50 ft (15.2 m) clean hole tower or a 60 ft (18.3 m) clean hole tower.

Standard equipment

• Insulated cab with FOPS • Cab pressurizer/heater • Nine-quartz, halogen night lighting package • Rectangular dust hood with skirting and hydraulically retractable front curtain • Cooler package rated up to 125°F (52°C) ambient temperature • Heavy duty engine silencer/muffler • Separate air intake filters with quick release dust drop covers for engine and air compressor • Hydraulically powered auxiliary chain wrench • 350-gallon (1,324 l) fuel capacity • Single motor rotary table with variable hydraulic motor (0-100 RPM) and a maximum torque of 7,500 lbf•ft • Hydrostatic motor feed system • Three 48 in. (121.9 cm) stroke leveling jacks • 31.5 in. (800 mm) wide triple bar grousers • Reinforced rectangular steel track frame with oscillation yoke mounting • Walkways and deck railings • Full depth kelly bar • Kelly RPM tachometer on console • Remote tower pinning • Back-up Alarm • Ether injection • Jack-up indicator lights

Technical data Drilling Method

Rotary or DTH - Single pass

Hole Diameter

6 in - 9 7/8 in

152 mm - 251 mm

Hydraulic Pulldown

54,000 lbf

240 kN

Weight on bit

54,000 lb

24,500 kg

Hydraulic Pullback

54,000 lbf

240 kN

Single pass depth

50 ft or 60 ft

15.2 m or    18.3 m

Maximum hole depth

50 ft or 60 ft

15.2 m or    18.3 m

Feed speed

100 ft/min

0.5 m/s

Rotary table, torque

7,500 Ibf•ft

10.2 kNm

Estimated weight

90,000 -100,000 lb

41 - 45 tonnes

Length (50 ft tower)

37 ft 6 in

11.4 m

Length (60 ft tower)

37 ft 6 in

11.4 m

Height (50 ft tower)

71 ft 7 in

21.8 m

Height (60 ft tower)

82 ft 7 in

25.2 m

Width

13 ft 10 in

4.1 m

Dimensions tower up

Dimensions tower down Length (50 ft tower)

68 ft

20.7 m

Length (60 ft tower)

79 ft

24.1 m

Height (50 ft tower)

19 ft 7 in

6.0 m

Height (60 ft tower)

19 ft 7 in

6.0 m

Compressor range Low pressure rotary

1,200 [email protected] / 34.0 m3/[email protected] bar

Low pressure rotary

1,600 [email protected]psi / 45.0 m3/[email protected] bar

Low pressure rotary

1,900 [email protected] / 53.8 m3/[email protected] bar

High pressure, DTH

1,250 [email protected] / 35.4 m3/[email protected] bar

Engine (2  TierII, 3  Tier III) 525HP / 391 [email protected] (LP 1200)

Caterpillar C153 Cummins

QSX15

3

Cummins

QSX153

QSK19

2

755HP / 563 [email protected] (LP 1900)

2

800HP / 597 [email protected] (HP 1250)

QSK19C2

760HP / 567 [email protected] (HP 1250)

Caterpillar C27 Cummins

600HP / 447 [email protected] (LP 1600) 800HP / 597 [email protected] (LP 1900)

Caterpillar C27

2

Cummins

525HP / 391 [email protected] (LP 1200) 630HP / 470 [email protected] (LP 1600)

Caterpillar C183

Kelly specifications Hole depth*

Kelly diameter

Suggested bit diameters

50 ft. (15.2 m) or 60 ft. (18.3 m)

4 3/4 in. (121 mm) 6" – 6 3/4"

3 1/2 in. Reg.

6 1/4 in. (159 mm) 7 7/8" – 9"

4 1/2 in. Reg.

7 in. (178 mm)

5 1/2 in. Reg.

9" – 9 7/8"

Thread** size and type

* Clean hole ** All kellys have pin connections on both ends.

High pressure DTH drilling Up to 8" DTH hammer and max. 8 7/8" bit diameter

Visit www.atlascopco.com/blastholedrills for more information

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DML

Technical data Drilling Method

Rotary or DTH - Multi pass

The Atlas Copco DML is a crawler mounted, hydraulic tophead drive, multi-pass rotary drilling rig specifically designed for production blasthole drilling to depths of 175 ft. (53.3 m) with a 30 ft. (9.1 m) drill pipe change. An optional 35-ft. (10.7 m) steel change is also available to handle single pass drilling requirements. Various carousel capacities are also available for the 35-ft. (10.7 m) option.

Hole Diameter

5 7/8 in - 10 5/8 in

149 mm - 270 mm

Hydraulic Pulldown

60,000 lbf

267 kN

Weight on bit

60,000 lb

27,200 kg

Hydraulic Pullback

22,000 lbf

98 kN

Single pass depth

27 ft 5 in or 32 ft 5 in 8.5 m or 10 m

Maximum hole depth*

175 ft or 205 ft

Standard equipment

Feed speed

146 ft/min

0.7 m/s

Rotary head, torque

7,200 Ibf•ft

9.76 kNm

Estimated weight

87,000 - 110,000 lb

39.5 - 50 tonnes

• Insulated cab with FOPS • Cab pressurizer / ventilator / heater • Nine quartz halogen night lighting package • Dust hood with curtains and hydraulically raising dust flap • Auxiliary hoist for drill pipe and accessory handling • Heavy-duty engine silencer/muffler • Separate air intake filters with quick release dust drop covers for engine and air compressor • Gear indexing carousel • Sliding hydraulic fork wrench for drill pipe breakout • Hydraulically powered auxiliary chain wrench • 350-gallon (1,324 L) fuel tank • 4SV-2-10 two motor high speed rotary head with spline lubrication, 0 to 160 RPM, and a maximum torque of 7,200 lbf•ft • 30 foot drill pipe change • No-bump rod changer • Ether injection • Jack-up indicator lights • Three 48 in. (1,219 mm) stroke leveling jacks • 33.5 in. (850 mm) wide triple bar grousers • Reinforced rectangular steel track frame with oscillation yoke • Walkways and railings • Remote tower pinning • Back-up alarm

53.3 m or 62.5 m

Dimensions tower up (30 ft tower) Length

31 ft 10 in

9.7 m

Height

43 ft 8 in

13.3 m

Width

16 ft 6 in

5m

Dimensions tower down (30 ft tower) Length

43 ft 7 in

13.3 m

Height

17 ft 8 in

5.4 m

Compressor range Low pressure rotary

1,200 [email protected] psi / 34.0 m3/[email protected] bar

Low pressure rotary

1,600 [email protected] psi / 45.0 m3/[email protected] bar

Low pressure rotary

1,900 [email protected] psi / 53.8 m3/[email protected] bar

High pressure, DTH (electric motor)

1,050 [email protected] psi / 29.8 m3/[email protected] bar

High pressure, DTH

1,250 [email protected] psi / 35.4 m3/[email protected] bar

High pressure, DTH

1,450 [email protected] psi / 41 m3/[email protected] bar

Engine (2Tier II, 3Tier III ) Caterpillar

C153

540HP / 403 [email protected] (LP 1200)

Cummins

QSX153

530HP / 395 [email protected] (LP 1200)

Caterpillar

C183

630HP / 470 [email protected] (LP 1600)

Cummins

QSX15

600HP / 447 [email protected] (LP 1600)

Caterpillar

C272

800HP / 597 [email protected] (LP 1900)

Cummins

QSK192

755HP / 563 [email protected] (LP 1900)

Caterpillar

2

C27

800HP / 597 [email protected] (HP 1250)

Cummins

QSK19C2

755HP / 563 [email protected] (HP 1250)

Caterpillar

C272

800HP / 597 [email protected] (HP 1450)

Weg motor

6808

700HP / 522 [email protected] – 60Hz (LP 1200 or HP1050)

3

Drill pipe specification 30 ft (9.1 m) or 35 ft (10.7 m) Drill pipe diameter

Suggested bit diameters

Thread

4 1/2"  (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5"  (127 mm)

6 3/4" – 7 3/8"

3 1/2" API or BECO

5 1/2"  (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4"  (159 mm)

7 7/8" – 9"

4" BECO

7"  (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8"  (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 8 7/8" bit diameter * Maximum hole depth only achieved with certain pipe sizes and wall thicknesses

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper PV-235

Technical data Drilling Method

Rotary or DTH - Multi pass

The Pit Viper series 235 blasthole drills offers several advanced options, like the RCS control system, remote tramming, auto levelling, and GPS navigation. The hydraulic system has been refined with load sensing and other features to reduce horsepower demand. There are several engine and compressor combinations available for either rotary or high pressure DTH drilling. The PV-235 can be supplied with two towers - to drill 35 ft (10.7 m) or 40 ft (12.2 m) clean holes up to 10 5⁄8" (270 mm) in diameter.

Hole Diameter

6 in - 10 5/8 in

152 mm - 270 mm

Hydraulic Pulldown

60,000 lbf

267 kN

Weight on bit

65,000 lb

29,500 kg

Hydraulic Pullback

27,000 lbf

120 kN

Single pass depth

40, 35 ft

12.2, 10.7 m

Maximum hole depth*

240, 210 ft

73.2, 64.0 m

Feed speed

140 - 193 ft/min

0.7 - 1.0 m/s

Rotary head, torque

4,900 Ibf•ft 8,200 Ibf•ft

6.6 kNm 11.1 kNm

Standard equipment

Estimated weight

135,000 lb

61 tonnes

• RCS Rig Control System, computerized network • Spacious thermal insulated cab with FOPS and noise abated less than 80 dB(A) • Cab pressurizer / ventilator / heater • Twelve quartz halogen night lighting package • Dust hood with curtains and hydraulically raising dust flap • Auxiliary hoist for drill pipe and accessory handling • Heavy duty engine silencer / muffler • Separate air intake filters with rubber dust evacuator for engine and air compressors • Gear indexing carousel for 5 ½ in pipe • Sliding hydraulic fork wrench for drill pipe breakout • Hydraulically powered auxiliary breakout wrench • 450 gallon fuel tank (1,700 l) • 4SV-2-10 two speed spur gear rotary head with spline lubrication, 0-180 RPM, and a maximum torque of 8,200 lbf•ft • 35 ft drill pipe changer • No-bump rod changer • Ground level battery and starter lockable master-switches with jump start receptacle • Jack-up indicator lights • Four 48 in (1.2 m) stroke leveling jacks • Triple bar grousers 33.5 in (850 mm) wide • Reinforced rectangular steel track frame with oscillation yoke • Walkways and railings • Remote tower pinning • Back-up alarm

Dimensions tower up (40 ft tower) Length

34 ft 2 in

10.4 m

Height

62 ft 6 in

19 m

Width

17 ft 4 in

5.3 m

Dimensions tower down (40 ft tower) Length

63 ft 5 in

19.3 m

Height

20 ft 4 in

6.4 m

Compressor range Low pressure rotary

1,600 [email protected] psi / 45.0 m3/[email protected] bar

Low pressure rotary

1,900 [email protected] psi / 53.8 m3/[email protected] bar

High pressure, DTH

1,250 [email protected] psi / 35.4 m3/[email protected] bar

High pressure, DTH

1,450 [email protected] psi / 41.0 m3/[email protected] bar

High pressure, DTH (electric motor)

1,250 [email protected] psi / 35.4 m3/[email protected] bar

High pressure, DTH

1,300 [email protected] psi / 37.6 m3/[email protected] bar

Engine ( Tier III, Tier II) 3

2

630HP / 470 [email protected] (LP 1600)

Caterpillar

C183

Cummins

QSX15

Caterpillar

C272

800HP / 597 [email protected] (LP 1900 or HP 1250)

Cummins

QSK192

755HP / 563 [email protected] (LP 1900 or HP 1250)

Caterpillar

C272

800HP / 597 [email protected] (HP 1450)

WEG

6808

800HP / 597 [email protected] Hz

3

600HP / 447 [email protected] (LP 1600)

Drill pipe specification: 35 ft (10.7 m) or 40 ft (12.2 m) Drill pipe diameter

Suggested bit diameters

Thread

4 1/2"  (114 mm)

6" – 6 3/4"

3" BECO

5"  (127 mm)

6 3/4" - 7 3/8"

3 1/2" BECO

5 1/2"  (140 mm)

6 3/4" - 7 7/8"

3 1/2" BECO

6 1/4" (159 mm)

7 7/8" - 9"

4" BECO

7"  (178 mm)

9"

4 1/2" BECO

7 5/8"  (194 mm)

9 7/8"

5 1/4" BECO

8"  (203 mm)

9 7/8" - 10 5/8"

5 1/4" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 8 7/8" bit diameter PV-235

* Maximum hole depth only achieved with certain pipe sizes and wall thicknesses

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper PV-271

Technical data

The PV-271 is designed to handle 6-¼" up to 8- ⁄ " drill rods. The cable feed system utilizes a dual rod/dual piston cylinder and offers high feed speeds for increased productivity. The PV-271 offers a 55 ft single-pass tower with a total depth capacity of 105 ft through a 2-rod carousel with 25 ft rods. It has an option to be delivered with the RCS Computerized rig control system and a new fully integrated cabin, incorporating functions like; remote tramming, auto levelling, auto drilling, and GPS navigation. 58

Standard equipment • Insulated, pressurized, air conditioned cab with tinted glass and suspension operator seat • Caterpillar 345XL undercarriage with hydraulic track tensioners • Hydraulic cylinders driven cable feed system • Hydraulic motor driven rotary head with spline lubrication, maximum 8,700 lbf•ft torque; speed range 0 - 150 rpm • Rotary head tachometer on operator console • Remote hydraulic tower pinning • Two-rod carousel for 6 ¼" to 8- 5⁄8" drill rods • "No-bump" rod changer • Hydraulically powered breakout wrench (fork chuck) • Hands Free auxiliary hydraulic chain wrench • 8,000 lb (3,629 kg) capacity auxiliary hoist • Hydraulically retractable dust curtains • Cooling package • Separate air intake filters for engine and air compressor • Wide flange structural steel beam frame with oscillation yoke mounting • Hydraulic Test Station • 13-light night lighting package-70 watt halogen • Full deck service catwalks and railings • Two 48" (1.2 m) and one 60" (1.52 m) stroke leveling jacks

Drilling Method

Rotary or DTH – Single pass

Hole Diameter

6 3/4 in - 10 5/8 in

171 mm - 270 mm

Hydraulic Pulldown

70,000 lbf

311 kN

Weight on bit

75,000 lb

34,000 kg

Hydraulic Pullback

35,000 lbf

156 kN

Single pass depth

55 ft*

16.8 m*

Maximum hole depth

105 ft

32 m

Feed speed

127 ft/min

0.6 m/s

Rotary head, torque

8,700 Ibf•ft

11.8 kNm

Estimated weight

185,000 lb

84 tonnes

Length

41 ft 3 in

12.6 m

Height

87 ft

26.5 m

Width

18 ft 4 in

5.6 m

Dimensions tower up

Dimensions tower down Length

83 ft 7 in

25.5 m

Height

22 ft 1 in

6.7 m

Compressor range Low pressure rotary

1,900 [email protected] psi / 53.8 m3/[email protected] bar

Low pressure rotary

2,600 [email protected] psi / 73.6 m3/[email protected] bar

High pressure, DTH

1,450 [email protected] psi / 41.1 m3/[email protected] bar

Engine (Tier ll) Caterpillar

C27

800HP / 597 [email protected] (LP 1900)

Cummins

QSK19

755HP / 563 [email protected] (LP 1900)

Caterpillar

C32

950HP / 708 [email protected] (LP 2600)

Caterpillar

C27

800HP / 597 [email protected] (HP 1450)

Weg motor

6808

700HP / 521 [email protected] 50 or 60Hz

Weg motor

6811

900HP / 671 [email protected] 50 or 60Hz

Drill pipe specification: 25 ft (7.6 m) Drill pipe diameter

Suggested bit diameters

Thread

6 1/4"  (159 mm)

6 3/4" – 9"

4" BECO

7"  (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8"  (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8"  (203 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8 5/8"  (219 mm)

10 5/8"

6" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 9 7/8" bit diameter * There is also a 65 ft (19.8 m) clean hole tower option (see page 76 - 77)

PV-271

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper 271 RCS The PV-271 Rig Control System (RCS) is designed to handle 6-¼" to 8-5⁄8" drill rods. The cable feed system utilizes a dual rod/dual piston cylinder and offers high feed speeds for increased productivity. The PV-271 RCS offers a 55 ft single-pass tower with a total depth capacity of 105 ft through a 2-rod carousel with 25 ft rods. This version of the machine comes standard with a new cab that fully integrates the RCS with the option to fully incorporate the following functions: wireless remote tramming, auto leveling, auto drilling, and GPS navigation.

Standard equipment • Spacious thermal insulated cab with FOPS and noise abatement to less than 70 dB(A) • Excavator style chair and controls for increased comfort and visibility • Standard Cab pressurizer/ventilator/heater with the option to upgrade the pressurizer • Caterpillar 345XL undercarriage with hydraulic track tensioners • Hydraulic cylinders-driven cable feed system • Hydraulic motor driven rotary head with spline lubrication, maximum 8,700 lbf-ft torque; speed range 0 – 150 rpm • Rotary Head tachometer integrated into the RCS system • Remote hydraulic tower pinning • Two-rod carousel for 6-¼" to 8-5⁄8" drill rods • “No Bump” rod changer • Hydraulically powered breakout wrench (fork chuck) • Hands-free auxiliary hydraulic chain wrench • 8,000 lb (3,629 kg) capacity auxiliary hoist • Hydraulically retractable dust curtains • Cooling package • Separate air intake filters for engine and air compressor • Wide flange structural steel beam frame with oscillation yoke mounting • 14-light night lighting package – 70 watt halogen • Full deck service catwalks and railings • Two 48" (1.2 m) and one 60" (1.52 m) stroke leveling jacks • 350 US gallon (1,325 L) fuel tank w/option to upgrade to larger tanks.

Technical data Drilling Method

Rotary or DTH – Single pass

Hole Diameter

6 3/4 in - 10 5/8 in

171 mm - 270 mm

Hydraulic Pulldown

70,000 lbf

311 kN

Weight on bit

75,000 lb

34,000 kg

Hydraulic Pullback

35,000 lbf

156 kN

Single pass depth

55 ft*

16.8 m*

Maximum hole depth

105 ft

32 m

Feed speed

127 ft/min

0.6 m/s

Rotary head, torque

8,700 Ibf•ft

11.8 kNm

Estimated weight

185,000 lb

84 tonnes

Length

54 ft

16.4 m

Height

87 ft

26.5 m

Width

23 ft 8 in

7.2 m

Dimensions tower up

Dimensions tower down Length

86 ft 4 in

26.3 m

Height

23 ft 3 in

7.0 m

Compressor range Low pressure rotary

1,900 [email protected] psi / 53.8 m3/[email protected] bar

Low pressure rotary

2,600 [email protected] psi / 73.6 m3/[email protected] bar

High pressure, DTH

1,450 [email protected] psi / 41.1 m3/[email protected] bar

Engine (Tier ll) Caterpillar

C27

800HP / 597 [email protected] (LP 1900)

Cummins

QSK19

755HP / 563 [email protected] (LP 1900)

Caterpillar

C32

950HP / 708 [email protected] (LP 2600)

Caterpillar

C27

800HP / 597 [email protected] (HP 1450)

Weg motor

6808

700HP / 521 [email protected] 50 or 60Hz

Weg motor

6811

900HP / 671 [email protected] 50 or 60Hz

Drill pipe specification: 25 ft (7.6 m) Drill pipe diameter

Suggested bit diameters

Thread

6 1/4"  (159 mm)

6 3/4" – 9"

4" BECO

7"  (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8"  (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8"  (203 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8 5/8"  (219 mm)

10 5/8"

6" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 9 7/8" bit diameter * There is also a 65 ft (19.8 m) clean hole tower option (see page 76 - 77)

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper PV-275

Technical data

The PV-275 is designed to handle 6-¼" up to 8- ⁄ " drill rods. The cable feed system utilizes a dual rod/dual piston cylinder and offers high feed speeds for increased productivity. The PV-275 offers a multi-pass tower with 195-ft depth capacity through a 4-rod carousel with 40-ft rods. It has an option to be delivered with the RCS Computerized rig control system and a new fully integrated cabin, incorporating functions like; remote tramming, auto levelling, auto drilling, and GPS navigation. 58

Standard equipment • Insulated, pressurized, air conditioned cab with tinted glass and suspension operator seat • Caterpillar 345SL undercarriage with hydraulic track tensioners • Hydraulic cylinders driven cable feed system • Hydraulic motor driven rotary head with spline lubrication, maximum 8,700 lbf•ft (11,800 Nm) torque; speed range 0 – 150 rpm • Rotary head tachometer on operator console • Remote hydraulic tower pinning • Four-rod carousel for 6 ¼" to 8-5⁄8" drill rods • "No-bump" rod changer • Hydraulically powered breakout wrench (fork chuck) • Hands Free auxiliary hydraulic wrench • 8,000 lb (3,629 kg) capacity auxiliary hoist • Hydraulically retractable dust curtains • Hydraulic Test Station • Two 48" (1.2 m) and one 60" (1.52 m) stroke leveling jacks • Cooling package • 350 U.S. gallon (1,325 L) fuel tank w/option to upgrade to larger tanks • Separate air intake filters for engine and air compressor • Wide flange structural steel beam frame with oscillation yoke mounting • 12-light night lighting package- 70 watt halogen • Full deck service catwalks and railings

Drilling Method

Rotary or DTH – Multi pass

Hole Diameter

6 3/4 in - 10 5/8 in

171 mm - 270 mm

Hydraulic Pulldown

70,000 lbf

311 kN

Weight on bit

75,000 lb

34,000 kg

Hydraulic Pullback

35,000 lbf

156 kN

Single pass depth

37 ft

11.3 m

Maximum hole depth

195 ft

59.4 m

Feed speed

127 ft/min

0.6 m/s

Rotary head, torque

8,700 Ibf•ft

11.8 kNm

Estimated weight

185,000 lb

84 tonnes

Length

41 ft 6 in

12.6 m

Height

67 ft

20.4 m

Width

18 ft 4 in

5.6 m

Dimensions tower up

Dimensions tower down Length

63 ft 6 in

19.4 m

Height

22 ft 1 in

6.7 m

Compressor range Low pressure rotary

1,900 [email protected] psi / 53.8 m3/[email protected] bar

Low pressure rotary

2,600 [email protected] psi / 73.6 m3/[email protected] bar

High pressure, DTH

1,450 [email protected] psi / 41.1 m3/[email protected] bar

Engine (Tier ll) Caterpillar

C27

800HP / 597 [email protected] (LP 1900)

Cummins

QSK19

755HP / 563 [email protected] (LP 1900)

Caterpillar

C32

950HP / 708 [email protected] (LP 2600)

Caterpillar

C27

800HP / 597 [email protected] (HP 1450)

Weg motor

6808

700HP / 521 [email protected] 50 or 60Hz

Weg motor

6811

900HP / 671 [email protected] 50 or 60Hz

Drill pipe specification: 40 ft (12.2 m) Drill pipe diameter

Suggested bit diameters

Thread

6 1/4"  (159 mm)

6 3/4" – 9"

4" BECO

7"  (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8"  (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8"  (203 mm)

9 7/8" – 11"

5 1/4" BECO

8 5/8"  (219 mm)

10 5/8"

6" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 9 7/8" bit diameter

PV-275

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper 275 RCS The PV-275 Rig Control System (RCS) is designed to handle 6-¼" up to 8-5⁄8"drill rods. The cable feed system utilizes a dual rod/dual piston cylinder and offers high feed speeds for increased productivity. The PV-275 RCS offers a multi-pass tower with a total depth capacity of 195 ft through a 4-rod carousel with 40 ft rods. This version of the machine comes standard with a new cab that fully integrates the RCS with the option to fully incorporate the following functions: wireless remote tramming, auto leveling, auto drilling, and GPS navigation.

Standard equipment • Spacious thermal insulated cab with FOPS and noise abatement to less than 70 dB(A) • Excavator style chair and controls for increased comfort and visibility • Standard Cab pressurizer/ventilator/heater with the option to upgrade the pressurizer • Caterpillar 345SL undercarriage with hydraulic track tensioners • Hydraulic cylinders driven cable feed system • Hydraulic motor driven rotary head with spline lubrication, maximum 8,700 lbf-ft torque; speed range 0 – 150 rpm • Rotary Head tachometer integrated into the RCS system • Remote hydraulic tower pinning • Four-rod carousel for 6-¼" to 8-5⁄8" drill rods • “No Bump” rod changer • Hydraulically powered breakout wrench (fork chuck) • Hands-free auxiliary hydraulic chain wrench • 8,000 lb (3,629 kg) capacity auxiliary hoist • Hydraulically retractable dust curtains • Cooling package • Separate air intake filters for engine and air compressor • Wide flange structural steel beam frame with oscillation yoke mounting • 14-light night lighting package – 70 watt halogen • Full deck service catwalks and railings • Two 48" (1.2 m) and one 60" (1.52 m) stroke leveling jacks • 350 US gallon (1,325 L) fuel tank

Technical data Drilling Method

Rotary or DTH – Multi pass

Hole Diameter

6 3/4 in - 10 5/8 in

171 mm - 270 mm

Hydraulic Pulldown

70,000 lbf

311 kN

Weight on bit

75,000 lb

34,000 kg

Hydraulic Pullback

35,000 lbf

156 kN

Single pass depth

37 ft

11.3 m

Maximum hole depth

195 ft

59.4 m

Feed speed

127 ft/min

0.6 m/s

Rotary head, torque

8,700 Ibf•ft

11.8 kNm

Estimated weight

185,000 lb

84 tonnes

Length

54 ft

16.4 m

Height

67 ft

20.4 m

Width

23 ft 3 in

7.0 m

Dimensions tower up

Dimensions tower down Length

67 ft 7 in

20.6 m

Height

23 ft 3 in

7.0 m

Compressor range Low pressure rotary

1,900 [email protected] psi / 53.8 m3/[email protected] bar

Low pressure rotary

2,600 [email protected] psi / 73.6 m3/[email protected] bar

High pressure, DTH

1,450 [email protected] psi / 41.1 m3/[email protected] bar

Engine (Tier ll) Caterpillar

C27

800HP / 597 [email protected] (LP 1900)

Cummins

QSK19

755HP / 563 [email protected] (LP 1900)

Caterpillar

C32

950HP / 708 [email protected] (LP 2600)

Caterpillar

C27

800HP / 597 [email protected] (HP 1450)

Weg motor

6808

700HP / 521 [email protected] 50 or 60Hz

Weg motor

6811

900HP / 671 [email protected] 50 or 60Hz

Drill pipe specification: 40 ft (12.2 m) Drill pipe diameter

Suggested bit diameters

Thread

6 1/4"  (159 mm)

6 3/4" – 9"

4" BECO

7"  (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8"  (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8"  (203 mm)

9 7/8" – 11"

5 1/4" BECO

8 5/8"  (219 mm)

10 5/8"

6" BECO

High pressure DTH drilling Up to 8" DTH hammer and max. 9 7/8" bit diameter

Visit www.atlascopco.com/blastholedrills for more information

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DM-M3

Technical data

The Atlas Copco DM-M3 is a crawler-mounted, hydraulic tophead drive, multi-pass rotary drilling rig specifically designed for the blasthole drilling of 9-7⁄8 in. (251 mm) to 12-¼ in. (311 mm) diameter holes. The on-board depth capability is up to 240 feet (73 m) when using 8-5⁄8 in. diameter (219 mm) drill pipe and a 5-rod carousel. Standard drill pipe length is 40 feet (12.2 m). Hydraulic pulldown is featuring a patented hydrostatic, closedloop system acting through twin, double-rod hydraulic cylinders and cable.

Standard equipment

• Insulated, pressurized FOPS cab with heater • Rotary screw 2600 CFM @ 110 psi air compressor • Caterpillar C32 diesel engine (950 HP at 1800 rpm) • 13-light, 70 watt quartz-halogen night lighting system • Cab and ladder access lights plus dust curtain light • Cooling package • Remote hydraulic tower pinning • Auxiliary hoist of 8,000 lb (3,600 kg) capacity with lifting bail • Hydraulically-actuated, drill pipe carousel internal to tower for 4 drill pipe or 5 for 8- 5/8 in. diameter 40 ft. • Hydraulic sliding fork chuck breakout with auxiliary hydraulic wrench • 650 U.S. gallon (2,460 L) fuel capacity • Wide flange structural steel "I" beam main frame with oscillation yoke mounting • Separate three-stage air intake filters for engine and compressor • Rotary head tachometer • Three hydraulic leveling jacks and "jacks-up" indicator in cab • Hydraulically actuated rod support arm to align drill pipe during rod changing operations and when using the angle drill option • Full walkways and railings • 35.5 in (900 mm) wide, triple bar replaceble grouser pads • Rotary head with spline lubrication

Drilling Method

Rotary - Multi pass

Hole Diameter

9 7/8 in - 12 1/4 in

251 mm - 311 mm

Hydraulic Pulldown

90,000 lbf

400 kN

Weight on bit

90,000 lb

40,800 kg

Hydraulic Pullback

41,500 lbf

185 kN

Single pass depth

37 ft

11.3 m

Maximum hole depth*

200 - 240 ft

61 - 73.2 m

Feed speed

144 ft/min

0.7 m/s

Rotary head, torque

10,183 Ibf•ft

13.8 kNm

Estimated weight

230,000 lb

104 tonnes

Length

40 ft 5 in

12.3 m

Height

67 ft

20.4 m

Width

18 ft 11 in

5.8 m

Dimensions tower up

Dimensions tower down Length

66 ft 6 in

20.3 m

Height

23 ft 9 in

7.2 m

Compressor range Low pressure rotary

2600 [email protected] psi / 73.6 m³/[email protected] Bar

Engine (Tier ll) Caterpillar

C32

950HP / 709 [email protected] (LP 2600)

Cummins

QST30

950HP / 709 [email protected] (LP 2600)

Weg motor

6811

900HP / 671 [email protected] 50 or 60Hz (LP 2600)

Drill pipe specification: 40 ft (12.2 m) Drill pipe diameter

Suggested bit diameters

Thread

7 5/8"  (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8 5/8"  (219 mm)

10 5/8" - 11"

6" BECO

9 1/4"  (235 mm)

11" – 12 1/4"

6" BECO

10 3/4"  (273 mm)

12 1/4"

8" BECO

*Maximum hole depth only achieved with certain pipe sizes and wall thicknesses.

DM-M3

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper 311 The Pit Viper 311 is a crawler-mounted, hydraulic tophead drive, single-pass rotary drilling rig specifically designed for the blasthole drilling of 9 in. (229 mm) to 12 1/4 in (311 mm) diameter holes. It has a single-pass depth capability of 65’ (20 m) with total depth capability of 135’ (41 m). Its hydraulic driven cable feed system is capable of 110,000 lbf. (490 kN) of bit loading. Due to the light weight of the cable feed system the PV-311 can operate with a “live tower”. A patented automatic tensioning system eliminates down time for cable adjustments. It has several advanced options like an auto drilling system, auto levelling, remote tramming, and GPS navigation.

Standard equipment

• RCS rig control system, computerized network • New large insulated cabin with integrated A/C, large electrical cabinets housing computers, and a training seat. • 3000 CFM (84.9 m3/min) @ 110 psig (7.6 bar) air compressor • Atlas Copco 375 class under carriage with two speed hydraulic propel and automatic track tensioning. Optional: Caterpillar 350 Custom undercarriage with hydraulic propel and automatic hydraulic track tensioning • Optional: Fuel saving automatic hydraulic clutch • Dual Hydraulic cylinder driven cable feed system • Dual Hydraulic motor driven rotary head with spline lubrication • Two rod carousel for 7-5⁄8" to 10 ¾" diameter x 35' drill pipe • “No-bump” rod changer • Hydraulically powered breakout wrench (fork chuck) • Hands Free auxiliary hydraulic wrench • 8,000 lb (3,630 kg) capacity auxiliary hoist • Hydraulically retractable dust curtains • Four 72 inch (1.83 m) stroke leveling jacks • Cooling package • 700 U.S. gallon (2,649 liter) fuel tank; 1,400 gallon (5,300 liters) optional • Separate air intake filters for engine and air compressor • Wide flange structural steel I-beam frame with oscillation yoke mounting • Full deck service catwalks and railings • Automatic lubrication system • Nordic Night light package • Attention horn, propel alarm • Ground level shutdowns • Decking in tower (when horizontal) above rod changer • 35.5 in (900 mm) wide, triple bar replaceble grouser pads

Technical data Drilling Method

Rotary or DTH - single pass

Hole Diameter

9 in - 12 1/4 in

229 - 311 mm

Hydraulic Pulldown

100,000 lbf

445 kN

Weight on bit

110,000 lb

49,895 kg

Hydraulic Pullback

50,000 lbf

222 kN

Single pass depth

65 ft

19.8 m

Maximum hole depth*

135 ft

41.1 m

Rotary head, torque

13,800 Ibf•ft

17.5 kNm

Estimated weight

310,000 lb

140 tonnes

Length

48 ft

14.6 m

Height

100 ft 6 in

30.6 m

Width

25 ft 4 in

7.7 m

Dimensions tower up

Dimensions tower down Length

99 ft

30.2 m

Height

29 ft

8.8 m

Compressor range Low pressure rotary

3000 [email protected] psi / 84.9 m3/[email protected] bar 3800 CFM @110 psi / 107.6 m3/[email protected] bar

Engine (Tier ll) Caterpillar

C32

1125 HP / 839 [email protected]

Cummins

QSK 38

1260 HP / 940 kW @1800RPM

MTU

16V2000

1205 HP / 899 [email protected]

Engine (Tier IV) Caterpillar

C32

1125 HP / 839 kW

MTU

16V2000

1300 HP / 969 kW

Drill pipe specification: 35 ft (10.7 m) Drill pipe diameter

Suggested bit diameters

Thread

7 5/8"  (194 mm)

9" - 9 7/8"

5 1/4" BECO

8"  (203 mm)

9 7/8" - 10 5/8"

5 ¼" BECO

8 5/8"  (219 mm)

10 5/8" - 11"

6" BECO

9 1/4"  (235 mm)

11" - 12 1/4"

6" BECO

9 3/4" (248 mm)

12 1/4"

7" BECO

10 3/4"  (273 mm)

12 1/4"

8" BECO

*Maximum hole depth only achieved with certain pipe sizes and wall thicknesses.

Visit www.atlascopco.com/blastholedrills for more information

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Pit Viper PV-351 The Pit Viper 351 is a crawler-mounted, hydraulic tophead drive, single-pass rotary drilling rig specifically designed for the blasthole drilling of 10-5⁄8 " to 16 in diameter holes. It has a single-pass depth capability of 65’ (20 m) with total depth capability of 135’ (41 m). Its hydraulic driven cable feed system is capable of 125,000 lbf. (511 kN) of bit loading. Due to the light weight of the cable feed system the PV-351 can operate with a “live tower”. A patented automatic tensioning system is eliminating down time for cable adjustments. It has several advanced options like an auto drilling system, auto levelling, remote tramming, and GPS navigation.

Standard equipment

• • • • • • • • • • • • • • • • • • • • • • •

RCS rig control system, computerized network Insulated, air conditioned cab 3000 CFM (84.9 m3/min) @ 110 psig (7.6 bar) air compressor Caterpillar 385 Custom undercarriage with hydraulic propel and automatic hydraulic track tensioning Hydraulic cylinder driven cable feed system Hydraulic motor driven rotary head with spline lubrication Two rod carousel for 8-5/8" to 13-3/8" diameter x 35’ drill pipe “No-bump” rod changer Hydraulically powered breakout wrench (fork chuck) Hands Free auxiliary hydraulic wrench 12,000 lb (5440 kg) capacity auxiliary hoist Hydraulically retractable dust curtains Four 72 inch (1.83 m) stroke leveling jacks Cooling package 1200 U.S. gallon (4545 L) fuel tank Separate air intake filters for engine and air compressor Wide flange structural steel I-beam frame with oscillation yoke mounting Full deck service catwalks and railings Automatic lubrication system Nordic Night light package Attention horn, propel alarm Ground level shutdowns Decking in tower (when horizontal) above rod changer

Technical data Drilling Method

Rotary - Single pass

Hole Diameter

10 5/8 in - 16 in

270 mm - 406 mm

Hydraulic Pulldown

120,000 lbf

534 kN

Weight on bit

125,000 Ib

56,700 kg

Hydraulic Pullback

60,000 lbf

267 kN

Single pass depth

65 ft

19.8 m

Maximum hole depth

135 ft

41.1 m

Feed speed

127 - 158 ft/min

0.6 - 0.8 m/s

Rotary head, torque

19,000 Ibf•ft

25.7 kNm

Estimated weight

385,000 lb 415,000 lb

175 tonnes 188 tonnes

Length

53 ft 10 in

16.4 m

Height

103 ft 9 in

31.6 m

Width

26 ft 8 1/2 in

8.1 m

Dimensions tower up

Dimensions tower down Length

98 ft

29.9 m

Height

27 ft 11 in

8.5 m

Compressor range Low pressure rotary

3,000 [email protected] / 84.9m3/[email protected] bar

Low pressure rotary (electric motor)

3,200 [email protected] / 90.6m3/[email protected] bar

Low pressure rotary

3,800 [email protected] / 107.6m3/[email protected] bar

Engine (Tier l) 1650HP / 1230 [email protected] (LP 3800)

Caterpillar

3512

Cummins

QSK45

1500HP / 1119 [email protected] (LP 3000)

Weg motor

6811

1400HP / [email protected] 50 or 60 Hz (LP 3200)

Drill pipe specification: 35 ft (10.7 m) Drill pipe diameter

Suggested bit diameters

Thread

8 5/8"  (219 mm)

10 5/8" - 11"

6" BECO

9 1/4"  (235 mm)

11" – 12 1/4"

6" BECO

10 3/4"  (273 mm)

12 1/4" - 13"

8" BECO

12 3/4"  (324 mm)

15" – 16"

8" BECO

13 3/8"  (340 mm)

16"

10" BECO

Visit www.atlascopco.com/blastholedrills for more information

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RCS DRILL RIG OPTIONS

Rig Control System (RCS) The RCS creates an automated platform for the next generation of technologically advanced machines. Bulky equipment panels have been replaced by sleek, ruggedized, and easily accessible left and right operator panels with push buttons, joysticks and a touch panel screen. Through these panels, all rig functions can be controlled. By affixing these control devices to the chair, the operator will continually remain in full control of the machine no matter which way the operator turns to perform their duties. Providing the backbone for the system is the time proven yet remarkably agile Controller Area Network-bus (CANbus) standard. All sensors, control devices, and actuators are cabled into multiple strategically placed Input/Output (I/O) Modules.The I/O Modules, left and right operators panels, (optional) navigation system (GPS or GLONASS), and (optional) CCI module are connected into the back of the operators display which houses the central computer. All cabling is built off the latest CAN-bus Open standard utilizing molded cables.

RCS

RCS is the common platform shared throughout Atlas Copco´s equipment.

RCS is standard on: PV-235, PV-271 RCS, PV-275 RCS, PV-310 and PV-351

RCS Basic The RCS design provides many qualities that are advantageous to not only the operator, but also service technicians, mine planners, and mine management such as:

Flexibility

• Modularized system allows for easy add-ons, modifi- cations, and upgrades equating to minimal downtime • Onscreen calibration and adjustment of system parameters

RCS provides ease of operations even in toughest of environments.

A

B

C

Increased Productivity

• Computer display of all drilling pressures • On-screen display of powerhead position • Rock formation analysis and data logging • Learning curve dramatically decreased from drill-to-drill with standardized approach to controls and hardware • Auto-features provide optimal, consistent and predict able results

Ease of Maintenance

• Each I/O Module and sensor is equipped with LEDs to denote differing levels of performance. Quick deduction of variables aids decisive troubleshooting, ultimately decreasing MTTR • Adjustable automatic identification and display of system warnings and faults • Diagnostic menus and troubleshooting capabilities • Multiple interchangeable parts meaning less overhead and inventory • Display of engine J1939 data

(C) Sensors, control devices, and actuators are all cabled into five strategically placed (B) I/O Modules which are in turn connected into the (A) cab where the main computer is housed behind the operators screen.

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RCS DRILL RIG OPTIONS

Built-in

• Clean operating environment (The cab is sealed elimi nating hydraulic hoses, bulkhead connections, or leaks in the cabin) • Reduced noise • Automatic safety interlocks The RCS has controls, instrumentation buttons, and graphical user interfaces (GUI) that are common across other Atlas Copco RCS machines. The GUI provides multi-language support, built-in diagnostic system, controlled levels of access and menu based settings. The screen and joysticks are attached to the operator’s seat, so, as the seat swivels the joysticks and screen swivels in conjunction with the operator (they are always in an optimal and ergonomical location).

Leveling screen.

Add on Features Auto-Level System

The auto-leveling/de-levling option closes the gap between an average and expert operator, increasing the quality of setup. This feature reduces wear and tear on the machine structure by limiting torsional effect on the mainframe and tower during leveling. In normal conditions, this takes less than 35 seconds and is done to an accuracy of 0.2 degrees in pitch and roll.

From the settings screens, varying levels of access privileges allow for quick customized rig functions, creating a fine tuned comfortable drilling environment.

Auto-Drill System

When activated, this function will detect the rock when the bit touches the ground and start your air, dust suppression, rotation and feed to collar the hole. After the collared distance has been met, this control will adjust air, dust suppression, rotation and feed to a drilling setting. This feature will apply optimal pulldown and rotation to drill as fast as possible without stalling the rotation or getting stuck. Once the target depth has been reached, the auto-drill will clean or flush the hole, shutoff the air and dust suppression, and then return the bit to a tramming safe position. This feature provides the consistency of drilling to the correct hole depth, including water flow to maintain the hole so it does not collapse. Currently this is available for single pass drilling and multi-pass drilling, although a manual rod change must be made at this time.

Drill dashboard - drilling screen.

CCI – Common Communications Interface

The Common Communications Interface, or CCI, allows RCS to communicate to other entities and also allows data transfer to and from the RCS system. In order for the CCI to wirelessly communicate, the mine must provide the wireless communications device for their network. The optional CCI comes complete with the needed software and Ethernet cable.

GPS navigation screen.

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RCS DRILL RIG OPTIONS

RRA – Rig Remote Access System

The Rig Remote Access (RRA) software, which is loaded on a mine server, gives a customer the ability to wirelessly send files to and from the drill rigs in conjunction with the CCI and the mine’s wireless network. Utilizing a type of encoding, similar to a standard File Transfer Protocol (FTP) server, a number of working processes in the mine are simplified, saving valuable man hours. By having a direct link to the machines, work orders and log files can now be distributed on demand.

GPS – Global Positioning System

GPS hole navigation ensures each blast hole machine is precisely positioned per the mine engineers design. GPS antennas are mounted on the tower rest and radio antennas on the cab to produce an accurate bit position. Drill plans, designed with the local mine coordinates, are imported to the RCS in the International Rock Excavation Data Exchange Standard (IREDES) format, and the bit position is provided in real time. The bit position is calculated by taking into consideration the variability of the bench, providing the operator with correct depth to drill each hole. While tramming, the operator views a moving map display with zoom functions as the rig gets closer to the desired blast hole location. The dominant system for the precise positioning of a rotary drill on a blast hole drill plan is with satellite navigation based on GPS or GLONASS. Accuracies up to ±10 cm are possible to reach, depending on installation and the number of satellites. After each hole is drilled a new entry is created on the Quality Log file.

Surface Manager

Surface Manager is a software tool to view and create customized decision based metrics, graphs, and charts for a mine’s Pit Viper fleet. It utilizes the production logs created by RCS and is transmitted by USB or wirelessly through the RRA server. This reporting tool provides: • Drill usage • Consumable metrics • Planned vs Drilled Analysis (with AC HPGPS) • Rock hardness information

Utilizing the High Precision GPS option, drill operators can ensure near perfect and predictable hole positioning.

Each of the charts and graphs provide highly configurable options, allowing the user to view the precise information they require. Additionally, each chart and graph is exportable to both Excel and PDF, enabling the user to have a customized drill report. Centralized management of operator lists and delay codes is also contained in Surface Manager. For customers running the RCS GPS system, Surface Manager provides drill plan management. The system will take the mine’s CSV files and convert them into an IREDES drill plan for the Pit Viper. Surface Manager is flexible to either run in a centralized environment (SQL db with multiple client) or as a standalone client application. Surface Manager provides new tools to manage your drill fleet.

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RCS DRILL RIG OPTIONS

Production Logging The Production Logging option enables the drill to create and transmit three types of logs (Event, Status and Measure While Drilling (MWD)). These logs document a variety of drill parameters and events while the machine is running. Data is transferred from the RCS, either through the Common Communications Interface to the RRA server or by USB memory device connected during operations. The mine can use the gathered logs for a variety of reporting to build efficiencies and achieve greater results in operations the drills are a part of. Atlas Copco’s required format for data interaction is in the International Rock Excavation Data Exchange Standard (IREDES) format.

Production Logging Data Includes: • Date and time stamp • Depth tag • Penetration rate • Rotation Speed Torque • Air Pressure • Feed force • Hole information: ID, name, plan ID • Drill Information: Type, serial number, hours, state • Operator log-ins

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Quality Log File includes:

• GPS accuracy and quality (number of satellites available) • Average penetration rate • Total drill time • Hole number • Start hole position • End hole position • Drill rig info

Blasthole Drilling in Open Pit Mining

RCS DRILL RIG OPTIONS

Remote Propel System

The remote propel option allows the operator to wirelessly maneuver the drill using a handheld remote control within a 60-meter distance on the bench. This function will allow an operator to safely tram the rig; avoiding any potentially dangerous blind spots, prevent any damage next to a high wall or berm, or loading onto a lowboy. The remote control is equipped with safety triggers to ensure that the rig will not move unless the operator has full control to tram the machine. Featured on the device are an emergency stop button, engine speed control, dust curtain control, jack control, and cable reel control (electric units only). The system can be equipped with additional functions when available.

Teleremote

The teleremote operator panel has the same look, feel, and buttons as being onboard the drill. The package includes a four camera system with a one pan/tilt/zoom camera operated remotely and visible on a 32" screen. This compact system can be mounted on a table top or in a trailer. The teleremote system is to be operated over the mine network with capacity of 8 Mb/s dedicated per drill. The remote operator will have full confidence and awareness of what actions are taking place onboard the rig as well as in near proximity.

Remote propel handheld device.

Desktop Viewer

Through a simple software load on a mine networked computer, the drills current state can be accessed through our Desktop Viewer. The user will be able to view all of the RCS screens available to an operator as if they were in the cab using the touch panel. The drill will be required to be online via a CCI module.

The teleremote package is small in size, yet large in capability.

Technology...All in a days work Data Transfer

Production

Blast Decisions

Planning

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DRILL RIG OPTIONS

Electric power pack As an alternative to a diesel engine as the main source of power, several drill models can be configured with an electric power package, consisting of an electric WEG motor, starter and transformer. Electric versions are usually less costly to operate due to fewer lubricants, having an integrated cooling system, and no diesel fuel costs. In some cases, the operating cost advantage will in one year cover the additional investment cost for ordering an electric version. The service life of an electric motor is considerably longer than for an equivalent diesel engine, and has quieter operation. Weg motor options are available for: DML, DM-M3, PV-235, PV-271, PV-275, PV-310 and PV-351

Stainless steel battery & electrical boxes The Stainless Battery Boxes and/or Stainless Steel Electrical Boxes is now an available option. The Battery Box lid flips up, enabling the batteries to be easily pulled out on a roller tray. The Electrical Boxes all have a NEMA-4 Rating. Stainless Steel Battery Boxes available for: PV-271 RCS and PV-275 RCS Stainless Steel Electrical Boxes available for: PV-235, PV-271 RCS, PV-275 RCS, and PV-310

260-amp alternator This option is an upgrade from the standard option that comes on the machine to a larger alternator to suit each mine’s different requirements. Available for: PV-235, PV-271 RCS and PV-275 RCS and PV-310

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DRILL RIG OPTIONS

Ground level battery isolation & Jumpstart This option provides the mine with the ability to isolate all power on the machine with the turn of a switch. You can lock each switch in addition to the box to prevent anyone from accidentally returning power to the machine This option provides an easy access place to jump start dead batteries from ground level. The lockable stainless steel box has a see through door so that all persons can easily see the power status of the machine based on the LED lights. Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-310

Four jack configuration Stability in the set up of the drill rig is important for the drilling operations. All drill rigs are provided with hydraulic leveling jacks, as a basic “tripod arrangement” some models have an option of a four jack arrangement where the two non-drilling end jacks are tied together acting as one outrigger. Available for: DML, DM-M3, PV-271, PV-275 Standard equipment for PV-235, PV-310 and PV-351

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DRILL RIG OPTIONS

Cold weather operation • To secure trouble-free operation and a pleasant operator’s working environment, there are several cold weather options available including: additional cab heater, hydraulic oil and diesel engine heating, tank heaters, arctic hoses and cold weather fluids. • A well insulated and heated water injection system is available. • Gen-sets are available for some models of drill rigs. • Fully utilized these options allow the drill rigs to operate in arctic conditions.

Angle drilling package The Atlas Copco advanced angle drilling package allows the tower to be positioned from the vertical in increments of 5 degrees. All controls for positioning are located at the operators control console inside the cab. This system changes the pivot point on the tower to drill-deck level and ensures that the hole will always collar within the dust hood. This design also provides stability and ensures that a minimum length of the drill pipe will be unsupported between the centralizer and the collar. Good stability and guidance of the drill string during collaring and drilling will reduce hole deviation. High precision in drilling and blasting will improve fragmentation and contribute to lowering overall production costs Variations of the angle drill package are available on all other models Available for: All rigs

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DRILL RIG OPTIONS

Optional wrap around decking New decking options offer 360º complete access around the machine. The combination of the Cab Decking and the Extended Cooler Access Decking provide complete access to all components on the machine. The extended non-cab side decking adds approximately two feet of walking space, enabling you to access the back of the coolers. Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-310 Cooler Access Ladder: only available on PV-271 RCS and PV-275 RCS

Hammer sub holder This option will allow for the storage of two spare DTH hammer units on the rig for easy availability of spare parts on a mine site. They are located on the drill-end on the dust collector side. The extended non-cab side decking must be selected on the PV-270 RCS machines. Available for: PV-271 RCS, PV-275 RCS and PV-310

Tool holder An optional tool holder to securely carry brooms and shovels on the rig is available. Available for: PV-271 RCS, PV-275 RCS and PV-310

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DRILL RIG OPTIONS

Cranes An optional crane located on the drill end of the rig for loading bits is available. We offer either a HIAB or Auto Crane brand cranes. The Auto Crane comes with a remote control. Available for: PV-235, PV-271 RCS, PV-275 RCS

Lower rod catcher There is the option for an additional rod catcher located towards the bottom of the tower. Available for: PV-271, PV-271 RCS, PV-275, PV-275 RCS, PV-310 and PV-351

Hydraulic rod catcher An optional hydraulically operated lower rod catcher is available for the PV-270 RCS series. When closed, it will contain the drill rod within the tower and prevent it from falling out should one ever come loose. It can then be opened from inside the cab to allow the old drill rod to come out and a new drill rod to go in when it is time for drill rod replacement. Available for: PV-271 RCS and PV-275 RCS

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DRILL RIG OPTIONS

Auto-level system For the DM-M3, an AutoLevel system is offered as a way to achieve reliable and predictable leveling equating to speed and safety. This option has adapted the same proven hardware and software from our RCS equipped drills. Key points on the system: • Safety interlocks: Pitch and Roll limits • Auto-leveling/de-leveling times < 60 seconds • Auto-leveling pitch and roll within 0.2 degrees • View: 6.5” screen in cab for operator awareness, central computer and maintenance awareness • Control: Toggle switches integrate into existing panel for ease of turning feature on-and-off Available for: DM-M3

Under deck misting system Another option available is the misting system. This option provides the front of the machine, under the dust curtain, with a fine spray of mist to assists in suppressing dust created during tramming and drilling. Available for: PV-271 RCS, PV-275 RCS and PV-310

Delayed turbo shutdow timer This option can be installed to help protect the turbo in the engine. Typically when you turn off the machine there is still some oil in the turbo that does not have time to cool off. This option keeps the machine running for about five minutes after you turn off the key. This allows the turbo and engine sufficient time to cool off. Once the five minutes has passed, the machine fully shuts down. Note – when the Emergency Stop is activated this is by-passed and the machine shuts down immediately. Available for: PV-271 RCS, PV-275 RCS and PV-310

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DRILL RIG OPTIONS

Water injection system The water injection system injects a regulated quantity of water into the air flow going to the drill pipe. The water content in the air-flushing suppresses the dust created by the drilling operation. The water injection system has a hydraulic motor drive, and is operated from the cab control system. There are several sizes of water injection systems available, and the injection tanks are either mounted within the frame or on the deck to ensure the drilling water requirements are met.

Dust collector Different sized “no visible emission” dry dust collectors are available. The design features a pleated paper element type fan/filter unit. Interval flushing is controlled by an electronic timer. A vacuum hose allows the fan/ filter unit to draw the dust out of the collection area. The dust is removed from the air stream as the air flows through the pleated paper filter elements. Heavy cuttings are contained around the hole. Operation of the dust collector is controlled from the cab control system.

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DRILL RIG OPTIONS

Hydraulic ladder This Atlas Copco option allows the operator or maintenance personnel an easy approach onto the machine. Instead of having to hoist themselves up a vertical ladder, this enables hands to be free for other needs, such as carrying tools. There are integrated safety interlocks* built into the ladder that will prevent the drill from moving if the stairs are deployed, as well as isolation and lockout features. *Tramming Isolation on RCS Machines only Available for: PV-235, PV-271 RCS, PV-275 RCS, PV-310 and PV-351

Tower support infill option The newly designed tower infill is to provide mine personnel with a dedicated and secure spot to stand when access to the gear box, the valve bank, and under the tower support is required. The infill is made of sturdy slip-resistant decking and also helps with hose management. Available for: PV-271 RCS and PV-275 RCS

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DRILL RIG OPTIONS

Oil centrifuge system option This option siphons off about 10% of the engine oil delivered by the engine oil pump before it reaches the normal engine oil filter. The oil then is returned to the sump. There is no physical “FILTER” to change or clean; maintenance has to remove the lid and the rotor, and scrape out the dirt that has formed. The results vary depending on environment and ensuring that regular samples are taken. Available for: Depends on engine configurations

Engraved hydraulic schematic This option provides the machine with an engraved schematic of the hydraulic system that is then adhered to the hydraulic tank for easy reference during maintenance and troubleshooting on the machine Available for: PV-271 RCS, PV-275 RCS, PV-310 and PV-351

Live sampling The Live Sampling System has the ability to take samples for hydraulic oil, engine oil, and compressor oil. This system continually circulates through this area so samples are “fresh” and not stagnant. Note: Have to select Fast Service Box in order to get this option Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-310

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DRILL RIG OPTIONS

Tower restraint system The tower restraint system is a dedicated resource providing a safe means of conducting maintenance in our towers. A specially designed staircase consists of individuals steps that are made of sturdy steel grating. The Stairway also consists of two signed gates at both the bottom and the top, handrails, and a spacious work platform. The Tower Fall Restraint system incorporates a set of cables and harnesses. Once inside the tower you have access to the cables that are permanently anchored to the tower cords and include a shuttle on each side on which to hook the harness. These shuttles are an integral part of the structure and include a double-locking mechanism for safety purposes and are specially designed to withstand the vigors of a mining environment. They allow the operator full access to the tower, as well as being able to smoothly move over transition pieces without the hazardous practice of having to unhook from the cable, allowing the individual to keep their hands free for tools and the task at hand. Available for: PV-235, PV-271, PV-275, PV-310 and PV-351

Additional NDE water tank An additional 1600 l (422 gal) NDE water tank is now available for the PV-271 and PV-275 machines. This water tank mounts onto the newly redesigned tower rest on the non-drill end of the machine. Note: Diesel Machines Only Available for: PV-271 RCS and PV-275 RCS

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DRILL RIG OPTIONS

Mesabi coolers Mesabi coolers are special cooling fans specifically designed to handle the cold weather environments. These arctic coolers are available either from the factory or as a field retro-fit. They can operate in temperatures as low as -40°F (-40°C) upwards to 125°F (52°C). Available for: DM30, DM45, DML, PV-235, PV-271, PV-275, and PV-310

Mesabi cooler.

Ground level shut down All rigs are provided with a standard emergency shutdown button mounted in the cab. As an option, one or several additional ground level shutdown buttons can be provided for mounting all over the machine. By pressing the ground level shutdown button, the power to the engine is then disconnected.

Emergency ladders In order to better prepare for the event of an emergency, now offered are either one or two emergency ladders on the non-drill end of the machine. These ladders flip out with a quick release and provide a swift means of escape in the event that they are needed. When they’re not in use, the ladders fold up onto the rig and re-latch. Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-310

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DRILL RIG OPTIONS

Engine roof The Engine Roof fits over any engine configuration. It helps protect the machine from a possible fire by providing a physical barrier between a leaky hose and a possible ignition source. Available for: PV-235, PV-310, PV-271 RCS and PV-275 RCS

Extended non-cabside decking and bit basket Two integral parts of our 360º deck access are the drill-end extended decking with a bit basket and the extended cooler decking. The drill-end decking extension is an option that includes a built-in bit basket on the drill-end of the machine. By adding this decking option, you not only gain complete access to the machine, but also have a safe, secure, and dedicated spot to store bits. This option inhibits bits from being laid unsecured on the deck, opening up a possibility for them to shift and move during tramming. By choosing the additional extended cooler decking, you add approximately 2 feet (61 cm) to the non-cab side of the machine. This allows uncon-strained access to the back of the coolers for cleaning, maintenance, or a walkway to other areas of the machine. Available for: PV-235, PV-271 RCS and PV-275 RCS

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DRILL RIG OPTIONS

Auto-thread lubrication system The system includes a cab-activated button that initiates flow of grease through either pneumatic or electric pump to a nozzle. The nozzle is located on the drill table, and sprays the grease at the pipe joint threads. This helps to extend the life of your pipe threads when changing rods. Pneumatic only available for: T4BH, DM25 and DM30 Electric only available for: DM45/50, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV-275 RCS, PV-310 and PV-351

Central lubrication system The Quicklube lubrication system is designed to provide a relatively simple and inexpensive method of centralizing and automating the lubrication of machinery bearings. The system dispenses small measured amounts of lubricant at frequent intervals while the machine is operating. With a fully automated system, the lubricant is supplied by an electric pump through one or more distribution blocks to each point covered by the system. Even those hard to reach areas are assured of being properly lubricated and purged of contaminants. Up to 300 lubrication points can be served, depending on the length of the hose. • Reliably distributed lubricant in pre-determined amounts. • Delivers lubricant to the connected lubricant points in a safe manner. • Each lubrication circuit is equipped with a safety valve that holds the pressure within permissible values. • If there is a block in a lubrication circuit, lubricant will leak from the safety valve. • Works through lubrication cycles (interval time, propagation time and load time). Can be used in cold weather applications if special low temperature grease is used. Option for: T4BH, DM25SP, DM30, DM45/50, DML and PV-235 Standard equipment for: PV-271, PV-271 RCS, PV-275, PV-275 RCS, PV-310 and PV-351

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DRILL RIG OPTIONS

Remote tramming system The optional remote tramming system offers the operator the ability to move the rig from a drive pendant, which can be worn on the operator’s shoulders. The remote tram pendant is connected to the rig by a cord, and is operated by similar joysticks as those used on the operator’s panel in the cab. Available for: DM45, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV-275 RCS, DM-M3, PV-310 and PV-351 Note: On RCS rigs this option is wireless, see page 215

Remote control unit with cord connections.

Central hydraulic test station The central hydraulic test station allows for testing of component pressures. A standard test fitting gauge can be used and plugged into the desired port for reading of the system pressure. The hydraulic test station is mounted on the deck for easy accessibility. Available for: T4BH, DM45, DML, PV-235, DM-M3 Standard equipment for PV-271, PV-275 and PV-310 (not required for RCS rigs - electronic sensors are included in the RCS system)

Fire suppression system A dry-chemical fire suppression system can be provided with manual activation points. The system is provided with canister(s) that are located on the deck of the machine. The fire suppression canister contain a dry chemical fire suppressant which utilizes a nitrogen cartridge for the pneumatic actuator. Several discharge nozzles located throughout the machine will spray the suppressant when the system is activated. This fire extinguisher agents is rated for extinguishing type A (trash/wood), type B (liquids) and type C (electrical equipment) fires. The fire suppression canister can be recharged as needed.

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DRILL RIG OPTIONS

Drain System The Drain System is a centrally located box on ground level where the mine can attach a drain hose to any port and quickly evacuate any and all fluids on the machine. Available for: PV-235, PV-271 RCS and PV-275 RCS Standard equipment for: PV-310

Fast Service System Fast Service system with ground level, quick connect fittings for quick fill of fuel, hydraulic oil, engine oil, engine coolant, water (if water injection installed), and bit lube (if bit lube is installed) is an available option. Each different fluid port comes with a different sized connection point to avoid accidental cross contamination of liquids, as well as a matching set for the mine to use on their refilling hoses. There is also an additional upgrade to option to the HydrauFlo system which is a safer, cleaner and more reliable fuel filling valve arrangement which removes the risk of overfilling, spillage and tank rupture while minimizing safety and environmental hazards associated with fuel and water transfer. Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-351 Standard equipment for: PV-310

Racor fuel filter The Racor fuel filter is specifically designed to separate any water that may be in the fuel lines, and a Racor fuel filter with the heater option, as shown, is available for some models and engine configurations.

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DRILL RIG OPTIONS

Stereo with CD player The operator’s cab can be equipped with a stereo system with AM/FM radio, CD player, mp3 jack and speakers. The package also includes a battery equalizer for 24V to 12V DC conversion. Available for: DM45, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV-275 RCS, DM-M3, PV-310 and PV-351

Engine pre-lube system Special engine pre-lube assembly systems are available both for Cummins and CAT diesel engines. The engine pre-lube, lubricates the valve zone prior to engine startup, giving the benefit of less wear and tear on the engine over time Available for: DM45, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV275 RCS, PV-310, DM-M3 and PV-351 Standard equipment for PV-351 (Cummins)

Towing package Tow hooks or a tow bar mounted on the non-drill end of the rig allow for towing. Available for: DM45, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV-275 RCS, DM-M3, PV-310 and PV-351

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DRILL RIG OPTIONS

High intensity discharge lights The high intensity discharge (HID) night light package consists of upgrading the standard halogen lights to Xenon 24V, 35 Watt lamps. With this upgrade the HID lamps will be mounted in the standard lamp locations. The HID lamps have great luminous intensity and a color mimicking natural daylight. These lamps are designed specifically for forestry, mining and earth moving applications, and are designed to have low power consumption. Lights can be turned on when the engine is on or off. Available for: DM30, DM45, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV-275 RCS and PV-310

Sodium 240 Volt night light package The 240 VAC night light package consists of additional 400 Watt high pressure sodium lights and additional 150 Watt high pressure sodium lights. These lights are installed in addition to the standard light package on the rig and require power from an external 240 VAC power source (like an optional gen-set). Available for: DM45, DML, PV-271, PV-275 and DM-M3 Standard equipment for PV-351 Electric

LED Lights The LED night light package consists of upgrading from the standard halogen lights to LED lights (quantities vary per machine). With this upgrade the LED lights will be mounted in standard lamp locations plus a few additional locations. The LED lights have great luminous intensity, enough bright color to light up any bench. LED lights tend to typically consume less power. Lights can be turned on when the engine is on or off. Available for: PV-235, PV-271 RCS, PV-275 RCS, PV-310

Tower light marker There is also an option to place two amber lights on either side of the top of the tower. The purpose for these lights are to notify surround machine operators of where the tower is when it is in the down position. Available for: PV-271 RCS, PV-275 RCS and PV-310

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Buddy seat If an additional seat is required in the cab, a fold-up buddy seat can be mounted inside the cabin. Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-310 (in addition to the standard bench) Available for: DM45, DML, PV-271 and PV-275 (different version than pictured)

Torque limit control Rotational torque limit control is standard on high pressure drill rigs, and is an option available for low pressure rigs. The torque limit gauge and controller are mounted in the cab and operate an electrically controlled remote valve. Torque limit control is used to limit the rotation pressure within the closed loop rotation circuit. Available for: DM25, DM30, DM45, DML, PV-235, PV-271 and PV-275

Cab sunshades Pull down, sunshades located on all windows are available. Available for: DM30, DM45, DML, PV-235, PV-271, PV-275, DM-M3, PV-310 and PV-351

Drill window guard An optional guard over the cab window closest to the drill tower is available. The guard will protect against any objects that could potentially fall from the tower. The guard will protect the window and absorb the impact of the fall. Available for: PV-235, PV-271 RCS, PV-275 RCS and PV-310

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DRILL RIG OPTIONS

EARS The optional Electronic Air Regulation System (EARS) is designed to deliver variable air volume control, while still maintaining constant air pressure. This allows for savings in power and fuel consumption. Available for: DM45, DM50 and DML Standard equipment for: T4BH, PV-271,PV-271 RCS, PV-275, PV-275 RCS, PV-310 and PV-351

Video camera system For improved safety and visibility around the drill rig, an optional video camera system can be installed. The system consists of three or four rig mounted video cameras and a LCD display screen mounted inside the cab. Each camera has a motorized lens cover for protection, and contains a heater which automatically turns on when the temperature falls below 50° F (10°C). The cameras are installed in water resistant housings, complete with illuminators for low light conditions. The camera image device is an interline – transfer 0 type CDC, with a picture resolution of 270,000 pixels (horizontal resolution of 380 TV lines and a vertical resolution of 350 TV lines). The monitor is a 6.8” LCD screen with an auto dimmer. Screen resolution is 270.000 pixels, and screen controls include: bright, contrast, color, tint, image selectable, auto scan time and scale (on/off) Available for: DM30, DM45/50, DML, PV-235, PV-271, PV-271 RCS, PV-275, PV-275 RCS, PV-310, PV-351 and DM-M3

Microphone mute There is the option available on the PV-271 to have a mic-mute system installed with the stereo. This system will mute the stereo when the radio mic is cued. Available for: PV-235, PV-271 RCS, PV-275 RCS, PV-310 and PV-351

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DRILL RIG OPTIONS

Secondary air conditioning unit The option to have a secondary air conditioning unit is available. This unit mounts at two positions on the outside of the cabin and is electrically run-off of 24VDC. It also consists of three additional vents inside the cab. Available for: PV-235, PV-271 RCS and PV-275 RCS

Cab map lights Another option available is for the addition of three map-reading lights located in the cab. One is located on the dash by the door going to the powerpack, one is mounted on the chair, and the third is mounted in the corner of the windows above the buddy seats. Available for: PV-235, PV-271 RCS, and PV-275 RCS

Optional bit-viewing hatch Another option available is a bit-viewing hatch installed in the decking just outside the cab, which will allow the operator the ability to view the cuttings coming under the dust flaps. The hatch can be controlled from inside the cab. Available for: PV-271 RCS and PV-275 RCS Floor window available for: PV-235

Optional XIR glass XIR Glass is a laminated glass that is stronger than the standard laminated glass. It uses an infrared heat layer to reflect heat away. The XIR Glass is also approximately 50% thicker, due to the middle plastic safety layer being twice as thick than the standard glass, making it significantly stronger. Available for: PV-235, PV-271 RCS, PV-275 RCS, PV-310 and PV-351

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Air compressors and Boosters

Hurricane B4-41/900 booster A stand-out that meets T4 emission standards Atlas Copco Hurricane has embraced the challenge of the new EPA Non-road Regulation Tier 4 emission standards to create the B4-41/900 booster model with a Cummins QSB4.5 Tier 4i diesel engine. Based on the B7-41/1000 booster’s proven design concept, the B4-41/900 provides additional flexibility in drilling applications, with models available for exploration, mining, oil and gas and construction—wherever there is a need for a 900 psi single-stage booster in a more compact package. The B4-41/900 features a flat base frame and single-point lifting, with optional bolt-on protection frame. Oversized forklift pockets and small overall footprint increases maneuverability. A pre-cooler bypass system supports cold weather operation.

Standard Features • Automatic load/unload system • Double-acting concentric valves • Watercooled booster and diesel engine • Precooler (a+15°F / 8°C) & suction scrubber tank • Aftercooler (a+50°F / 28°C) • Open skid with single point lifting and fork lift slots • Low-pressure switch at booster inlet • Suction, interstage and discharge safety relief valves • Full-function instrument panel monitoring all pres sures, temperatures and controls with full-protection shutdown and fault indicators Other B4-41 options, pressures, and capacities are available upon request.

Specifications

236

Booster type

Model 276 – 4 cylinders, reciprocating

Booster stages

1 stage operation

Max suction pressure

350 psi / 24 bar

Overall dimensions, L x W x H

98 x 70 x 68 inches / 249 x 178 x 172 cm

Blasthole Drilling in Open Pit Mining

Air compressors and Boosters

M-41/1000 Booster Module Large power in a small footprint Built with the same values as the new B7-41 and B4-41 models, the Atlas Copco Hurricane M-41 has a capacity of 2,440 scfm (69 m3/min.) at maximum 1,000 psi (69 bar) discharge, but its small footprint is compatible with installation on water well and reverse circulation drill rigs, as well as on mobile drill platforms. Its compact size and light weight give customers, even in high pressure markets, increased flexibility in their applications. The M-41 features fork lift pockets in the base frame, a remote mount control panel, and a digital temperature scanner. The M-41 offers several options for the unit’s prime mover, including hydraulic or electric motor, PTO/belt drive, or diesel engine.

Standard Features • Automatic load/unload system • Double-acting concentric valves • Watercooled booster block • Precooler (a+15°F / 8°C) & suction scrubber tank • Aftercooler (a+50°F / 28°C) • Open skid with fork lift slots • Low pressure switch at booster inlet • Remote mounted instrument panel monitoring all pressures, temperatures and controls with full protection shutdown and fault indicators Other options, pressures, and capacities are available upon request.

Specifications Booster type

Model 276 – 4 cylinders, reciprocating

Booster stages

1 stage operation

Max suction pressure

350 psi / 24 bar

Overall dimensions, L x W x H

54 x 57 x 65 inches / 137 x 145 x 165 cm

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Air compressors and Boosters

Atlas Copco Some nice picture of XRVS 476 /1000

Quantum leap hamPortable Diesel Oil-flooded Compressor mers to put here With normal operating pressure 25 bar (363 psi), this Atlas Copco rotary screw compressor is designed for continuous duty in harsh conditions. The ability to vary pressure outputs from lower to higher makes it ideal for a wide variety of applications a wide variety of applications where auxiliary air is needed. Leak-free chassis and central fluid drain system protect the environment. Easy access to all service points reduces maintenance time and operating costs. And Zincor-treated canopies with powder coat paint finish mean improved resistance to corrosion for long life and high resell value. Standard Features • Quiet operation —72 decibels at 7 meters • Tier-III/Stage-III compliant Caterpillar 6 cylinder, 317 kW (426 hp) engines • Fuel consumption 75 l/h at full load. • Guaranteed free air delivery of 975 cfm (460 l/s) • Maximum operating pressure 392 psi (27 bar) • Minimum starting temperature 14° F (-10° C) • Maximum ambient temperature 113° F (45° C)

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drill string

Secoroc rotary drill strings A complete rotary drilling system In rotary drilling, the selection of each purpose suited drill string component is vital to achieve accurate holes and operational efficiency – parameters which affect operational costs. When developing a rotary drilling system, most of the attention is given to the drill rig – the capital equipment that requires significant investment and hence a planned payback. The second priority in the system tends to be choice of rotary tricone drill bit. However, to utilize the full power and capacity of the rig and the bit and at the same time increase service life and productivity, serious consideration should also be given to each component within the drill string. The optimal drill string includes a shock absorber at the top, a rotary deck bushing to centralize the drill string as it passes through the deck of the drill rig, strong and straight drill pipes and finally a hole stabilizing roller stabilizer or bit sub-adaptor to optimize the performance. Giving the necessary attention to every part of the drill string will lead to the lowest total drill operating costs. The primary purpose of the drill string is to transmit the rotational torque and weight from the rotary head power source to the rock breaking drill bit. As in every rock drilling method, the power must be transmitted as efficiently as possible, and return as few vibrations as possible, as these cause unnecessary wear on the drill rig and reduces penetration rates.

When selecting components for the drill string, attention must be given to the different roles of the support tools in the string. With the Secoroc rotary drill string the aim is to always: • Absorb damaging vibrations from the bit. • Reduce wear on the drill rig’s rotary drive, mast and power train. • Improve transmission energy from the rotary head to the drill bit. • Centralize drill string within the hole, ensuring axial alignment top to bottom. • Longer and more effective bit life. • Compliment performance potential of the drill rig and drill bit. • Reduce friction as the drill string passes through the drill rig deck. • Increase penetration rates, lowering total drilling costs. • Achieve blasthole accuracy for improved blasting efficiency. • Improve the end result – the correct fragmentation of the blasted rock for lower downstream operating costs! Visit www.atlascopco.com/secoroc and www.atlascopco.com/blastholedrills for more information

Secoroc drill strings for the Pit Viper series Diameter

PV-235

PV-271

PV-275

PV-311

PV-351

4 ½" (114 mm)



5" (127 mm)



5 ½" (140 mm)



6-¼" (159 mm)







7" (178 mm)









7 5/8" (194 mm)









8" (203 mm)





















8 5/8" (219 mm) 9 ¼" (235 mm) 9 ¾" (248 mm)



10 ¾" (273 mm)



12 ¾" (324 mm)



13 /8" (340 mm)



3

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Rotary drilling TOOLS

Tricone rotary blasthole drilling

Introduction

Tricone drilling can move much more material in a given amount of time than DTH drilling due to the generally larger diameters used, but Tricone drilling may be a less “ore grade sensitive” method due to larger bit diameters and therefore greater hole burden and spacings used. Ultimately, the mine’s “production cost” is the economic driver: at the end of the day, which method gives the lowest COST PER TON of material blasted?

An impressive legacy

Atlas Copco Secoroc LLC traces its beginnings back to Howard Hughes, Sr., inventor of the first two-cone rotary drill bit for rock in 1909. “Our purpose is to never be satisfied but will continue, with the help of our experienced engineers, to anticipate the requirements of the drilling industry.” The words spoken by Mr. Hughes are valid at Atlas Copco Secoroc LLC today. Howard Hughes, Sr. left behind an impressive inventor’s legacy, having held 73 distinct patents. The company continued to be a leader in development, with the introduction of the first TriconeTM rock bit with inter-fitting teeth in 1933, and the first Tungsten Carbide Insert rockbits in 1951.

Lowering our Customers Total Drilling Cost (TDC)

Atlas Copco Secoroc LLC is dedicated to reducing the customer’s total drilling costs while maintaining the highest standards of quality. Atlas Copco Secoroc LLC has repeatedly shown customers that a better bit, though more expensive, actually reduces the cost of the drilled hole. When a mining engineer or a purchasing group takes into account the total cost of operating a drill, it is easy to see that the best way to cut costs is to drill the hole faster. Our goal is not to just meet your expectations, but to exceed them. As part of our commitment to continuous improvement, we constantly look for ways to make our products drill faster and more efficiently.

Tricones or DTH?

How do you decide on which drilling method to use, Rotary Tricone drilling, or Down The Hole hammer drilling? Each has several factors in its favor. DTH drilling in hard ground generally has higher penetration rates than Tricone drilling, and exerts less wear and tear on the drill because heavy “pulldown” forces are not used with DTH. But it is much more labor, consumables, and inventory intensive than tricone drilling. In soft ground, DTH drilling tends to be problematic. DTH loses its penetration rate advantage at 9 to 10 inch diameter (229 - 254 mm) in “hard” rock.

240

Let’s consider this example, for a straight forward “rock removal” scenario: • 12 1/4” Tricone bit and suitable drill • 100 feet (30.5 m) per hour penetration rate • 50 foot (15.2 m) bench height, plus subdrill • US$300/hour drill operating cost • 9” DTH and suitable drill • 50 foot (15.2 m) bench height, plus subdrill • 125 feet (38.1 m) per hour penetration rate • US$200/hour drill operating cost

Which method has the lowest cost per ton?

Using the Hustrulid blasting calculations presented in the various Atlas Copco Academy sessions (which calculate burden, spacing, subdrill, and stemming based on hole size, face height, and rock and explosive SG), we see the following production costs: 12 ¼" Tricone & Big drill

9" DTH & Small drill

$300

CPH

$200

100

ROP

125

5676.9

Tons per hour produced

3970.2

1

Drill required for tonnage

1.430

$0.053

Op cost/ton/drill

$0.050

$0.053

Actual cost/drilled ton

$0.072

In this example, DTH drilling is almost 50% more costly than using Tricones. In fact, it takes another 17% increase in Rate of Penetration, to 146 feet/hour, for the DTH method to equal the Cost per Drilled Ton of the Tricone method. Depending on the commodity mined, the geometry of the mining benches, the tonnage production rate needed, etc., it is advised that rotary Tricone drilling always be investigated as a more cost effective way to correctly serve the customer.

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Tricone rotary blasthole drilling

Elements of a rock bit

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Rotary drilling TOOLS

Tricone rotary blasthole drilling

Bit elements

Cones

Carbide Insert Rows

Cones make up the cutting elements of the rock bit and are comprised of the following:

A. Nose B. Inner C. Next to Gage D. Gage E. Gage Bevel

1. Tungsten Carbide Inserts - which are pressed into the softer steel material with interference fit to hold item in place. 2. Cone Thrust Button - Made of a wear resistant material used to take axial bearing loads. 3. Outer Cone Shell - Insert land’s and cone grooves. 4. Cone Bore - Internal ball and roller bearing races.

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Rotary drilling TOOLS

Tricone rotary blasthole drilling

Bit elements

Lugs Coupled in threes, by 120º to form the bit body and the pin connection, the lugs are machined to hold the nozzles and a journal-bearing surface.

Nozzles Nozzles are used to create back-pressure in the bit to force air through the bearing airways and increase the “air-blast” force to remove and flush cuttings from the bottom of the hole. Too large of a nozzle will cause insufficient volumes of air to be delivered to the bearings, while too small of a nozzle will increase the back-pressure above the compressor modulation setting. When the compressor’s modulation setting is reached, it will then reduce it’s volume output causing a decrease in (air?) volume going to the bit.

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Rotary drilling TOOLS

Tricone rotary blasthole drilling

Tricone bit inserts

Inserts are the actual physical elements that spall and break the rock. Inserts are made from tungsten carbide powder and a cobalt binder material, which is pressed into the designed shape then sintered. Depending on the application, the tungsten carbide inserts in a given bit will have a shape and physical properties best suited for the rock being drilled.

Conical

90º Chisel or trimmer

Chisel

Wedge crested chisel

Ogive

Serrated flat top

Super Scoop

Double Angle Conical

The conical insert is used primarily in medium/medium-hard rock. It is designated in the bit nomenclature with a C.

The chisel insert is used in soft/ medium-soft rock. It is the standard insert in soft bits (40’s & 50’s) and is designated with an F in the bit nomenclature.

The ogive insert is used in areas where the aggressiveness of the conical insert is required with additional toughess. The ogive is designated as an O in the bit nomenclature.

The super scoop is used in very soft rock. With the patented offset tip, digging and gouging help penetrate in sticky materials. The super scoop is designated with an S in the bit nomenclature.

The trimmer is used specifically in the MAGNT product line. It enhances the gage rows ability to cut the bore hole wall. The MAGNT feature is used in soft to medium brittle rock formations.

Wedge crested chisel inserts are used exclusively on the gage rows of very soft to hard bits (40’s through 60’s). This shape gives a fracture resistant insert that is much tougher than concial or regular chisel inserts on gage. Serrated flat top inserts are used on shirttail lips and along the lug as “armor” to protect against shirttail and lug wear.

Double angle concial inserts with hardmetal retard erosion and provides for increased ROP.

Round top

The ovoid or round top insert is used in the hardest formations. Its blunt geometry gives it the most fracture resistant design. The round top is the standard insert in hard bits (60’s 70’s & 80’s) and is designated with an N in the bit nomenclature.

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Rotary drilling TOOLS

Tricone rotary blasthole drilling Atlas Copco Secoroc LLC uses the IADC (International Association of Drilling Contractors) code along with the product line and added bit features to help describe the bit. The IADC code is a three numbered system to classify the hardness and type for all roller cone rock bits.

First digit – Identifies the bit type and major hardness class: 1 – Steel Tooth for soft formations 2 – Steel Tooth for medium formations 3 – Steel Tooth for hard formations 4 – Insert for soft formations 5 – Insert for soft/medium, formations 6 – Insert for medium/hard formations 7 – Insert for hard formations 8 – Insert for extremely hard formations Second digit – Designates the hardness subclass of major hardness class. This ranges from 1 to 4, where 1 is classified as the softest subclass and 4 is the hardest subclass.

Third digit – Designates the bit’s features: 1 – Roller bearing 2 – Roller bearing air-cooled

Product lines:

• eM – epsilon technology evolved from the MAG product line. Wide variety of drilling applications using streamlined lugs for greater bailing area and allowing rapid evacuation of cuttings. Balanced cut ting structures for improved bearing loading, lowered carbide stress and higher capacity bearings for longer life. •

eH – epsilon technology evolved from the HD product line. Wide variety of drilling applications using streamlined lugs for greater bailing area and allowing rapid evacuation of cuttings. Balanced cutting struc tures for improved bearing loading, lowered carbide stress and higher capacity bearings for longer life.

• Om - Omega Sealed Bearing Products Current sizes are 9 7/8" (251 mm), 10 5/8" (270 mm), 12 ¼" (311 mm) and 13 ¾" (345 mm). Selected bit types in each size from IADC class 4-2 bits up to IADC class 6-4. Sealed ‘journal bearing’ or sealed ‘roller bearing’, depending on bit diameter. Bit cones designed for erosion resistance with high insert retention aspects, to prevent loss of inserts in erosive/abrasive conditions. Streamlined epsilon style lug to maximize cuttings removal from bit and hole bottom. Proprietary carbide grades to maxi- mize both insert “toughness” and resistance to abrasion.

3 – Roller bearing with gage bevel inserts

Insert/Tooth Type:

4 – Sealed roller bearing

• • • • • •

5 – Sealed roller bearing with gage bevel inserts 6 – Sealed friction bearing 7 – Sealed friction bearing with gage bevel inserts 8 – Directional 9 – Other

Nomenclature

C – Conical D – Double Angle Conical N – Round Top O – Ogive S – Super Scoop F – Chisel

In Steel Tooth (or Mill) Bits: 1 to 5

Example:

IADC 6-3-2 This is a medium/hard air-cooled roller bearing.

Example:

12 ¼ eH63CA 12 ¼ – Size eH - Product Line: e = epsilon; H = harder drilling – Product Line 63 – First two digits of the IADC code (rock class "6" subclass "3") C – Insert type (Conical inserts) A – Full armored lug

• • • • •

1 – Conventional Gage Tooth 2 – Tapered Gage Tooth 3 – “T” Gage Tooth 4 – “L” Gage Tooth 5 – “Web” Gage Tooth

Ovoids are standard inserts and do not have suffixes.

Lug Features: • • • •

A – Armor B – Backreaming ST – Shirttail protection in tooth bits R – Regular circulation

Other Features: • • • •

H – Hard Nose on cones G – Gage bevel on tooth bits T – Tough carbide (breakage resistant) W – Wear resistant carbide

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Rotary drilling TOOLS

Steel tooth bit selection Soft formation bits The Type S, regular circulation steel tooth bit is designed for optimum performance in formations of low compressive strength, such as soft sand rock, calcite, shale and clay. These formations quite often contain abrasive materials such as sharp sand and may be interspersed with layers of medium and hard formations. Soft formation bits are designed with long slim, strong teeth to permit deep penetration into the formation with comparatively light weight. Also, bit geometry is adjusted to give maximum desirable scraping action on bottom. So specific range of footage or penetration rates can be used as a yardstick for determining when to stop using this type bit, due to wide variation in weight, rotary speeds and formation variations encountered. However, if excessive tooth breakage occurs, you might safely assume that either the combination of weight and rotary speed is too great or formation is too hard for this type bit. Normally, these bits are run with relatively light weights, ranging from 1,000 pounds to 3,000 pounds per inch of bit diameter. Rotary speeds usually range from 120 to 170 revolutions per minute, depending upon the weight applied to the bit.

Medium formation bits The Type M and regular circulation steel tooth rack bits are designed for abrasive and non-abrasive medium formations. Note that this design differs from the “softer” types principally in the progressive strengthening of the teeth and change in bit geometry to provide more chipping-crushing action. These bits have more closely spaced teeth with a large included angle and more gage surface to resist the wear in harder and more abrasive formations. They are particularly efficient in formations where shales, sandy shales, and limestones alternate. Weight can be applied very effectively to these bits due to the more rugged construction of the cutting structure and bearings. However, excessive rotary speeds should be avoided to reduce the shock loads inherent in drilling these harder formations. This is especially important when formations are broken, causing rough operation. You should avoid combinations of weight and rotary speeds which promote rough running to prevent premature failure of bearings and cutting structure. Drilling weights commonly range from 1,000 to 5,000 pounds per inch of bit diameter, with rotary speeds from 60 to 100 revolutions per minute, depending upon the relative weight on the bit.

Hard formation bits Type H, regular circulation steel tooth rock bits are designed to drill hard formations which contain amounts of abrasive materials. Formations requiring the use of this bit type are those having: 1. High compressive strength with low abrasive content such as dolomite. 2. High compressive strength with high abrasive content such as dolomite and trap rock. 3. Medium compressive strength with high abrasive content such as quartz, sandstone and the copper ores. Compared with the soft and medium formation bits, this bit has higher capacity bearings and more closely spaced teeth with increased tooth angles to allow the use of heavier weights required to effectively drill hard formations. The geometry of this bit provides maximum chipping and crushing action with minimum scraping action. The outermost row of teeth on each cone is the driving row; that is, this row generates a rock gear pattern on bottom, which in the case of these strong rocks, is not easily broken up. Because of this, a webbed gage surface is generally used on heel rows of teeth to keep the patterns broken down. Tungsten carbide hardfacing is applied to the “webs” to strengthen the gage against abrasive wear. Type H bits are commonly run with weights ranging from 4,000 to 7,000 pounds per inch of bit diameter with rotary speeds decreasing from 40 to 80 revolutions per minute as weight is increased. Steel tooth Tricone rock bit type vs. rock hardness Rock UCS (PSI)

Steeltooth Tricone bit series

Rock Type

0

2,000

Unconsolidated Sands

S series

Limestone, Siltstone Clay Stone, Mudstone

4,000 Marl, Chalky Limestone

M series 6,000

Soft Shales 8,000

10,000

H series

Consolidated Sandstones Soft Marble, Dolomite

12,000 Tuff, Soft Schist 14,000 Rock UCS hardness (Unconfined Compressive Strength) is only one factor contributing to the “drillability” of any rock. Other factors influencing drillability are fracture toughness, shear strength, Young’s modulus of elasticity, Poisson’s ratio of stress vs. strain & internal angle of friction. Any particular bit may be used in harder or softer rock than this chart indicates.

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Steel tooth bits

Bit specifications

S Series The S series has widely spaced, long tapered teeth with broad, axial crests for the bottom-hole action necessary to achieve high penetration rates. Inter-fitted rows of teeth prevent formation packing and facilitate the cleaning action. The gage bevel is hardfaced for wear resistance. Tungsten carbide hardfacing on the other critical areas of the S series cutting structure provides superior abrasive wear resistance and allows the teeth to self-sharpen. Applications: Softer formations such as clays, shales, soft sandstones, and soft limestones. Suggested Operating Parameters: Weight on Bit – 1,000 to 3,000 lbs per square inch of diameter RPM – 70 to 120 IADC range 1-1-2 to 1-4-2

M Series M series bits are designed with shorter, stronger teeth to withstand the weight required for these formations. The M series shirttail is overlaid with tungsten carbide hardfacing for abrasive wear resistance. Applications: Medium formations, such as limestones, sandstones, and dolomites. Suggested Operating Parameters: Weight on Bit – 3,000 to 5,000 lbs per square inch of diameter RPM – 60 to 100 IADC range 2-1-2 to 2-4-2

H Series H series bits have a heavy gage bevel and short, closely spaced teeth to withstand heavier impact loads. Tungsten carbide hardfacing on the shirttail offers superior wear resistance. The H series has proven successful in drilling operations in which excessive gage wear must be avoided. Applications: Hard shale formations, limestones, sandstones, and dolomite formations. Suggested Operating Parameters: Weight on Bit – 4,000 to 7,000 lbs per square inch of diameter RPM – 60 to 80 IADC range 3-1-2 to 3-4-2

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TCI bit selection Five basic classifications of Atlas Copco Secoroc rock bits are available for TCI (Tungsten Carbide Insert) blasthole drill bits. These are divided into the 40, 50, 60, 70 and 80 series rock bits. The principal design differences are in tailoring the cutting structure of each type to most efficiently drill specific formations. For example, 60 series bits are designed for drilling medium-hard to hard formations, the 70 series for hard formations and the 80 series for the hardest formations. The modifications in cutting structure design from series to series are: 1. The spacing of inserts or teeth is greatest for the softer or weaker formations and decreases as the formation hardness increases. 2. The number of rows and/or the total number of inserts or teeth per bit increases as formation hardness increases. 3. The groove depth and amount of intermesh is decreased as formation hardness increases. 4. The insert or tooth projection above the cone shell is greatest for the softer formations and is decreased as the formation hardness increases.

Bit specifications 50 series

The 50 series bits are typically characterized by more densely spaced chisel or conical inserts. This configuration promotes maximum penetration rates in soft/medium formations that are fractured or have varying degrees of hardness. Applications: Soft/medium formations such as sandstone, shale, granite and some marble. Suggested operating parameters: Weight on bit - 3,000 to 6,500 lbs/inch of diameter Rotations speed - 50 to 150 RPM

Specifications 40 series

60 series

Applications: Soft formations such as shale, siltstone, soft limestone and alluvials.

Applications: Medium/hard formations such as hard limestone, hard shale, basalt and quartzite.

The 40 series bits are typically characterized by large diameter widely spaced super scoop, chisel or conical inserts. The configuration promotes maximum penetration rates in softer formations that have a tendency to stick and ball up the cutting structure.

Suggested operating parameters: Weight on bit - 1,000 to 5,000 lbs/inch of diameter Rotation speed - 50 to 150 RPM

248

The 60 series bits are typically characterized by more densely spaced, shorter projecting chisel, concial or ogive inserts. This configuration promotes maximum penetration rates in medium/hard formations.

Suggested operating parameters: Weight on bit - 4,000 to 7,000 lbs/inch of diameter Rotation Speed - 50 to 120 RPM

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TCI (Tungsten Carbide Insert) bits 70 series

Bit specifications

80 series

The 70 series bits are typically characterized by densely spaced, shorter projecting conical or ogive inserts with a conical or ovoid/ round top gage insert. This configuration promotes maximum penetration rates in hard formations.

The 80 series bits are typically characterized by very densely spaced, short projecting ovoid/round top inserts. This configuration promotes maximum penetration rates in extremely hard formations. Applications: Extremely hard formations such as chert, hematite ore and quartzite.

Applications: Hard formations such as taconite, banded iron and quartzite. Suggested operating parameters: Weight on bit - 4,000 to 8,000 lbs/inch of diameter Rotation speed - 50 to 90 RPM

Suggested operating parameters: Weight on bit - 6,000 to 9,000 lbs/inch of diameter Rotation speed - 40 to 80 RPM

Technical Data Pin connection sizes and make-up torques Bit size range

Connection size

Torque range kilogram force meter

pound force foot

277-346

2,000-2,500

2 3/8

415-484

3,000-3,500

73

2 7/8

622-760

4,500-5,500

89

3 1/2

970-1240

7,000-9,000

mm

inch

mm

73

2 7/8

95-114

3 3/4-4 1/2

60

117-137

4 5/8-5 3/8

143-171

5 5/8-6 3/4

inch

N-Rod* N-Rod*

194-229

7 5/8-9

114

4 1/2

1660-2210

12,000-16,000

251-349

9 7/8-13 3/4

168

6 5/8

3870-4420

28,000-32,000

381-445

15-17 1/2

194

7 5/8

4700-5530

38,000-40,000

*Non-standard API

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Tricone rotary blasthole drilling

Sealed bearing tricone bits represent a technological leap forward over standard “air bearing” roller cone bits. Very high precision machining to very close tolerances, innovative seal technology, premium lubricants, and proprietary materials and processes make these bits more expensive to purchase. These same qualities also provide vastly superior service life and cost savings for the customer. Air bearing bits have existed for the mining industry since the mid 1950’s, when Hughes Tool Company introduced its series of RotoBlast air bearing tricone bits. Built with larger “fit” tolerances and much rougher surface finishes on all bearing surfaces, air bearing bits are therefore significantly less expensive to produce. However, these qualities necessarily give lower service life. Normally between 15% and 30% of the air from the air compressor is diverted into the bit bearings to keep them cool and clean. Bearings are still subject to contami-nation, even while drilling, and therefore may wear rapidly. Sealed bearing bits on the other hand, are made with very close tolerances and extremely smooth bearing contact surfaces. An outer “excluder” keeps contamination (cuttings, grit, and water) out of the bearings under virtually all circumstances, while an inner “seal” keeps grease in the bearings to lubricate the bearing elements. The result is a tricone bit with superior service life without sacrificing productivity (ROP).

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Sealed bearing

The Atlas Copco Secoroc “Omega” sealed bearing product line: • • •

Exceeds air bearing bit performance by a factor of at least 2X, in properly applied situations. Provides a lower Total Drilling Cost where TDC is used as a “value” standard. Provides a lower Cost/Distance where that is the “value” standard.

Patents granted on the most recent competitors sealed bearing bit were very broad and difficult to work around. Their most important patent was on the “excluder”, the outer element that is designed to keep contamination out of, and away from, the actual grease seal. As a result, extensive research into excluder design, and extensive field trials under many different geologic and drilling conditions, resulted in Secoroc being awarded a patent for its’ excluder design. One result however, of greatly increased bit life, is a natural tendency for the ROP to fall below acceptable standards because the bit teeth become increasingly dull with time. “Harder” grades of carbide are required to keep teeth sharp over time, but, harder carbide is more likely to break if drilling conditions become “difficult”. Atlas Copco Secoroc has developed proprietary carbide grades for tungsten carbide inserts used in Omega bits.

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Tricone rotary blasthole drilling

Sealed bearing

A second problem inherent to operating sealed bearing bits is cone erosion. The longer a bit runs, the more cone shell erosion takes place, increasing the likelihood of carbide insert losses. Secoroc’s bit cones are designed for erosion resistance where abrasive conditions are expected.Insert retention is insured with projection ratio’s being considered in all designs.

Product benefits

The Secoroc Omega sealed bearing bit provides better overall value for customers. Lower TDC, higher ROP, longer bit life and the ability to use in variable drilling conditions all contribute to cost savings and profit increases that vary from mine to mine depending on drill depth and patterns. Product features provide cutting structure longevity allowing our customers to significantly reduce bit inventory levels which also effectively reduces shipping, ordering and logistics costs. • • • • • • •

Customers will experience less drilling down time due to fewer bit changes as a result of longer bit life. Customers will achieve a higher rate of penetration with minimal insert breakage, thereby reducing TDC. Sealed bearings last longer than air bearings resulting in more life to the bit and less bit changes. Sealed bearings are not adversely effected by water and corrosion like air bearings. Sealed bearings allow for higher loads of weight and a higher RPM directly effecting TDC. Secoroc Omega’s streamlined lug design occupies less volume in the hole. This increases the total area available at the bit for cuttings to pass through, allowing cuttings to be cleared from the bottom of the hole more efficiently. Secoroc Omega is ideal for drilling conditions where ground water is present in holes or from injected water into air streams, which can be acidic and can nega tively effect bit bearings.

Best Applications

The Secoroc Omega bits have been designed for the most common drilling applications: copper and coal. “44” type testing has taken place in Australia coal mines, while “53”, “54” and “61” types have been tested in copper mines in Peru, Chile, and the United States. 13 ¾" Omega bits are being tested in Canada. • Sealed bearing bit application must, by nature, be selective. • Sealed bearing bits are not appropriate for all drilling applications. • Sealed bearing bits are best applied where bearing failure is the major mode of bit failure. Secoroc Omega is ideal for drilling conditions where ground water is present in holes or from injected water into air streams, which can be acidic and can negatively effect bit bearings. At mines where carbide insert breakage, or cone erosion leading to carbide tooth loss, are the major cause(s) of air bearing bit failures, sealed bearing bits will be of little value. *International Association of Drilling Contractors

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Sealed bearing case study

Newest iteration of bit at 7248 feet with less tooth wear.

US Copper - Largeporphyry deposit drilling

This mine is a large porphyry deposit with extremely varied ground conditions. The mine groups the rock into eight main categories with rock sub-types within each category. What makes the drilling conditions vary so much is not necessarily the parent rock, but the alteration suites that were imposed on the parent rock in the pre-mineral, mineralization and post mineral processes. The Basin and Range type geology of the area is rather simple, stacked and layered sediments of the usual kind, with crustal extension to break things into valley basins and mountain ranges, but then volcanic activity introduced hot, molten, igneous material into it, and varied the geology all together. This mine is a porphyry deposit that has remained more or less intact over the eons, without having a lot of the original deposit eroded away over time. The ore bodies are mostly quartzite and quartz monzonite formations. Many areas of this mine contain high percentages of iron pyrite which has a substantially negative effect on bit life due to its highly abrasive nature. Testing of the 12 ¼ OM54CA has been occurring at this property since the conceptual stages of the Secoroc Omega bits almost a decade ago. Three different bit types are cur-rently used to drill the varying formations at this mine. A 53 type bit is used for a majority of the drilling with 62 type bits being the next most used bit type. A small percentage of their drilling utilizes 72 type bits, but that is usually less than 10% of the total drilling. A 54 type “hybrid” cutting structure has been developed over the past 5 years that is successfully drilling different areas where both 53 and 62 type bits are utilized. This is very important, because if a 53 type bit is installed and the drill then moves to an area in which a harder 62 type bit is needed, the more aggressive bit can be dulled quickly due to cutting structure damage.

252

Case study

Previous iteration of bit at 7318 feet. Note the high wear on the tooth projection.

As is customary in most surface mining environments, the drills at this property frequently move between formations, so it was imperative to develop a cutting structure tough enough to drill a wide range or rock types without sacrificing speed or Rate of Penetration. Omega bit testing in late 2009 yielded results in the range of 2 to 3 times the life of epsilon air bearing direct offsets. The overall, mine wide result was 2.4 times the average air bearing bit life with longer runs in the 20,000 to 30,000 foot range. Even though the overall objective for bit life was achieved, the overall Rate of Penetration, or ROP, was 5% less than the offset bits due to the longer runs. The major factor in the reduced ROP was wear on the insert or tooth projection. A follow up iteration was produced to address this and is currently testing with early results looking promising. None of the bits in recent tests have dulled due to bearing failure as the primary dulling characteristic. The few bearings that have failed are attributed to bit body wear resulting from cutting structure damage. Many times, new bits will start off with a high ROP then begin dropping off as it progresses through its life. The goal for this bit is to have an ROP that is more sustainable over the entire life of the bit. The Secoroc Omega bits can start with a slightly lower ROP than the more aggressive 53 type bits, but has an overall equivalent or higher ROP sustained over the entire bit life providing value to the customer. A study was done in 2008 to determine the annual cost savings associated with fewer bit changes. The study assumed an average bit life for the Omega bit at 2.25 X the standard bit life. This reduces the overall bit usage by 55.6% saving the customer around $51,000 / year in labor costs alone, plus eliminates 340 hours of lost production time per year due to bit changes.

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Tricone rotary blasthole drilling Many times, new bits will start off with a high ROP then begin dropping off as it progresses through its life. The goal for this bit is to have an ROP that is more sustainable over the entire life of the bit. The Secoroc Omega bits can start with a slightly lower ROP than the more aggressive 53 type bits, but has an overall equivalent or higher ROP sustained over the entire bit life providing value to the customer. A study was done in 2008 to determine the annual cost savings associated with fewer bit changes. The study assumed an average bit life for the Omega bit at 2.25 X the standard bit life. This reduces the overall bit usage by 55.6% saving the customer around $51,000 / year in labor costs alone, plus eliminates 340 hours of lost production time per year due to bit changes.

Case study

Cost reduction estimates due to decreased bit changes. Condition being measured Estimated rotary bit usage

Current Mine Usage / Costs

Secoroc Omega Projections

Bit Reduction Usage / Cost Savings by using Secoroc Omega

270 bits

120 bits

150 bits

Average estimated time for bit change

2.25 hours

Average number of employees involved in bit change

2-3

Estimated employee hourly cost

$60

Estimated cost for employees to change a bit Estimated costs to change out a bit

$337.5 $91, 125

$40,500

$50,625

Figures used in this chart are preliminary estimates for reduction in cost due to decreased bit changes. Testing was actually conducted at a US mine using estimations only and does not take into account the cost of the bit. Testing does not take into account that bits removed for size changes can be used again with better performance, since sealed bearing bits do not rust, improving overall performance.

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TCI (Tungsten Carbide Insert) bits

Bit selection

Tricone carbide insert rock bit series vs. rock hardness Rock UCS (psi) 0 4,000

Tungsten carbide insert Tricone bit series

Rock type Claystone, Mudstone

40 series 4-1 to 4-4

Chalky Limestone Soft Shale Loose Sandstones

8,000

Limestone, Siltstone Solid Sandstones

12,000 16,000

50 series 5-1 to 5-4

Medium Shales

MAG NT series

Tuff, Soft Schist Andesite, Rhyolite Quartzite (Sand, Silt)

Omega series

20,000

Limestone, Marble Monzonite, Granite

24,000 28,000 32,000

Gneiss

Epsilon series

Diorite, Diabase Hard Shale, Slate

60 series 6-1 to 6-4

Limestone, Dolomite Basalt Tactite, Skarn

36,000

Granodiorite HD NT series

40,000

Taconite Quartzite Syenite

44,000 48,000

70 series 7-1 to 7-4

Gabbro Banded Iron Formation Taconite

52,000

Chert

56,000

Quartzite

60,000 64,000

80 series 8-1 to 8-4

Amphibolite Hornfels

68,000

Hematite Ore

Higher

“Lava”, Basalt, Biwabic, Quartzite

Rock UCS hardness (Unconfined Compressive Strength) is only one factor that contributes to the “drillability” of any rock. Other factors strongly influencing drillability are: fracture toughness, shear strength, Young’s modulus of elasticity, Poisson’s ratio of stress vs. strain, internal angle of friction. Any particular bit may be used in harder or softer rock than this chart indicates.

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When to change a bit At most mines the decision when to change the bit is typically left up to the driller, with very little guidance given. This results in most bits being changed only after they have been completely worn out. We believe that a typical operation can save $000’s annually by applying some simple rules.

Tricone bits Analyzing a typical bit run Rig cost: $200 Bit cost: $3,550

At the end of a Tricone bits life the cutting structure becomes ineffective either through breakage or wear, resulting in reduced penetration rate. Using the TDC formula, “cost effective” bit life can be calculated and related to penetration rate, giving the drill operator a guide as to when to change the bit.

This bit has too many broken teeth to be effective any longer.

Date

Meters

Hours

ROP

TDC/m

9-Oct

727

9

80.8

$7.36

10-Oct

1,597

20

80.7

$4.70

11-Oct

2,308

29

80.2

$4.03

12-Oct

3,106

38

81.6

$3.59

13-Oct

3,573

46

77.6

$3.57

14-Oct

4,078

54

76.1

$3.50

15-Oct

4,431

58

76.5

$3.42

16-Oct

4,753

62

76.7

$3.35

17-Oct

5,251

70

75.0

$3.34

18-Oct

5,662

76

74.7

$3.31

19-Oct

6,174

83

74.5

$3.26

20-Oct

6,774

91

74.6

$3.21

21-Oct

7,162

99

72.7

$3.25

22-Oct

7,459

107

69.9

$3.33

23-Oct

7,893

117

67.4

$3.41

24-Oct

8,295

127

65.2

$3.51

Analyzing a typical bit run, as shown in the table above, the optimum point in time to pull a bit can be identified. It is seen that had the bit been removed on the 20th of October, the run would have been $0.30 per meter more cost effective than on the 24th October. Based on 250,000 meters drilled annually, the projected savings would be $75,000 per annum.

TDC Penetration Rate

$7.00

- 80.0

- 75.0

$6.00 $5.00

- 70.0

$4.00 $3.00 Optimum time to change bit. Lowest TDC = $3.21 per meter

$2.00

- 65.0

$1.00 - 60.0

8295

7492

7893

7162

6174

6774

5662

5251

4753

4431

4078

3106

3573

2308

727

Worn teeth cannot penetrate the rock, therefore productivity diminishes.

1597

$

Meters Drilled

Blasthole Drilling in Open Pit Mining 255

Penetration rate (m/hr)

$8.00

Rotary drilling TOOLS

How a rock bit drills

Rock failure

Rock cutting, abrasion - vergy small cracks, insert grinds surface.

Rock cutting, spalling starts - enough weight applied to hard rock deeper. Cracks connect. Chips will come free with air blast.

Abrasion

Spalling

This is an illustration of the first phase of rock failure, called the abrasion phase. This is the result of insufficient weight on the bit. The inserts are contacting the rock under very low weight and the resulting action is very similar to placing a knife blade against a grinding stone. The driller can very easily tell when he is in the abrasion phase because the cuttings coming out of the hole will be fine dust.

Here, rotation speed (RPM) is still the same but sufficient weight has been applied to the bit for most effective insert penetration into the formation. Note that the shell of the bit is not against the formation.

Rock cutting, deeper abrasion - deeper cracking, but does not connect. Next cone must crack rock between these teeth. Rock cutting, deep spalling - cracks connecting at deeper levels. Cracks connect bertween teeth and between rows.

Fatigue

Here, more weight has been added to the bit with RPM the same as in the previous illustration. The additional weight has caused some penetration of the inserts into the formation, but not actual failure of the rock. This is called the fatigue phase and again, the driller can easily recognize this phase by checking the returns. Small chips and a high percentage of dust will be coming out of the hole.

In this second illustration, the inserts are loaded under the proper weight to cause the formation to spall. Chips are removed by the circulating air, allowing the cutting structure to advance. Under “load” condition, the bit will drill at maximum efficiency. The driller will note a large amount of chips with very little dust or fines in the returns.

It should be pointed out that rock failure can be accomplished with this type of loading and insert penetration. However, it may require many impacts on the formation to cause the rock to fail. The penetration rate will be considerably less than desired.

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Rotary drilling TOOLS

How a rock bit drills

Cutting efficiency RPM vs ROP

ROP

RPM

Rock cutting, overpenetration - cuttings trapped betwween cone shell and rock. Cannot be blown out by air blast from nozzles.

Excess weight

Once the spalling phase has been achieved, applying additional weight to the bit will only be harmful to drilling efficiency. The additional weight will cause the inserts to bury themselves in the formation. The result is a decrease in penetration rate.

Maximize ROP

With the bit drilling in the spalling phase, it is possible to increase the penetration rate by maintaining the proper weight, while increasing the rotation speed (RPM). The amount of increase possible in the penetration rate is variable and will be determined by the experience of the driller, the capabilities of the drill and the formation characteristics.

Maximum Drilling Efficiency

WOB vs ROP

RPM ROP

ROP

Weight on Bit (Pulldown)

Maximum cut efficiency

With rotation speed (RPM) fixed, this illustration shows the effect of weight increases on the rate of penetration. After the formation has been “spalled” additional weight will reduce or not increase the drilling rate.

Weight on Bit

Maximum drilling efficiency

The preceding charts illustrate: spalling weight plus rotation speed equals penetration rate. Therefore, optimum drilling efficiency may be reached as follows: At a set RPM, determine best weight on bit (WOB) to produce maximum cut efficiency. At the WOB that gives maximum cut efficiency, RPM should be determined to produce best rate of penetration. Note: High rotary speeds do not necessarily produce high penetration rates.

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Rotary drilling TOOLS

Importance of records

Tricone bits

Drilling hours

Bit selection

Keeping complete and accurate records of blast hole bit performance cannot be stressed too much. A careful study of bit records can be of considerable help in determining the proper bit types and best operating conditions to use. The meters drilled by a bit and the penetration rate have long been accepted “yardsticks” for evaluating the performance of a rock bit. However, these are two different units of measure and many erroneous conclusions have been drawn from these two factors alone. It is therefore necessary to combine these two units of measure into one, known as Total Drill Cost per meter or TDC/meter.

A careful study of bit performance records can be of great help in reducing operation costs through selection of the most economical bit types and operating conditions. An actual case in which the performance records and bit selection were given full attention is illustrated in the following example:

Summary of average performance data Bit type Bit cost

Standard product

Premium product

US $2500

US $2875

The Total Drilling Cost is then, the cost of the bit plus the cost of operating the drill.

Meters/bit

5400

5000

Meters/hour

28

32

The simplistic cost/m would use bit cost/meters drilled, indeed this makes up one half of the TDC/m equation. The speed at which the bit drills is included by dividing the cost of the drill/hour by the penetration rate of the bit.

Rig cost/hour

120

120

25000 kg

25000 kg

80-100

80-100

4.75

4.33

Hence: TDC $/m = Bit cost Bit meters

+ Rig cost/hour

Bit drilling speed

It may be seen in the Table below that three bits of type A were run alternatively with three bits of type B. The record indicates that the formation drilled was relatively uniform. Type A average 1418 meters in 27.8 hours; type B averaged 1577 meters in 33 hours. Which bit was most economic if bit costs were the same at US $3000 and rig rate per hour was US $120/hour?

Weight RPM TDC/meter

Analysis of the standard product, indicated that gage row cutting structure was worn, leading to shirttail wear and failure. The premium product, with enhanced tungsten carbide insert features to allow maximum penetration rate was tried. Using the TDC $/m equation introduced earlier and performance data from above, a breakeven graph can be constructed.

Type A bit TDC $/m = $4.47 Type B bit TDC $/m = $4.57 Now the bits can be compared and Type A is the better bit with the lower TDC$/m.

Typical bit performance record Bit type

Meters Hours Rate Weight Rotary drilled run M/hr in Kg RPM

Premium product Soft Med. Hard

A

1907

38.1

50.1

40000

70/90

X

B

1913

39.5

48.4

40000

70/90

X

A

1303

23.9

54.5

40000

70/90

X

B

1485

32.3

46.0

40000

70/90

X

A

1044

21.3

49.0

40000

70/90

X

B

1334

27.3

48.9

40000

70/90

X

Avg. A

1418

27.8

51.1

Avg. B

1577

33.0

47.7

258

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Importance of records

Tricone bits

Drilling hours premium bit breakeven performance

5500 5000 Meters drilled

4500

Step 1

Breakeven Costs

4000 3500

156 hours

3000 2500

       2875        120

3000

Premium bit cost    Rig cost/hour

= Hours (point A) = 24

*Plot to the left of zero on the X axis

1500 1000 500 -25

Step 2  Premium bit cost = Meters (point B) Standard TDC $/m

605 m step 2 (point B) 25

50 75

100

125

150

175

-24 step 1 (point A)

       2875       4.75

= 605

Hours

Step 3

Draw a straight line through points A and B

Bit performance above the line will return a profit for the additional investment in the premium product.

Rotary Tricone Blasthole Drilling Rock Type

All rock types, all rock strengths

Hole Sizes

5 5/8" - 17 1/2" (143 mm - 445 mm)

Hole Depth

10 ft - 250 ft (3.04 M - 76.2 M)

Rate of Penetration, Hole-to-hole

Soft (coal overburden): 100 - 300 M/hr

Hard (iron ore): 20 - 60 M/hr

Straightness of holes

Very good in typical 10 - 20 meter “benching” operations

Suggest using drill string roller stabilizer in long holes for casting or “deep benching” operations

Production Capacity, Typical Tons/ Shift per drill (10 hrs.)

Coal overburden, 7 7/8" (200 mm) bit: 75,000 tons

Iron Ore, 12 1/4" (311 mm) bit: 30,000 tons

Low Fuel Consumption, Ltr/Hr

75 - 90 l/hr small to medium drill (0.01 - 0.012 ltr/t)

100 - 120 ltr/hr medium to large drill (0.03 - 0.04 ltr/t)

Economic Drill String Life, M

300,000 meters/pipe, non abrasive rock

40,000 meters/pipe, highly abrasive pipe

Low Drill String Investment

Yes, relative to size and hole depth

Suitable for Difficult Drilling Conditions

Yes

Suitable for Good Drilling Conditions

Yes

Operator Friendly

Yes, larger drill cabs, more room, more available amenities

Flushing Flexibility

1000 to 4000 CFM, (28.3 - 113.3 cuM/min) depending on drill and bit size. Able to adjust bit air pressure with different nozzles. Compatible with “high pressure” (350 psi/24 bar and higher) air compressors.

Blasthole Drilling in Open Pit Mining 259

Rotary drilling TOOLS

Air practices Air is a critical factor in tricone rotary blasthole drilling performance. Without proper air flow, tricone rotary blasthole bits cannot be operated efficiently. Bit bearings are not kept clean and cool. Cuttings are not blown away from the cutting face of the bit and moved up and out of the hole. The operating cost of drilling a hole increases.

Key Concepts Standard Air

Air is a compressible gas. In air compressor design, air compressor work and air flow calculations, the standard unit of volume is the cubic foot. The standard temperature is 70 degrees Fahrenheit, and the standard elevation is 0 feet, or sea level. Standard atmospheric pressure at sea level is 14.7 psia. The Standard Cubic Foot (SCF) of air has a standard mass of 0.07494 pounds. (Standard density is .07494 lb./cu. ft.) All engineering air flow calculations are based on the Standard Cubic Foot and standard conditions: standard air mass, standard air temperature, and standard atmospheric pressure.

Introduction Whenever ‘standard’ air volumes are calculated, sea level atmospheric pressure, 14.7 psia, must be added to gauge pressure.

Gas Law Physics

Boyle’s Law states that at a constant temperature, the volume of a gas varies inversely with the absolute pressure: P1 x V1 = P2 x V2 Charles’ Law states that at a constant pressure, the volume varies directly with the absolute temperature: V1 x T2 = V2 x T1 Amonton’s Law says that at a constant volume, the absolute pressure varies directly with the absolute temperature: P1 x T2 = P2 x T1 In our work, Boyles’, Charles’, and Amontons’ laws all interact through the Combined Gas Law equation: P1 x V1 = P2 x V2 T1 T2

Air Density and Atmospheric Pressure

Actual Air “Actual” air is the “free” air outside of the drill bit that does the work in drilling. Compressed air does not move cuttings away from the cutting face of the bit. Compressed air does not move rock particles up the blasthole from the bit to the surface. Compressed air must be released to “atmospheric” or “ambient” or “actual” site specific conditions before any work can be done. “Actual” air is derived from “standard” air by applying the Altitude/Temperature factor:

Absolute vs. Gauge Pressure

Pressures are variously reported as “psia” and “psig”. The ending letter, “a” or “g”, refers to whether the pressure being discussed is “absolute” pressure or “gauge” pressure. “Absolute pressure” is the sum of the local ambient atmospheric pressure plus any pressure reading on a pressure gauge. “Gauge pressure” is the pressure indicated by a pressure gauge in the air system.

As altitude increases, the ambient (local) atmospheric pressure decreases. The column of air above that particular point on the earth’s surface is not as deep, therefore it weighs less, and exerts less pressure on that point. This allows the “contents” of a SCF to expand until equilibrium with the new atmospheric pressure is reached. What starts out as one (1.00) standard cubic foot of air becomes larger, because the atmospheric pressure confining it is less. At sea level, atmospheric pressure is 14.7 psia. At 5000 feet, atmospheric pressure drops to 12.23 psia. This allows the same weight of air, .07494 lb. (contained in one cubic foot) to expand into a larger volume. Because it now has a larger volume, the density is less. At 5000 feet, and 70 Deg. F, one (1) ambient cubic foot of air weighs .0623 pounds. The original SCF, weighing .07494 pounds has expanded into 1.202 cubic feet: .07494 lb / .0623 lb = 1.202. Temperature has the same effect on air as does confining pressure (altitude). As temperature increases, the density of air decreases. This can be seen from the gas laws. Conversely, as altitude decreases, air becomes more dense. 1.000 SCF becomes 0.89 SCF at -2,000 feet, and has a density of .0834 pounds per cubic foot.

At sea level and 70o F, a Cab gauge pressure of 37 psig is therefore equivalent to 51.7 psia: 37 psig + 14.7 psi ambient atmospheric pressure = 51.7 psia. At 5000 feet, and 70o F the same cab gauge reading would be equivalent to 49.23 psia: 37 psig + 12.23 psia (atmospheric pressure at 5,000 ft, 70o F) = 49.23 psia. If no “a” or “g” appears after psi, the pressure is taken to mean gauge pressure.

260

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Air practices Altitude/Temperature Factor The A/T factor is used to adjust (“derate”) air compressor intake ratings in response to changes in local altitude and ambient temperature; and to “expand” the calculated compressed air output to local conditions. The A/T factor also helps to calculate the % Capacity of the air compressor during an air compressor volume test; and using the measured delivered SCFM (which may be quite different from the specification volume rating) calculates the Bailing Velocity, Chip Settling Velocity, and the Chip Exit Velocity. For example, the A/T factor for 5,000 feet and 70o F is 1.202. (14.7 psia standard atmospheric pressure at 0 feet /12.23 psia ambient atmospheric pressure at 5,000 feet = 1.202.)

Bailing Velocity

The speed of the actual air moving up a blasthole. A geometrical calculation dependent on bit diameter, drill pipe diameter, and the volume of air circulated through the hole. Bailing Velocity must be higher than Chip Settling Velocity or cuttings will not be transported.

Chip Settling Velocity The velocity a rock chip falling through air wants to achieve. Theoretical values are calculated from an adaptation of Stokes Law. Dependent on cuttings diameter and rock specific gravity.

Chip Exit Velocity The speed the cuttings (chips) move up the hole. The difference between Bailing Velocity and Chip Settling Velocity: CEV = BV - SV.

Tricone rotary blasthole drill air requirements There are two things that clean cuttings from a rotary blasthole and must be combined to make drilling efficient: air pressure and air volume. Air pressure determines the force of the jet nozzle air blast blowing against the bottom of the hole to move cuttings away from the face of the bit.

Air requirements Two other factors that affect the air requirements are the moisture content of the rock and cuttings, and the incidence of fractures and joints. Wet rock, due to ground water or excessive water injection, will be heavier than the same rock when dry. Cuttings from wet rock tend to stick together, making larger particles to be blown from the hole. Fractured or jointed ground will rob air from the blasthole, causing the actual bailing velocity to be lower than the calculated bailing velocity. In both of these instances, the actual air volume required may be much higher than what straight theoretical calculations indicate. Experience is the best guide.

Recommendations: Bailing Velocity

Bailing Velocity is dependent on three things: ACFM (free air), hole diameter, and drill pipe outside diameter. The value normally calculated is a geometric and theoretical value that assumes a perfectly drilled straight hole with no air losses out the side of the holes through cracks and fractures. We must assume this because no one ever measures a blasthole specifically for its diameter. Under normal conditions of dry rock, very light water injection, little or no ground water, and few if any joints or fractures, minimum bailing velocities of 5,000 to 7,000 feet per minute (FPM) can be used. In situations where the rock is a denser, heavier material, velocities up to 9,000 FPM could be used with little problem. In situations where the rock is wet, or dense, or there is a high penetration rate (above 180 feet per hour), bailing velocities of 9,000 FPM or more may be needed. Again, it will depend on individual situations. The overriding recommendation for bailing air is to have a minimum of 1,000 feet per minute Chip Exit Velocity with drill pipe worn to replacement diameter. If this condition is met, bailing performance will be good under all other conditions. Annular pressure calculations will not be discussed here. Once the reader understands the ‘basics’ of compressed air use in blasthole drilling, they should pursue an advanced knowledge of rotary blasthole annular pressures by obtaining those materials from Secoroc in Grand Prairie, Texas, USA. The following discussion of Particle Settling Velocity is intended to illustrate the problems of varying rock densities and chip sizes, and how they affect the rate of chip removal from the drill hole.

Air volume, as bailing velocity, lifts cuttings up out of the hole once they are moved away from the bit face.

Blasthole Drilling in Open Pit Mining 261

Rotary drilling TOOLS

Air practices

Particle settling velocity

Particle Slip (or Settling) Velocity

Cuttings particles fall through air at velocities dependent on particle density, particle diameter and shape, and air density. Large, heavy particles fall faster than small, light ones. “Slip velocity” is the speed at which a particle falls through still air. It is also called settling velocity. Slip velocities in air may be much higher than one would expect. If the bailing velocity in a hole is not greater than the slip velocity of a given size particle, that particle will not be carried from the hole. It will be reground until it is of a small enough size to be carried out by the air stream. Remember: bigger chips indicate more efficient drilling, and yield faster penetration rates. The following particle slip velocity equation is from Walker and Mays, Journal of Petroleum Technology, July 1975. Particle Slip Velocity Vt = {(2G x dp x (DenP - DenF)) / (1.12 x DenF)}.5

Where:

Vt = Terminal Slip Velocity of particle, ft / sec G = Gravity, 32 ft / sec2 dp = Diameter of Particle, feet DenP = Density of Particle, lb / cubic foot DenF = Density of Fluid, lb / cubic foot

Sufficient air pressure at the bit must be present to insure that plenty of air is going through the bit bearings. Bearing air is necessary to: 1) keep the bearings cool, and 2) keep the bearings clean. Hot and/or dirty bearings will cause early bit failure. With air pressure systems whose minimum operating pressure is greater than 35 psig, Atlas Copco Secoroc generally recommends bit pressures of 40 psig to 45 psig minimum. This range has been found to provide enough pressure in the bearings to keep them clean and cool, and still direct plenty of air through the nozzles for good bottom hole cleaning. The Atlas Copco Drilling Solutions blasthole drill air compressor is normally capable of generating 110 psig at the receiver tank. Because of the higher level of air pressure available on these drills for tricone drilling, Secoroc suggests that tricone bit pressures can be in the 60 - 65 psi range without causing any problems. Full volume will be delivered as long as the air compressors are properly adjusted, and operating to their specified parameters.

Nozzle Selection Bearing Life

Given: Chip diameter = .125”, .25”, .50” DenP =

145 lb / ft3 for Sandstone 168 lb / ft3 for Granite 181 lb / ft3 for Dolomite

DenF =

.07651 lb / ft3 for air at sea level and 59o F

Terminal Settling Velocity, feet / minute: Also take into consideration that as altitude increases, air density decreases; thus, particle slip velocity will increase. Moving from sea level to 5,000 feet, air density drops to .0637 lb/cu ft. The settling velocity of a 1/2 inch chip of granite increases from 4330 ft to 4755 ft. It can now be seen that chips do not leave the hole at the calculated bailing velocity, and that loss of air from any part of the hole can reduce the actual bailing velocity to below the settling velocity of the chips the bit actually generates. Recommended bailing velocities of 5,000 FPM are a minimum recommendation!

Chip Diameter

Sandstone

Granite

Dolomite

1/8”

2013

2166

2249

1/4”

2847

3064

3181

1/2”

4031

4339

4503

262

Bit Pressure Drop

Bearing life can be increased by using smaller nozzles in the bit. With smaller nozzles, proportionally more air is forced through the bearing system, providing more cleaning and cooling. Dulling characteristics of bits should be determined. If shirttail erosion and exposure or loss of outer bearings is common, increased air through the bearings will probably help bearing life by keeping the cone backface and shirttail lip cleaner. If bit failure is not due to an erosive bearing failure (such as described above), and the cutting structure is not highly damaged or eroded, smaller nozzles could again help by forcing more air through the bearings. In this instance, however, it is the cooling of the bearings that is being enhanced. As the bearings rotate under load, heat is generated. Too much heat build up causes thermal degradation of the bearing metal. The air in the bearings still retains some of the heat gained during compression, and may not provide enough cooling capacity at low pressures (and flow rates) for the bearings. At higher pressures, the cooling capacity of the air is increased due to the increased volume passing through the bearings, so the bearings stay cooler, prolonging their life.

Bottom Hole Cleaning

Bottom hole cleaning is a function of the “force” or “power” the air blast exerts on the bottom of the hole. Two things must happen. First, there must be enough power exerted on the cuttings to dislodge them from their position on the hole bottom. Cuttings may be Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Air practices

Force exerted by air

laying loose on the bottom, or they might be partially or completely trapped under a layer of crushed material. Second, the cuttings must be transported out from under the bit. The first situation, freeing the cuttings, requires more “power” than transporting the cuttings. Once cuttings are loose, they are relatively easily transported. In the “Force Exerted By Air Calculation” to the right, the force of air leaving a bit nozzle is calculated. Pressures and temperatures are actual parameters found on a drill equipped with a two-stage compressor. Air volume is converted to weight. Air velocity at nozzle exit is calculated. Multiplying the air discharge in “pounds per second” by the air velocity in “feet per second” gives the quantity “pound feet/sec2”.This converts to a measure of force, kg meter / sec2, the “Newton”. The calculations are all at “Standard Conditions”. In the “Force Exerted by Air Calculation”, it can be seen that smaller nozzles will apply more force to the hole bottom for cleaning. The added benefit is increased air through the bearings, keeping them cleaner and cooler.

the variations of the coefficient of flow for the orifices. The above flows were calculated with a .80 coefficient of flow. If the coefficient was .78 for 1/2” and .82 for 5/8”, the flows would be virtually identical. The actual air test was done with 7/8”, 1”, and 1 1/8” orifices. With a coefficient of .78, calculated dSCFM’s for the orifices were 796.9, 796.5, and 797.2 SCFM respectively. No real change from small to large. Caution is advised. Although the volumes changed very little, the amount of force increases with velocity. The increased scouring action, if carried to an extreme, could result in increased erosion of the bit. The increased blast will carry cuttings at a higher velocity, possibly to the detriment of the bit. This can be especially true if penetration rates are high and cuttings are abrasive. Keep in mind that 30% to 50% of the air in a bit goes through the bearings, and is not used to clean the bottom of the hole. Only with adequate pressure in the bit can you move cuttings out before they can be reground. Increased force on the bottom of the hole will give better cleaning. Better cleaning equals higher ROP. Higher ROP equals a lower Total Drilling Cost.

Force Exerted by Air Calculation Given 1/2”

9/16”

5/8”

Nozzle Diameter

79 psig

57 psig

42 psig

Tool Air Pressure

117º F

117º F

117º F

Tool Air Temperature

260 CFM

252 CFM

246 CFM

dSCFM

Calc./Nozzle (CFM) / 60) x .07494 = lb per second CFM / 60 / Nozzle area (sq. ft.) = Air velocity, ft/sec lb/sec x ft/sec = lbft/sec2 Calculate 1/2”

9/16”

5/8”

.3250 lb/sec

.3157 lb/sec

.3072 lb/sec

3089.5 ft

2470.5 ft

1952.6 ft

138 N

107 N

82 N

Nozzle Diameter Air Weight Delivered Air Velocity Newton’s Force/ Nozzle

1 lb ft / sec2 = .1382 kg meter / sec2 1 kg meter / sec2 = 1 Newton

Something is seen in this calculation that runs contrary to popular wisdom. As nozzle size increased, the volume and weight of air delivered decreased. This can be attributed to inaccuracies in air temperature, air pressure, and Blasthole Drilling in Open Pit Mining 263

Rotary drilling TOOLS

Air practices

Suggested nozzle sizes

Suggested Nozzle ID Sizes for Secoroc Tricone Rotary Blasthole Bits Nozzle ID Calculations use the following as constants: • Suggested Bit Pressure of 65 psi for Atlas Copco Drills only (pressure at Cab Gauge will be higher). • 110 °F delivered bit air temperature • 70 °F air compressor intake temperature Enter Altitude of Drill Site in Feet: 1000 Meters x 3.28 = Feet





A/T Factor: 1.057

Air Compressor Intake Rating - CFM Bit Diameter inches

mm’s

750

900

1050

1200

1400

1900

2600

3800

inches

mm’s

inches

mm’s

inches

mm’s

inches

mm’s

inches

mm’s

inches

mm’s

inches

mm’s

inches

mm’s

5 5/8

143

1/2

12

1/2

13

9/16

14

5/8

16

11/16

17

3/4

20

15/16

23

1 1/8

28

5 7/8

149

7/16

12

1/2

13

9/16

14

5/8

15

11/16

17

3/4

20

15/16

23

1 1/8

28

6

152

7/16

12

1/2

13

9/16

14

5/8

15

5/8

17

3/4

20

15/16

23

1 1/8

28

6 1/4

159

7/16

12

1/2

13

9/16

14

5/8

15

5/8

17

3/4

20

15/16

23

1 1/8

28

6 3/4

171

7/16

11

1/2

13

9/16

14

9/16

15

5/8

16

3/4

19

15/16

23

1 1/8

28

7 3/8

187

7/16

11

1/2

13

9/16

14

9/16

15

5/8

16

3/4

19

7/8

23

1 1/8

28

7 7/8

200

7/16

11

1/2

12

1/2

13

9/16

14

5/8

16

3/4

19

7/8

23

1 1/16

28

8 1/2

216

3/8

9

7/16

10

1/2

12

1/2

13

9/16

15

11/16

18

7/8

22

1 1/16

27

9

229

3/8

9

7/16

10

1/2

12

1/2

13

9/16

15

11/16

18

7/8

22

1 1/16

27

9 7/8

251

1/4

6

5/16

9

3/8

10

7/16

12

1/2

13

11/16

17

13/16

21

1 1/16

26

10 5/8

270

1/8

4

1/4

7

3/8

9

7/16

10

1/2

12

5/8

16

13/16

20

1

26

290 mm

290

X

X

1/4

6

5/16

8

3/8

10

7/16

12

5/8

16

13/16

20

1

26

11

279

X

X

1/4

6

5/16

8

3/8

10

7/16

12

5/8

16

13/16

20

1

26

12 1/4

311

X

X

1/4

6

5/16

8

3/8

10

7/16

12

5/8

16

13/16

20

1

26

13 3/4

349

X

X

X

X

3/16

6

5/16

8

3/8

10

9/16

15

3/4

19

1

25

15

381

X

X

X

X

3/16

4

1/4

7

3/8

10

9/16

14

3/4

19

1

25

16

406

X

X

X

X

X

X

3/16

5

5/16

8

1/2

13

11/16

18

15/16

24

17 1/2

445

X

X

X

X

X

X

X

X

3/16

5

7/16

12

11/16

17

15/16

23

CO P O ly C AS s On L AT ill Dr

264

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Air practices (other brand drills)

Suggested nozzle sizes

Suggested Nozzle ID Sizes for Secoroc Tricone Rotary Blasthole Bits Nozzle ID Calculations use the following as constants: • Suggested Bit Pressure of 45 psi for other brand drills only (pressure at Cab Gauge will be higher). • 110 °F delivered bit air temperature • 70 °F air compressor intake temperature Enter Altitude of Drill Site in Feet: 1000 Meters x 3.28 = Feet





A/T Factor: 1.019

Air Compressor Intake Rating - CFM Bit Diameter

900 inches

1200 mm’s

inches

1600

inches

mm’s

mm’s

5 5/8

143

X

X

X

X

5 7/8

149

5/8

16

3/4

18

inches

2000

2500

3000

mm’s

inches

mm’s

inches

mm’s

X

X

X

X

X

13/16

21

X

X

X

3600

3800

inches

mm’s

inches

mm’s

inches

mm’s

X

X

X

X

X

X

X

X

X

X

X

X

X

X

6

152

5/8

16

3/4

18

13/16

21

X

X

X

X

X

X

X

X

X

X

6 1/4

159

5/8

16

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

6 3/4

171

5/8

15

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

7 3/8

187

5/8

15

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

7 7/8

200

9/16

15

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

8 1/2

216

9/16

14

5/8

17

3/4

20

X

X

X

X

X

X

X

X

X

X

9

229

9/16

14

5/8

17

3/4

20

7/8

23

1

26

X

X

X

X

X

X

9 7/8

251

1/2

12

5/8

15

3/4

19

7/8

22

1

25

X

X

X

X

X

X

10 5/8

270

7/16

11

9/16

14

11/16

18

13/16

21

15/16

24

X

X

X

X

X

X

290 mm

290

7/16

10

9/16

14

11/16

18

13/16

21

15/16

24

X

X

X

X

X

X

11

279

7/16

10

9/16

14

11/16

18

13/16

21

15/16

24

X

X

X

X

X

X

12 1/4

311

7/16

10

9/16

14

11/16

18

13/16

21

15/16

24

1 1/16

27

1 3/16

30

1

31

13 3/4

349

5/16

9

1/2

13

11/16

17

13/16

20

15/16

23

1 1/16

26

1 3/16

30

1

31

15

381

5/16

8

1/2

12

5/8

16

3/4

20

15/16

23

1

26

1 1/4

29

1

30

16

406

1/4

6

7/16

11

5/8

16

3/4

19

7/8

23

1

26

1 1/4

29

15/16

30

17 1/2

445

1/4

6

3/8

9

9/16

14

11/16

18

7/8

22

1

25

1

28

15/16

29

nd a br nly er s O h Ot rill D

Blasthole Drilling in Open Pit Mining 265

Rotary drilling TOOLS

Air requirements and nozzle selection In rotary blasthole drilling, there is always a concern with delivery of air in sufficient volume and at the proper pressure to assure optimum bit performance when drilling with recommended bit weight and RPM. Sufficient air volume should be provided to produce an annular return velocity of 5,000-7,000 ft./min. for light, dry materials; and 7,000-9,000 ft./min. for materials that are wet and/or heavy, and when drilling at penetration rates of 35 m per hour or higher. To determine volumetric requirements, the simple Flow equation Q = AV may be used. Since friction losses in the annulus of relatively shallow holes of blasthole drilling are negligible, this becomes: Q=

V 183.35

Air Volume requirements for various hole diameter and drill pipe combinations - for 5,000 ft. and 7,000 ft. per min. annular velocity D. hole diameter (in)

D. pipe O.D. (in)

Q. - 5,000 CuFt/ min free air

Q. - 7,000 CuFt/ min free air

2 7/8

327

458

4 1/2

3 1/2

218

305

4

116

162

2 7/8

390

546

3 1/2

282

395

4

178

249

2 7/8

491

687

3 1/2 4

382 280

535 392

2 7/8

637

892

3 /12

530

742

4

426

596 1,025

4 3/4

5 1/8

5 5/8

(D2 - d2) 6 1/4

The table on this page shows volumetric requirements in cubic feet of free air per minute necessary to provide both 5,000 and 7,000 ft. per min. annular velocity for various possible combinations of hole size and drill pipe size.

6 3/4

The equation used is the simple flow equation: Q = AV. 7 3/8

With all constants combined and area expressed as difference between hole and pipe areas, this equation becomes: Q = 27.27 (D2- d2). • Q = cubic feet per minute free air necessary to obtain 5,000 feet per minutes annular velocity

7 7/8

• d = drill pipe outside diameter, inches • D = hole diameter, inches

9

Should Q be desired for some annular return velocity “V” other than 5,000 feet per minute, the result obtained above or from the table should be multiplied by the factor: V/5000.

9 7/8

Example: A 9 7/8” hole being drilled with 7 3/4” drill pipe at a desired annular velocity of 5,000 ft. per minute. Solution: Q = 27.27 [(9 7/8)2 - (7 3/4)2] = 27.27 [97.52 - 60.06] = 1022 cu. ft. per min. (shown in table) Had 7,000 ft. per min. velocity been desired: Q = (1022)

V7000 5000

= 1431 cu. ft. per min.

The above equation may also be rewritten to solve for annular velocity “V” when available compressor capacity, hole size and pipe size are known. V (ft./min.) =

266

183.35Q (D2 - d2)

Tricone bits

11

12 1/4

13 3/4

15

17 1/2

3 1/2

732

4 1/2

513

718

5

382

535

3 1/2

908

1,271

4

805

1,127

4 1/2

690

966

5

560

784

3 1/2

1358

1,900

4 1/2

932

1,305

5 1/2

658

921

3 1/2

1358

1,900

4 1/2

1138

1,503

5 1/2

867

1,214

6 1/2

625

875

6 5/8

493

690

7

355

497

4 1/2

1665

2,331

5 1/2

1383

1,936

6 5/8

1063

1,488

7

873

1,222

7 3/4

570

798

7

1323

1,852

7 3/4

1022

1,431

8 5/8

627

878

9

450

630

7

1964

2,749

7 3/4

1662

2,323

8 5/8 9

1272 1090

1,779 1,526

8 5/8

2063

2,888

9

1882

2,635

10

1365

1,911

10 3/4

941

1,317 3,400

10

2429

10 3/4

2004

2,806

10

3409

4,772

10 3/4

2985

4,179

12

2209

3,093

13

1527

2,138

10

3743

5,240

14 16

3007 1370

4,210 1,918

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Air requirements and nozzle selection Nozzle size selection Nozzles should be selected so that the pressure inside the bit is 40-45 psi. The cab operating pressure will be somewhat higher, depending on the type of drill and CFM of air circulated. Typically, on compressors rated at 65 psi, pressure inside the bit will be 8-15 psi lower than what the cab gauge shows. On drills with 80-100 psi rated compressors, bit pressures can be 25-50 psi lower than the cab gauge reading. The proper procedure for determining the correct nozzle size is as follows: 1. Remove the bit and perform an air test. Record all pressure readings. Be sure to use at least one orifice plate in the air test that will give 40-45 psi at the tool. 2. Determine what the cab pressure is when the tool pressure is 40-45 psi. 3. Re-install the bit with the original nozzles. Run the air compressor and record the cab air pressure. 4. If you do not get the cab air pressure that you saw with 40-45 psi tool air pressure during the air test, continue to install and check different sets of nozzles in the bit until you do get the cab pressure that cor- responds to 40-45 psi in the tool. 5. Once you get the same cab air pressure with nozzles that you got during the air test with 40-45 psi tool pressure, you have found the correct size nozzles to use in the bit.

Tricone bits

How to remove and install air blast nozzles Nozzle removal 1. Use a screwdriver to pry up the head of the nail locking the nozzle into place. 2. When the nail head is pried up, grab the nail with pliers and pull the nail completely out of the bit. 3. Remove the nozzle

Nozzle installation 4. Put the nozzle into the nozzle boss, with the beveled edge to the inside, the flat end to the outside. Place a nozzle nail into the nozzle hole. 5. With a hammer, pound this nozzle nail down until the nail head contacts the bit. 6. DO NOT flatten the head of the nozzle nail against the bit.

The table on the previous page shows approximate bit air pressure that can be expected with the listed nozzles and CFM. This can be used as a starting point for determining correct nozzle size.

Blasthole Drilling in Open Pit Mining 267

Rotary drilling TOOLS

Air requirements and nozzle selection Procedure for using pressure drop tables



1. Establish maximum operating pressure and air volume delivered for the air compressor being used. Consideration should be given to altitude, volumetric efficiency, ambient temperature and mechanical con dition of the compressor when establishing these val ues if actual volume in not known. NOTE: An air test is the best way to determine actual delivery of air volume and pressure. 2. From the table, choose the “air volume delivered” column nearest the actual volume established under item 1. 3. Proceed down the proper “air volume delivered” column to the “bit size range” for the bit being used. 4. Read the air pressure required for forcing air through the bit. The pressure required depends on the size of the air blast nozzles. 5. Select the smallest nozzle diameter available within the given bit size range that can be used without exceeding the maximum operating pressure of the compressor. Note that 10-50 psi should be reserved for a safety buffer and other pressure losses in the system depending on drill type and manufacturer. Example 1 a. Bit size: 7 7/8” b. Air volume delivered: 900 cfm c. Maximum operating pressure rig: 65 psi From the table, select 7/16” nozzle (49 psi), this allows 16 psi for safety buffer and system losses.

Bit size range

5” to 6”

6 1/4” to 7 3/8”

API Pin size

2 7/8” 3 1/2”

3 1/2”

Air course size 3 each

5/16” 3/8” 1/2” 9/16”

               200

300

400

500

600

10

22

47

62

77

16

35

47

59

10

25

35

45

18

26

34

11

18

24

5/16”

42

52

62

3/8”

33

43

51

7/16”

27

34

41

1/2”

23

29

33

9/16”

18

23

29

3/8”

27

36

45

7/16”

21

1/2” 7 7/8” to 9”

4 1/2”

28

35

21

27

9/16”

20

5/8” 11/16” 3/4” 3/8”

26

36

46

7/16”

19

27

35

1/2”

21

9/16” 9 7/8” to 11”

6 5/8”

5/8” 11/16” 3/4” 7/8”

Example 2 a. Bit size: 9” b. Air volume delivered: 1200 cfm c. Maximum operating pressure rig: 50 psi From the table, select 11/16” nozzle (39 psi)

1” 7/16” 1/2” 9/16”

Actual air volumes delivered to the bit is a key factor in preventing early bearing failure and providing proper cleaning of the tool. Pressure drops listed above are approximate for use as guidelines only. Actual pressures will depend on bit condition, bearing type, and air piping conditions. Please contact your Atlas Copco Secoroc representative for assistance in determining the best nozzle size for individual bits and mine site condition.

268

27 20

5/8” 12 1/4” to 15”

6 5/8” to 7 5/8”

11/16” 3/4” 7/8” 1” 1 1/8” 1 1/4”

Blasthole Drilling in Open Pit Mining

19

   

Rotary drilling TOOLS

Tricone bits Nozzle selection

    Air pressure drop across Atlas Copco Secoroc blasthole bits with various nozzle size. Air volume delivered - cubic feet per minute 700

800

900

1000

1100

1200

1300

55

65

75

42

50

58

66

74

31

38

44

58

58

72

81

61

69

78

48

57

65

73

79

41

48

54

61

34

41

47

51

55

66

75

83

42

49

55

33

39

45

26

32

21

26 20

1400

1500

73

79

1600

1700

1800

64

71

67

73

79

56

62

67

63

69

75

81

51

59

67

76

84

37

43

49

55

61

67

73

80

31

36

41

47

52

57

62

25

29

34

39

44

50

21

25

29

34

37

41

1900

69

73

79

55

60

65

71

77

47

51

55

60

65

2000

2100

2200

70

75

79

2300

2400

2600

2800

3000

71

54

62

70

77

42

50

58

65

72

79

33

39

45

53

60

66

71

77

26

32

38

43

49

54

59

64

68

73

78

19

25

32

36

41

46

49

53

58

62

66

70

74

78

20

24

29

34

39

43

47

51

54

58

62

66

70

74

78

19

22

26

31

36

40

43

47

50

54

57

61

64

68

71

75

79

20

24

26

30

32

35

38

41

44

46

49

52

55

59

63

69

75

19

21

23

25

28

30

33

35

38

40

42

47

52

57

46

53

58

63

69

75

25

30

35

41

18

23

27

33

38

43

47

52

56

60

65

70

75

19

23

27

31

34

38

42

46

50

55

59

63

67

72

19

22

25

27

31

34

38

42

46

49

53

57

61

64

68

72

20

23

26

29

32

35

39

42

45

48

52

55

58

62

66

70

19

22

25

28

31

34

37

40

42

45

48

51

53

57

61

65

17

19

21

23

25

27

28

30

33

35

37

40

42

44

47

17

19

21

23

25

27

29

33

37

41

17

19

21

25

27

29

31

17

19

23

25

Above pressure drops are for bits without anti-backflow valves. For bits with anti-backflow valves, add 3 psi.

Blasthole Drilling in Open Pit Mining 269

Rotary drilling TOOLS

Rock formation & drillability General rock characteristics From the stone age until the present time, man has worked to improve his ability to drill holes in “rock”.The term “rock” generally refers to all the material that forms the essential part of the earth’s solid crust, and includes loose, incoherent masses as well as the very firm, hard and solid masses. Most rocks are aggregates of one or more minerals and are most readily classed according to their method of origin, as igneous, sedimentary or metamorphic.

Tricone bits

periodotitie, are less abrasive, but because of the interlocking nature of the ferro-magnesium minerals, tend to be tougher rocks to drill in spite of the fact they are “softer” and less abrasive. If silicified, (silica has been introduced into the rock through alteration processes) igneous rocks of both extrusive and instrusive types can be very difficult to drill. It is very common for extrusive igneous rocks (volcanics to be silicified.

Sedimentary rocks Igneous rocks Extrusive igneous types: rhyolite, andesite, basalt, dacite, latite, tuff, agglomerate Intrusive igneous types: granite, monzonite, granodiorite, diorite, gabbro, peridotite, syenite Igneous rocks form by solidification from a very hot, molten mass called magma, either on the earth’s surface or below it. Igneous rocks (where they have not been altered after their formation by weathering or other chemical action) can be very hard and tough and possess low porosity. There are two main classes of igneous rocks: “extrusive” and “intrusive”. “Extrusive” igneous rocks are those rocks that are expelled onto the surface of the earth by volcanic activity. Common rocks of this type are basalt, andesite, rhyolite, and latite. “Ash flows” from the rock type called “tuff”. “Agglomerate” is a volcanic rock made up of fragments of other rocks that have been picked up and transported by molten lava as it flows over the land surface. “Extrusive” igneous rocks will generally have a very fine crystalline structure due to the fact that they cooled rapidly from the original molten rock. “Intrusive” igneous rocks are those rocks that solidify below the surface of the ground. They will generally have a coarse crystalline structure. Intrusive rocks that cooled very slowly will have the largest crystal structure, while those that cooled more quickly will have a smaller crystal structure.

Types: conglomerate, sandstone, siltsone, claystone, mudstone, shale, graywacke, limestone, dolomite, coal, phosphate rock, iron formation Sedimentary rocks are formed by an accumulation of sediments in water or air. These sediments may consist of rock fragments or particles of various size, shape and chemical composition to form conglomerate, graywacke, sandstone, siltstone, shale, claystone and mudstone in order of decreasing grain size and roughly in order of decreasing rock hardness. Coal and lignite are formed by the compaction and decomposition of plants which accumulated in tropical swamps. Certain limestones and dolomites are formed from the underwater accumulation of animal remains such as coral and shellfish. Sedimentary rocks also form as the product of chemical action or evaporation. Rocks of this origin include limestone, dolomite, phosphate rock and a variety of salts. Chemically deposited limestone and dolomite can be very “tough” rocks to drill. Iron formation is a “catch-all” term for hard, layered, tough, brittle, very fine grained iron bearing rocks that include taconite, banded iron formation and cherty iron formation. It is of sedimentary origin, occurring throughout the world, and is the source rock for most of the word’s iron ore. Iron formations and their altered or enriched equivalents constitute some of the most difficult of all rocks to drill.

Igneous rocks and their drillabilities Igneous rocks are usually difficult to drill especially where they are fresh and unaltered by weathering or alteration. Low drill bit life and low penetration rates are the general rule (as compared to most common sedimentary rocks). In general, igneous rocks high in quartz contents, i.e., the granite-diorite group, are very hard, brittle and abrasive. Those that contain less quartz and more ferr-magnesium minerals, i.e., gabbro, basalt or 270

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Rock formation & drillability

Tricone bits

Metamorphic rocks Types: slate, quartzite, marble, hornfels, schist, gneiss Metamorphic rocks are formed by the action of heat, pressure, and chemical action on pre-existing rocks of any type. Generally, some change in chemical composition has taken place from the original as a result of the heat, pressure, and introduced chemical constituents. Metamorphic rocks can range from very coarse grained to extremely fine grained, depending on the degree of metamorphism. Argillite results from very mild metamorphism of shale, mudstone or claystone. Slate results from an increased level of metamorphism on those same rocks. Quartzite can be formed from sandstone, graywacke or arkose. Quartzite is formed when silica is introduced into sandstone and/or siltstones, and cements the individual grains together. Marble is derived from limestone or dolomite, and is a recrystallization of the original structure. Hornfels is a term applied to fine-grained rocks formed by intense contact metamorphosis (heat, pressure, introduced chemicals) at the borders of igneous rock masses. Hornfels are massive rocks unlike schist or gneiss described below. Schist is a low grade “regional” metamorphic rock which has foliated structure and can be split into thin plates. Some of the original structure of the rock may still be present. There can be mineral segregation, where some minerals may occur in bands, where they did not occur in bands and in the original rock. Gneiss is a high grade to very high grade “regional” metamorphic rock that is generally coarse-grained and banded, in which the bands alternate between “mafic” (iron rich) minerals and “felsic” (non iron) minerals. Similar to various igneous rocks in that they are crystalline and have some of the same mineral constituents, metamorphic rocks are usually difficult to drill. This is caused not only by the hardness and character of the various metamorphic minerals, but by the general interlocking character of mineral crystals which produces a tough rock, difficult to spall.

Rock drilling characteristics General Each of the many types of igneous, sedimentary and metamorphic rocks has its own particular drilling characteristics produced by its mineral composition and grain size. Other factors greatly affecting rock drillability are: rock joints or fractures, bedding or other types of foliation and alteration, which may be simple surface weathering or very complicated chemical alteration processes

such as those which usually are associated with porphyry copper ore bodies. Rock joints occur in virtually every known rock type. Essentially, it is a plane of weakness along which rock tends to break. It can be seen in most quarries and mines. Rock can also be fractured in locations adjacent to blasted areas in mines and quarries. Whatever the agency that causes them, fractures in rock are detrimental to blast hole drilling. They can “rob” return air from the drill hole, thereby reducing ability of the return air supply to remove cuttings from the drill hole; secondly, fractured rock may need to be drilled with less than optimum down pressure and/or rotation speed in order to prevent tooth or insert breakage. Rock drillability can be considerably affected by the angle at which a drill bit intersects bedding or schistosity planes. Drilling in directions parallel to bedding/schistosity planes will usually produce a higher drilling rate and less bit wear than drilling at an angle to bedding/schistosity. Alteration of rock by surface weathering can be seen in most mines and quarries. This process can change a very hard rock such as a granite into a crumbly sandstone. It is caused largely by the action of oxygen, carried by surface water or ground water, on the component minerals of rocks and can extend to depths of 100 m plus. Alteration associated with metallic ore bodies can also affect rock drillabilities by changing the mineral composition of the rock. In general, chemical alteration produces a rock which is softer than the original rock.

Blasthole Drilling in Open Pit Mining 271

Rotary drilling TOOLS

Rock mechanics data Rock

Amphibolite

Specific gravity

Coompressive strength, UCS Psi

Mpa

3.07

61,335

Poisson’s ration stress vs. strain

Tricone bits Modulus of rigidity

Engineering classification of intact rock

Young’s modulus of elasticity

Psi

Mpa

Psi

GPA

423

6,641,000

45,800

15,080,000

104.0

Based on UCS strength A, very high

Based Young’s compressibility 1 - low

Andesite

2.81

26,535

183

3.944.000

27,200

9,367,000

64.6

B, high

2 - medium

Argillite

2.81

19,720

136

-

-

12,194,500

84.1

B, high

1 - low

Basalt

2.94

44,950

310

4,596,500

31,700

11,295,500

77.9

A, very high

2 - medium

Chert, dolomitic

2.67

29,290

202

3,436,500

23,700

8,149,000

56.2

B, high

2 - medium

Conglomerate

2.67

23,925

165

4,698,000

32,400

11,295,500

77.9

B, high

2 - medium

Diabase

2.94

46,545

321

5,408,500

37,300

13,891,000

95.8

A, very high

1 - low

Diorite

3.01

39,730

274

0.29

6,119,000

42,200

15,515,000

107.0

A, very high

1 - low

Dirorite, augite

2.74

48,285

333

0.25

4,886,500

33,700

12,194,500

84.1

A, very high

1 - low

0.14

Dolotmite

2.60

18,995

131

0.18

2,900,000

20,000

6,902,000

47.6

B, high

2 - medium

Gabbro

3.00

44,805

309

0.33

6,394,500

44,100

17,255,000

119.0

A, very high

1 - low

Granite

2.66

37,700

260

0.2

3,422,000

23,600

8,584,000

59.2

A, very high

2 - medium

Granite, aplitic

2.65

51,185

353

0.26

4,756,000

32,800

11,687,000

80.6

A, very high

2 - medium

Granite, gneissic

2.66

30,305

209

0.02

1,299,200

8,960

2,697,000

18.6

B, high

3 - high

Granite, pre-Cambrian

2.80

-

-

0.27

7,583,500

52,300

11,904,500

82.1

-

2 - medium

Granodiorite

2.74

36,540

252

0.24

4,060,000

28,000

9,947,000

68.6

A, very high

2 - medium

Greenstone

3.02

39,005

269

6,104,500

42,100

15,225,000

105.0

A, very high

1 - low

Hematite ore

5.07

88,015

607

-

-

29,000,000

200.0

A, very high

1 - low

Hornfels

3.19

77,285

533

5,930,500

40,900

13,891,000

95.8

A, very high

1 - low

Limestone

2.68

22,330

154

0.28

3,842,500

26,500

9,874,500

68.1

B, high

2 - medium

Limestone, chalky

1.89

4,205

29

0.02

780,100

5,380

1,609,500

11.1

D, low

3 - high

Limestone, dolomitic

2.78

28,710

198

0.29

5,452,000

37,600

14,094,000

97.2

B, high

1 - low

Marble

2.72

23,925

165

0.3

4,393,500

30,300

11,397,000

78.6

B, high

2 - medium

Marble, taconite

2.71

9,005

62

-

-

6,945,500

47.9

C, medium

2 - medium

Marlstone

2.31

21,895

151

0.11

1,609,500

11,100

3,610,500

24.9

B, high

3 - high

Meta-rhyolite

2.84

18,125

125

4,582,000

31,600

11,397,000

78.6

B, high

2 - medium

Monzonite, Quartz

2.68

22,475

155

-

-

10,498,000

72.4

B, high

2 - medium

Phyllite, green

3.24

18,270

126

4,756,000

32,800

11,092,500

76.5

B, high

2 - medium

0.22

Quartzite

2.65

54,230

374

0.13

4,466,000

30,800

10,150,000

70.0

A, very high

2 - medium

Quartzite, hematitic

4.07

42,485

293

0.2

5,887,000

40,600

14,195,500

97.9

A, very high

1 - low 3 - high

Sandstone

2.34

477

3

0.1

-

-

57,855

0.4

E, very low

Sandstone, argillaceous

2.80

15,225

105

0.05

2,146,000

14,800

4,509,500

31.1

C, medium

3 - high

Sandstone, calcareous

2.60

22,910

158

0.16

3,465,5000

23,900

8,018,500

55.3

B, high

2 - medium

Sandstone, ferriginous

2.60

19,140

132

0.22

2,189,500

15,100

5,553,500

38.3

B, high

3 - high

Sandstone, Navaho, cemented

2.15

12,601

87

-0.09

890,300

6,140

1,508,000

10.4

C, medium

3 - high

Sandstone, Navaho, cemented

2.31

13,094

90

-0.03

1,624,000

11,200

3,146,500

21.7

C, medium

3 - high

Schist, sericite

2.70

23,490

162

3,799,000

26,200

8,700,000

60.0

B, high

2 - medium

Shale

2.81

31,320

216

0.09

3,857,000

26,600

8,439,000

58.2

B, high

2 - medium

Shale, carbonaceous

2.30

16,240

112

0

949,750

6,550

2,015,500

13.9

B, high

3 - high

Shale, siliceous

2.80

33,495

231

0.12

4,422,500

30,500

9,874,500

68.1

A, very high

2 - medium

Siltstone

2.76

37,120

256

3,668,500

25,300

7,714,000

53.2

A, very high

2 - medium

Skarn, garnet-pyroxene

3.28

18,850

130

5,046,000

34,800

12,499,000

86.2

B, high

1 - low

Syenite

2.82

49,935

303

4,103,500

28,300

10,701,000

73.8

A, very high

2 - medium

Syenite, porphytric

2.70

62,930

434

4,393,500

30,300

10,295,000

71.0

A, very high

2 - medium

2.87

38,570

266

4,016,500

27,700

8,903,000

61.4

A, very high

2 - medium

Tactite, epidote

272

0.11

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Guides for best bit performance I. Exercise care in making-up and breaking-out the drill bit to avoid damaging the bit threads and drill steel. A. After the connection is broken, avoid down pressure on the bit breaker when unscrewing. Hoist the drill steel high enough for the bit to drop from the box connection into the bit breaker. B. Make sure the deck is clean and the bit breaker is properly mounted in its holder. C. Clean the threads on the new bit and on the drill steel, make sure the mating shoulders are clean and a quality “anti-galling” lubricant has been applied. D. Stab carefully - avoid excessive pressure on high angle thread flank. Re-level the machine if the drill stem box doesn’t align with bit pin. E. Always use low torque and slow RPM when making up connection. Mating shoulders should smoothly make up to 1/8” with low torque. II. When a new bit is installed, drill at reduced weight for a short break-in period. Use the 1/3 - 2/3 rules: • 1/3 of normal weight and RPM for 1/3 of the first hole • 2/3 normal weight and RPM for the next 1/3rd of the hole.

• Normal drilling parameters to finish the hole.

A. After the break-in period, bit cones should be checked to be sure that all are about the same temperature. One hot cone generally indicates that the air passage to that particular bearing has become obstruction. If one cone is hot the bit should be inspected before any damage occurs. B. Make sure that all assembly grease is blown out of all three cutters. When the air is turned on, air should blow out of the back of each cone. III. Provide adequate air to the bit to insure trouble free bearing performance and reduced abrasion wear on cones and shirttails. A. The compressed air serves two functions: • Air to the bearings, to cool and clean the assembly.



• Hole cleaning to remove cuttings from the blasthole. • To insure maximum bearing life, a 40 psi mini mum pressure drop across the bit is desirable.

Tricone bits

B. Hole cleaning is based on feet/minute of up hole annular velocity. • Air volume should produce a minimum of 5,000 linear feet per minute annular return velocity for removal of light cuttings and 7,000 feet per minute for heavy material. • Low up-hole velocity causes cuttings to fall back to bottom until they are reground small enough to be carried out of the hole. • An increase in torque, torque fluctuations, either hydraulic pressure or amp’s, or an increase in air pressure, are all indications that the hole is not being cleaned. C. Some indications that the hole is not being properly cleaned are: • Increase in torque indication through higher hydraulic pressure or higher amp meter reading. • Increase in air pressure. • Excess of cuttings in the bottom of the hole (more than one foot - after completion of hole and after making a cleaning pass). • Heavy wear and/or damage indications on shirttails. D. Some reasons for an increase in air pressure while drilling:

• Fast penetration, not cleaning the holes.

• Foreign material in the bit, coming from inside the air system, or cuttings coming in through the air nozzles or shirttails. • Air passages to the bearings becoming plugged with cuttings.



IV. Turn the air on before lowering the bit to collar the hole. Keep the air on until the bit is finished drilling and is out of the hole. Always rotate the bit when moving in or out of the hole. A. Make sure the cab gage pressure is at its normal reading and air is circulating through the bit before starting to drill. Inadequate air to the bearings is a principal cause of overheating and early bearing failure. B. Always rotate when coming out of the hole to: • Help clean cuttings from the hole. • Keep cuttings from entering the bearings around the back face of the cone.

Blasthole Drilling in Open Pit Mining 273

Rotary drilling TOOLS

Guides for best bit performance • Eliminate the possibility of clogging and jamming of the roller stabilizer rollers. (If used.)

C. Always rotate when going in the hole to:

• Decrease the possibility of damaging the bit or stabilizer on a ledge or other protrusion in the hole. D. Never use the hydraulic down pressure on the bit to aid in levelling the machine. V. Maintain as high a pressure drop across the bit as possible when in wet holes, or when water injection is used. A. The extra pressure drop helps to keep water and cuttings from entering the bearings. B. When adding extra drill steel in wet holes, always make three or four cleaning passes to get the bottom of the hole as clean as possible. C. Never remove any device that the manufacturer has installed from inside the bit. VI.

Regularly inspect the bit and feel the cones to be sure that all are about the same temperature. One hot cone generally indicates that the passages to that particular bearing have become obstructed.

A. When making this inspection rotate the cones and make sure the bearings are clean and not locked with cuttings. B. If the cones do not rotate freely, start the air compressor and blow the cuttings from the bearings, then repeat the inspection. C. Any time the cones cannot be freed, the bit should be taken off for inspection and cleaned. VII. Never allow the bit to drop while on the end of the drill steel, even for distance of a few inches - dropping the bit can cause cracking of the welds, and/or indentations in the bearing races. Results will be premature bearing failure. VIII. When a partially dull bit sits idle for a shift or longer, rotate the cones by hand to insure that they turn freely before drilling.

274

Tricone bits

A. If the bit sits idle for any length of time, in freezing conditions, and where water injection is used, water can freeze inside the bearings and air passages. The air temperature from compressor will normally melt the ice if enough time is allowed before starting to drill.



B. The drill steel and bit should be warm before the water injection is used. This will prevent the water from freezing to the cold surfaces. C. A partially dull bit should never be left down the hole when repairs require lowering the head assembly to the deck. This bit should be substituted by a dull bit to protect the drill steel threads. D. Procedures for cleaning a bit that has been taken off the drill and will be reused:

• Flush the bearings with water making sure the water is going though each bearing.



• Force air through each bearing.



• Oil bearings and submerge in non-detergent oil.

IX. Occasionally check the air pressure with the bit off to insure that there are no obstructions in the hole swivel or steel. A. A pressure reading with the bit off can be taken at each bit change and recorded on the drill report. A change from the prior reading will help determine if a new obstruction or new leak has developed. B. At each bit change any foreign material in the dull but should be noted or investigated. X. Properly maintain the drill steel and its threaded connections. A bent steel will often cause early failure. A. A bent drill steel will cause excess loading on one of two cones with resulting bearing failure on those cones. B. Wear patterns on one side of the drill steel and stabilizer are also indications of the problem. XI. Blasthole bits drill most economically when sufficient weight is applied to cause spalling of the formation.

Blasthole Drilling in Open Pit Mining

Rotary drilling TOOLS

Guides for best bit performance A. When spalling occurs the cuttings are large and the penetration rate is improved. B. If a sufficient amount of weight is not applied, the cutting structure will tend to skid along the bottom causing early wear, thus reducing penetration rate and shortening bit life. C. If too much weight is used for the formation, the cutting structure can be buried to full depth, trapping cuttings beneath the bit. This will cause erosion of the cone metal, prevent the formation from chipping, and reduce the penetration rate. If cuttings are forced into the cone, bearings can lock up. Heavy weights will also reduce hours of bearing life.

Tricone bits

XII. Selecting correct rotary speed is usually a matter of trial and error, depending upon the formation being drilled. A. Slower RPM’s will reduce the penetration rates and generally increase bit life. B. Faster RPM’s increase the penetration rates and if excessive RPM’s are used, it tends to shorten bit life. C. Increased penetration rate is usually the result of better spalling of large cuttings.

Blasthole Drilling in Open Pit Mining 275

DTH HAMMER SPECIFICATIONS

Industry overview The quarry and mining operations typically have high equipment utilization, drilling 60%, even up to 80%, of the working day. Companies drilling small to medium blast holes between 85 to 152 mm (3 3⁄8" to 6") find that performance and service life are critical. For those operations drilling large blast holes (greater than 152 mm), performance, reliability, fuel efficiency, servicelife and support are critical. This is often the ideal application for considering premium DTH (Down-TheHole) hammers with faster drill rates resulting in less time in the hole. This not only reduces labor costs, but lowers wear and tear on expensive drills. For surface mining, pre-splitting is often carried out to improve slope stability. The pre-splitting holes are often 115   -140 mm (4 ½" - 5 ½") and can be made before the drilling of the production holes. Selecting the right hammer The optimum range of hole size for blast hole drilling with DTH is 90 mm to 254 mm (3 ½"–10"). Smaller blast holes are generally drilled using tophammer, and larger holes generally use rotary machines. In other applications, like foundation drilling, DTH hammers can be used with single bit in hole sizes up to 914 mm (36"). With multiple hammer units CD (Cluster Drills) drill holes up to 70" or 1778 mm as standard. Larger cluster drills can be delivered as per customer request. As a rule of thumb, the smallest hole diameter a DTH hammer can drill is its nominal size. A 4 inch hammer 276

will drill a 4 inch (102 mm) hole. The limiting factor is the outside diameter of the hammer, because, as hole diameter reduces, airflow is restricted. Maximum hole size for production drilling is the nominal hammer size plus 1 inch, so for a 4 inch hammer the maximum hole size is 5 inch (127-130 mm). Choosing the right hammer is largely determined by hole size and type of rock formation. Ideally, the size of the hammer should match the required hole dimension as closely as possible, leaving just enough space for cuttings to evacuate the hole. Secoroc hammers are purpose-matched for all rock types and applications. Where high performance is the main criterion, Secoroc COP Gold hammers are recommended in blast hole drilling and Secoroc QLX hammers in deep hole drilling app­lications. The QLX hammer has proven superior performance and adaptability to different air requirements thanks to the Air Select System. Where proven technology is required, the Secoroc COP and QL hammers are known for their reliability and longevity. They are practically bullet proof, making them useful for production drilling in quarries, shallow water well drilling, and underground blasthole drilling. QM is similar to Standard, but with heavy duty chuck and wear sleeve, and a back head fitted with tungsten carbide buttons for wear protection in harsh and abrasive conditions. These also protect the back head from excessive wear when rotating out of the hole through broken rock. Blasthole Drilling in Open Pit Mining

DTH HAMMER SPECIFICATIONS

Economy kits In hard and abrasive drilling condition the external parts of DTH hammer is wearing out before the internal parts reaches their fatigue limits. In these conditions the E-kit can serve as a tool to reduce the total drilling cost. With the E-kit the hammer can be rebuilt and the internal part re-used for another run. The cost saving can be substantial as the cost for an E-kit is only 50% of a new hammer. An E-kit contains all the needed parts for a rebuild and will ease the logistic constrains as all needed parts can be ordered under one product number.

A rule of thumb for use of E-kits Rock formation

Hammer life Action

Highly abrasive < 5000 m

Use E-kit to rebuild the hammer 1-2 times

Medium abrasive

5-10 000 m

Consider E-kit to rebuild the hammer 1 time

None abrasive

>10 000 m

Rebuilding not recommended, risk that internal parts might fail before E-kit worn out

Breakout bench

Reverse circulation

The threaded connections of the driver chuck and back head may become very tightly tensioned during drilling. It is convenient to break the hammer threads on the rig, but if the threads cannot be loosened or tend to get stuck, a breakout bench is the solution.

Atlas Copco Secoroc's reverse circulation hammers are specifically designed for all kind of exploration drilling (deep hole and pit grade control applications).

This handy but powerful breakout bench can easily be placed in a workshop or container and it breaks DTH hammers between 3" and 8". Select right breakout bench depending on voltage and power source.

Whether you are exploring potential sites or working an existing mine, the Secoroc RC hammer will assure of high performance, exceptional reliability and dependable support.

Blasthole Drilling in Open Pit Mining 277

DTH HAMMER SPECIFICATIONS

Technical specifications Model

COP 44 Gold

COP 54 Gold

COP 54 Gold QM

COP 64 Gold

COP 64 Gold QM

QLX 35

Bit shank style

TD 40

QL 50

QL 50

QL 60

QL 60

DHD 3.5

Product code

9704-03-34

9705-05-34

9705-05-36

9706-05-34

9706-05-36

9703-03-68-00

89001469

89001243

89001255

89000959

89000960

Product number General specifications

English

Connection thread

API 2 3/8" Reg Pin

Outside diameter (in/mm)

Metric

English

Metric

API 3 1/2" Reg Pin

English

Metric

API 3 1/2" Reg Pin

English

Metric

API 3 1/2" Reg Pin

English

89001572

Metric

API 3 1/2" Reg Pin

English

Metric

API 2 3/8" Reg Pin

3.9

100

4.7

120

4.9

126

5.6

142

5.8

146

3.1

79

Length w/o bit shoulder to shoulder (in/mm)

40.8

1 037.5

51.5

1 194.2

51.5

1 194.2

49.5

1 258

49.5

1 258

31.4

799

Weight w/o bit (lb/kg)

89.3

40.5

145.0

65.7

167.0

75.6

211.0

96.0

240.0

109.0

65.0

29.5

Backhead across flats (in/mm)

2.6

65

3.7

95

3.7

95

4

102

4

102

2.5

63.5

Min bit size (in/mm)

4.3

110

5.3

134

5.5

140

6.1

156

6.5

7

3.5

90

Max bit size (in/mm)

5.1

130

6

152

6

152

7

178

7

178

4.1

105

Bore (in/mm)

3.2

82

3.9

100

3.9

100

4.7

120

4.7

120

2.52

64

17.4

7.9

33.0

15.0

33.0

15.0

45.0

20.5

45.0

20.5

12.0

5.5

Stroke (in/mm)

4.5

115

4.5

115

4.5

115

4.5

115

4.5

115

4

101.6

Max pressure differential (psi/bar)

508

35

435

30

435

30

435

30

435

30

435

30

Make-up torque (ft-lbf/Nm)

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

3 000

4 067

Piston weight (lb/kg)

Air consumption / Bpm *Estimated values 400-508 psi (27.6-35 bar) 150 psi / 10.3 bar (scfm / l/s) 150 psi (bpm) 200 psi / 13.8 bar (scfm / l/s) 200 psi (bpm) 250 psi / 17.2 bar (scfm / l/s) 250 psi (bpm) 300 psi / 20.7 bar (scfm / l/s) 300 psi (bpm) 350 psi / 24.1 bar (scfm / l/s) 350 psi (bpm) 400 psi / 27.6 bar (scfm / l/s)* 400 psi (bpm) 435 psi / 30 bar (scfm / l/s)* 435 psi (bpm)* 508 psi / 35 bar (scfm / l/s)* 508 psi (bpm)*

215

101

311

147

311

147

334

158

334

158

219

103

1 540

1 540

1 389

1 389

1 389

1 389

1 303

1 303

1 303

1 303

1 509

1 509

321

151

425

201

425

201

509

240

509

240

288

136

1 677

1 677

1 497

1 497

1 497

1 497

1 447

1 447

1 447

1 447

1 699

1 699

427

201

557

263

557

263

688

325

688

325

348

164

1 842

1 842

1 614

1 614

1 614

1 614

1 548

1 548

1 548

1 548

1 858

1 858

533

251

719

339

719

339

862

407

862

407

400

189

1 973

1 973

1 750

1 750

1 750

1 750

1 691

1 691

1 691

1 691

1 987

1 987

639

302

891

421

891

421

1 072

506

1 072

506

444

210

2 095

2 095

1 886

1 886

1 886

1 886

1 817

1 817

1 817

1 817

2 087

2 087

745

352

1 009

476

1 009

476

1 326

626

1 326

626

645

275

2 218

2 218

2 022

2 022

2 022

2 022

1 962

1 962

1 962

1 962

2 293

2 293

819

387

1 081

510

1 081

510

1 504

710

1 504

710

847

340

2 303

2 303

2 118

2 118

2 118

2 118

2 063

2 063

2 063

2 063

2 500

2 500

6-19

1 300-4 120

6-19

1 600-4 400

7-20

1 600-4 400

7-20

1 500-2 000

957

452

2 462

2 462

Operational specifications Feed Force (lb / kN) Rotation (rpm)

278

1 100-3 300 25-100

5-15

1 300-4 120 20-70

20-70

15-60

15-60

9-7

70-100

Blasthole Drilling in Open Pit Mining

DTH HAMMER SPECIFICATIONS

Some nice picture of Quantum leap hammers to put here

Technical specifications Model

QLX 50

QLX 55

QLX 60

QLX 65

RC 50

Bit shank style

QL 50

QL 50

QL 60

QL 60

RC 50

Product code

9705-05-68-00

9705-05-68-14

9706-05-68-00

9706-05-68-14

9705-52-67-00

89010092

89010093

52352465

52352473

Product number General specifications Connection thread Outside diameter (in/mm)

English

Metric

API 3 1/2" Reg Pin

English

Metric

API 3 1/2" Reg Pin

English

Metric

API 3 1/2" Reg Pin

English

52292273

Metric

API 3 1/2" Reg Pin

English

Metric

4 1/2" Remet BOX

4.8

121.9

5.08

129.0

5.6

142.2

5.88

149.4

5.13

130

Length w/o bit shoulder to shoulder (in/mm)

41.76

1 060.7

41.76

1 060.7

41.67

1 090.7

41.67

190.7

45.4

1 152

Weight w/o bit (lb/kg)

153.0

69.5

178.0

80.9

205.0

93.2

235.0

106.8

72

158

Backhead across flats (in/mm)

3.7/4

95/102

3.7/4

95/102

4

101.6

4

102.6

4

102

Min bit size (in/mm)

5.25

133

5.5

140

6.13

155.5

6.5

165.1

5 3⁄8

136

Max bit size (in/mm)

6

152

6

152

8.5

215.9

8.5

215.9

6 ½*

165*

Bore (in/mm)

3.95

100.25

3.95

100.25

4.75

120.65

4.75

120.7

4.48

113.7

Piston weight (lb/kg)

33.0

15.0

33.0

15.0

47.0

21.4

47.0

21.4

38

17

Stroke (in/mm)

3.75

95.3

3.75

95.3

3.75

95.3

3.75

95.3

2.5

64

Max pressure differential (psi/bar)

500

34.5

500

34.5

500

34.5

500

34.5

500

35

5 000

6 770

5 000

6 770

6 000

8 100

6 000

8 100

5 000

6 800

Make-up torque (ft-lbf/Nm)

* For setting casing

Air consumption / Bpm *Estimated values 400-508 psi (27.6-35 bar) 150 psi / 10.3 bar (scfm / l/s) 150 psi (bpm) 200 psi / 13.8 bar (scfm / l/s) 200 psi (bpm) 250 psi / 17.2 bar (scfm / l/s) 250 psi (bpm) 300 psi / 20.7 bar (scfm / l/s) 300 psi (bpm) 350 psi / 24.1 bar (scfm / l/s) 350 psi (bpm)

257

121

257

121

360

170

360

170

N/A

N/A

1 426

1 426

1 426

1 426

1 500

1 500

1 500

1 500

N/A

N/A

374

177

374

177

502

237

502

237

466

220

1 547

1 547

1 547

1 547

1 616

1 616

1 616

1 616

1 744

1 744

508

240

508

240

655

309

655

309

N/A

N/A

1 668

1 668

1 668

1 668

1 732

1 732

1 732

1 732

N/A

N/A

657

310

657

310

818

386

818

386

648

306

1 788

1 788

1 788

1 788

1 847

1 847

1 847

1 847

2 026

2 026

822

388

822

388

993

469

993

469

792

374

1 909

1 909

1 909

1 909

1 963

1 963

1 963

1 963

2 238

2 238

400 psi / 27.6 bar (scfm / l/s)* 400 psi (bpm)

951

449

2 340

2 340

435 psi / 30 bar (scfm / l/s)* 435 psi (bpm)* 508 psi / 35 bar (scfm / l/s)* 508 psi (bpm)* Operational specifications Feed Force (lb / kN) Rotation (rpm)

1 500-2 000 50-80

9-7

1 500-2 000 50-80

9-7

2 000-3 000 30-60

9-13.3

2 000-3 000

9-13.3

30-60

Blasthole Drilling in Open Pit Mining 279

secoroc grinding

The right tools to get you back on the cutting edge

Every regrinding operation requires its own special tool. The wrong one can easily damage your bits. With Secoroc grinding equipment – complemented by a global service organization – you needn’t worry. Your bits will soon be as good as new.

A machine for every occasion Button bits

Grinding machine Secoroc BQ3



Secoroc Jazz



Secoroc Manual B



Secoroc HG



DTH/COPROD bits

Reaming bits

Integrals

 

 



Secoroc BQ3-DTH



Secoroc Manual B-DTH*





Secoroc Swing



Secoroc Senior



 Recommended

280

Can be used

* Can be used for ODEX pilot bits and reaming bits.

A useful tip: use a Secoroc grinding template, and you’ll see when it’s time for a regrind.

Blasthole Drilling in Open Pit Mining

secoroc grinding

Grinding Secoroc BQ3

Secoroc BQ3-DTH

Secoroc Jazz

Semi-automatic grinding machine for button bits.

Semi-automatic grinding machine for DTH- and COPROD bits.

Rig-mounted, semi-automatic grinding machine for tapered, threaded, DTH- and COPROD bits.

Electrical specifications 400 V 3-phase 50 Hz 230 V 3-phase 50 Hz 400 V 3-phase 60 Hz 230 V 3-phase 60 Hz 440 V 3-phase 50 Hz

Electrical specifications 400 V 3-phase 50 Hz 230 V 3-phase 50 Hz 400 V 3-phase 60 Hz 230 V 3-phase 60 Hz 440 V 3-phase 50 Hz

Secoroc Jazz, standard incl. main bit holder for threaded bits

Grinding capacity Maximum height of drill bit Maximum diameter of drill bit Maximum bit skirt diameter Minimum distance between buttons

Prod No. 87004800 87004801 87004803 87004805 87004806 200 mm (7 7⁄8") 127 mm (5") 120 mm (4.75") 3.5 mm (9⁄64")

Technical data Air pressure, max. 7 bar (101.5 psi) Air pressure, min. 5.5 bar (80 psi) Air consumption 40 l/min Capacity of cooling-fluid tank 22 l Output, spindle motor 1.50 kW Output, driving plate motor 0.37 kW Output, coolant pump motor 0.44 kW Speed, spindle 14 900 r/min Speed, table (50 Hz) 62 r/min Speed, table (60 Hz) 74 r/min Voltage working lighting 24 V Weight, excluding packaging 222 kg (490 Ib) Transport dimension L 1 730 x W 1 030 x H 1 160 mm (68.11" x 40.55" x 43.94") Accessories included in delivery Allen key, 4 mm (1 piece) Centring cup, 11 mm Centring device (1 piece) Coolant concentrate, 0.5 l Extractor Filter key Grinding wheel, uncoated for centering Protective goggles Operator’s instructions and spare parts list Note: Secoroc BQ3 must be completed with grinding wheels, centring cups, bitholders (indicate button size and thread dimension) and indexing templates.

Blasthole Drilling in Open Pit Mining

Prod. No. 87004900 87004901 87004903 87004905 87004906

Grinding capacity Maximum height of drill bit 650 mm (2'1 5⁄8") Maximum diameter of drill bit 178 mm (7") Minimum distance between buttons 3.5 mm (9⁄64") Technical data Air pressure, max. 7 bar (101.5 psi) Air pressure, min. 5.5 bar (80 psi) Air consumption 40 l/min Capacity of cooling-fluid tank 22 l Output, spindle motor 3.00 kW Output, table drive motor 0.25 kW Output, coolant pump motor 0.44 kW Speed, spindle 14 900 r/min Speed, table (50 Hz) 22 r/min Speed, table (60 Hz) 26 r/min Voltage working lighting 24 V Weight, excluding packaging 345 kg (760 lb) Transport dimension L 1 200 x W 1 200x H 1 700 mm (47.24" x 47.24" x 66.93") Accessories included in delivery Allen key, 4mm (1 piece) Coolant concentrate, 0.5 l Extractor Protective goggles Operator’s instructions and spare parts list Optional accessories - Auxiliary set for grinding threaded bits (excl. bitholder and templates)

Prod. No. 87003939

NOTE: Secoroc BQ3-DTH must be completed with grinding wheels, centring cups and bitholders (indicate button size, bit diameter and type of hammer).

Prod. No. 87004100

Secoroc Jazz, DTH Prod. No. incl. main bit holder for DTH/COPROD bits 87004300 Grinding capacity Maximum distance between bit holder and grinding wheel 250 mm (9 7⁄8") Maximum diameter of drill bit 254 mm (10") Minimum diameter of drill bit 35 mm (1 3⁄8") Minimum distance between buttons 3.5 mm (9⁄64") Technical data Air pressure, max. 7 bar (101.5 psi) Air pressure, min. 6 bar (87 psi) Air consumption 25 l/s Coolant container 3l Output, spindle motor 1.00 kW Speed, spindle 15 000 r/min Voltage 24 V Weight, excluding packaging 90 kg (198 lb) Transport dimension L 800 x W 500 x H 700 mm



(2'7 ½" x 1'7 5⁄8" x 2'3 ½")

Accessories included in delivery Box wrench, 11 mm Box wrench, 16 mm Grinding gauge Protective goggles Operator's instructions and spare parts list Optional accessories - Anti-freeze kit - Main bit holder for DTH/ COPROD bits - Main bit holder for threaded bits - Mounting bracket for Atlas Copco drill rig - with cabin - without cabin - 3-leg stand - Centring tool

Prod. No. 87004315 87004268 87004214 87004628 87004456 87004450 87004465

NOTE: Secoroc Jazz must be completed with grinding wheels, centring cups, bitholders and indexing templates.

281

secoroc grinding

Grinding Secoroc Manual B

Secoroc Manual B-DTH

Secoroc HG

Hand-held portable grinding machine for button bits.

Hand-held portable grinding machine for DTH- and COPROD bits.

Hand-held grinding machine for button bits.

Secoroc Manual B

Secoroc Manual B-DTH

Secoroc HG

Grinding capacity Maximum diameter of bit skirt Threaded bits, maximum diameter Retrac, maximum diameter Tube drilling, maximum diameter * Large clamping device necessary

Prod. No. 87001890 90 mm (3 9⁄16") 127 mm (5") *127 mm (5") *152 mm (6")

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption 15 l/s Coolant container 10 l Idling speed of hand-held grinder 30 000 r/min Speed of bit rotation 0-45 r/min Weight, excluding packaging 55 kg (121.3 Ib) Weight, including packaging 90 kg (198.4 Ib) Transport dimension L 1 200 x W 800 x H 850 mm (3'11 2⁄10" x 2'7 5⁄10" x 2'9 5⁄10") Accessories included in delivery Allen key, 4 mm Centring fingers (4 pcs) Grinding templates, spherical and ballistic Hand-held grinder, 30 000 r/min Open end spanner, 14 mm (2 pcs) Protective goggles Operator’s instructions and spare parts list Optional accessories - Vibration absorbing sleeve to fit the hand-held grinder - Set of 5 centring fingers

Prod. No. 87001931 87001935

NOTE: Secoroc Manual B must be completed with grinding wheels and bitholders.

282

Grinding capacity Maximum height of drill bit Maximum diameter of drill bit Maximum diameter of bit shank

Prod. No. 87002300 506 mm (1'7 7⁄8") 203 mm (8") 170 mm (6 ¾")

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption 15 l/s Coolant container 10 l Idling speed of hand-held grinder 30 000 r/min Speed of bit rotation 0-45 r/min Weight, excluding packaging 110 kg (253 lb) Weight, including packaging 148 kg (326 lb) Transport dimension L 1 200 x W 800 x H 940 mm (3'11 2⁄10"x 2'7 5⁄10" x 3'1 0⁄10") Accessories included in delivery Allen key, 5 mm Allen key, 6 mm Centring fingers (4 pcs) Grinding templates, spherical and ballistic Hand-held grinder (spherical, 30 000 r/min) Open end spanner, 14 mm (2 pcs) Protective goggles Operator’s instructions and spare parts list Optional accessories Prod. No. - Centring fingers (set of 5 pcs), 30 000 r/min 87001935 - Clamping device for threaded bits 87002401 NOTE: Secoroc Manual B-DTH must be completed with grinding wheels and bitholders.

Grinding capacity Button size

Prod. No. 87002435 7-20 mm (9⁄32"- 25⁄32")

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption, unloaded 50 l/s Air consumption, loaded (at 6 bar, 86 psi) 42 l/s Hose dimension, air 12.5 mm (½") Hose dimension, water 6.3 mm (¼") Idling speed 17 000 r/min Water flushing pressure, max. 4.5 bar (65.3 psi) Weight, excluding hoses 2.8 kg (6.2 Ib) Accessories included in delivery Adjustable angle connector Allen key, 2 mm Allen key, 3 mm Allen key, 5 mm Claw coupling (6.3 mm) Grease gun Grinding templates, spherical and ballistic Hose (PVC 03) Hose (PVC 6; L = 0.1 m) Hose clamp (7–8.5 mm) Hose clamp (11–13 mm) Hose clamp (26–38 mm) Nipple Pipe (L = 0.3 m) Seal kit Seat Support ring Operator’s instructions and spare parts list Optional accessories - Lubricator - Reconditioning tool for grinding cups

Prod. No. 87002750 87002810

Blasthole Drilling in Open Pit Mining

secoroc grinding

Grinding Secoroc Swing

Secoroc Senior

Grinding machine for integrals.

Grinding machine for integrals.

Secoroc Swing

Prod. No. 87002482

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption (at 6 bar, 86 psi) 25 l/s Cutting-edge angle 110° Cutting-edge radius 80 mm (3 5⁄32") Gauge grinding arrangement included Hose connections: - Air 12.5 mm (½") - Water 6.3 mm (¼") Idling speed 4 080 r/min Power output 1,10 kW Size of grinding wheel - D x T x H 125 x 63 x 32 mm (47/8" x 215/32" x 1¼") - DI x TI 80 x 50 mm (3 5/32" x 2") Spindle diameter 16 mm (5/8") Weight incl. grinding wheel and 1.5 m water hose 27.5 kg (61 lb) Accessories included in delivery Grinding template Grinding wheel, soft Pin wrench Protective goggles Operator’s instructions and spare parts list Optional accessories - Grinding wheel, hard - Grinding wheel, soft - Chuck bushing wear gauge H19 (0,75") H22 (0,85") H25 (1")

Prod. No. 87002589 87002811 90002667 90002668 90002669

Blasthole Drilling in Open Pit Mining

Electrical specifications 220 V 3-phase 50 Hz 220 V 3-phase 60 Hz 380 V 3-phase 50 Hz 380 V 3-phase 60 Hz 415 V 3-phase 50 HZ 415 V 3-phase 60 Hz 440 V 3-phase 60 Hz

Prod. No. 87002485 87002493 87135402 87002494 87002488 87002495 87002496

Technical data Air pressure, max. 7 bar (101.5 psi) Cutting-edge angle, adjustable 90  -130° Grinding wheel -DxTxH 200 x 102 x 32 mm (7 7⁄8" x 4" x 1 ¼) - DI x TI 150 x 80 mm (5 7⁄8" x 3 5⁄32") - Cutting-edge radius, adjustable 80-130 mm (3  5⁄32"- 5 1⁄8") Idling speed, electric 50 Hz 2 840 r/min Idling speed, electric 60 Hz 1 690 r/min Output 3-phase 1.50 kW Rod hex. max. 25 mm (1") Weight excluding packaging 105 kg (232 lb) Weight including packaging 120 kg (265 lb) Transport dimension L 800 x W 600 x H 650 mm (2'7 ½" x 1'11 5⁄8" x 2'1 5⁄8")

Secoroc Swing.

Accessories included in delivery Grease gun Grinding template Grinding wheel, hard Protective goggles Socket wrench Wrench Operator’s instructions and spare parts list Optional accessories - Grinding wheel, hard - Grinding wheel, soft - Spacer plate for H19 integral - Chuck bushing wear guage H19 (0.75") H22 (0.85") H25 (1")

Prod. No. 87002591 87002813 87000519 90002667 90002668 90002669

Secoroc integral equipment.

283

secoroc grinding

Profiled diamond grinding wheels for button bits Secoroc BQ3/BQ3-DTH Secoroc Jazz/Jazz-DTH Secoroc Manual B/Manual B-DTH

Grinding wheel for spherical buttons

Dimension, mm

Product No.

Grinding wheel for ballistic buttons

Product code

Spherical

Grinding wheel for full-ballistic buttons

Dimension, mm

Product No.

Product code

Dimension, mm

Product No.

Product code

19

87003966

9500-3966

18

87003965

9500-3965

19

87003967

9500-3967

7

87001028

9500-1028

Ballistic

8

87001026

9500-1026

7

87003407

9500-3407

Full-ballistic

9

87001389

9500-1389

8

87003408

9500-3408

7

87004720

9500-4720

10

87001023

9500-1023

9

87003409

9500-3409

8

87004721

9500-4721

11

87003406

9500-3406

10

87003410

9500-3410

9

87004722

9500-4722

12

87001024

9500-1024

11

87003411

9500-3411

10

87004723

9500-4723

13

87001339

9500-1339

12

87003412

9500-3412

10,95

87004724

9500-4724

14

87001025

9500-1025

13

87003413

9500-3413

12,7

87004725

9500-4725

14,5

87004708

9500-4707

14

87003414

9500-3414

14,5

87004726

9500-4726

15

87001384

9500-1384

14,5

87004717

9500-4717

15,83

87004727

9500-4727

16

87001027

9500-1027

15

87003415

9500-3415

18

87003964

9500-3964

16

87003416

9500-3416

Centering cups*

Grinding wheels for steel grinding Dimension

Product No.

Product code

Button size

Product No.

Product code

Button size

Product No.

Product code

10–14 mm

87001530

9500-1530

7,0 mm

87001040

9500-1040

13,0 mm

87001385

9500-1385

Spacer for 10 mm button

87001631

9500-1631

8,0 mm

87000842

9500-0842

14,0 mm

87001043

9500-1043

Spacer for 11 mm button

87001632

9500-1632

9,0 mm

87001047

9500-1047

14,5 mm

87001443

9500-1443

Spacer for 12 mm button

87001633

9500-1633

10,0 mm

87001041

9500-1041

15,0 mm

87001386

9500-1386

Spacer for 13 mm button

87001634

9500-1634

11,0 mm

87000840

9500-0840

16,0 mm

87001387

9500-1387

Spacer for 14 mm button

87001635

9500-1635

12,0 mm

87001042

9500-1042

18,0 mm

87003943

9500-3943

12,7 mm

87000839

9500-0839

19,0 mm

87003944

9500-3944

* NOT needed for Manual B/Manual B-DTH

284

Blasthole Drilling in Open Pit Mining

secoroc grinding

Bitholders for button bits Secoroc BQ3/Jazz Secoroc BQ3-DTH/Jazz-DTH Secoroc Manual B-DTH Type

A

Secoroc BQ3/Jazz – Threaded bits* R25 R28 SR28 R32 SR32 SR35 TC35 R38 T38 SR38 SR38 retrac, guide TC42 T45 TC45 T51 and retrac T60

Secoroc Manual B/Manual B-DTH

Product No.

Product code

87003475 87003476 87003960 87003477 87003962 87003956 87005007 87005005 87005006 87003978 87004081 87004641 87003479 87004569 87003521 87004562

9500-3475 9500-3476 9500-3960 9500-3477 9500-3962 9500-3956 9500-4685 9500-4686 9500-4687 9500-3978 9500-4081 9500-4641 9500-3479 9500-4569 9500-3521 9500-4562

Product No.

Product code

R25

87000792

9500-0792

R28

87000793

9500-0793

SR28

87003961

9500-3961

R32

87000794

9500-0794

R32

87001848

9500-1848

SR32

87003963

9500-3963

R35

87003360

9500-3360

SR35

87003957

9500-3957

R38/T38

87000795

9500-0795

SR38

87003979

9500-3979

T45

87000796

9500-0796

T51

87000802

9500-0802

7° taper

87001044

9500-1044

12° taper

87001045

9500-1045

ST58

87001726

9500-1726

ST68

87001573

9500-1573

64, 76, 89 mm

87000798

9500-0798

89, 102, 127 mm

87000799

9500-0799

Type Secoroc Manual B – Threaded bits

Secoroc BQ3/Jazz – Tube bits* ST58 ST68

87003522 87003523

9500-3522 9500-3523

Secoroc BQ3/Jazz – Tapered bits* 7° taper 12° taper

87003524 87003525

9500-3524 9500-3525

Secoroc BQ3/Jazz – Reaming bits* 64, 76 and 89 mm 89,102 and 127 mm

87003526 87003527

9500-3526 9500-3527

Secoroc BQ3/Jazz – Guide bits* R32 SR35

87003992 87004056

9500-3992 9500-4056

C

Secoroc Manual B – Tapered bits

Secoroc Manual B – Tube bits

Secoroc Manual B – Reaming bits

Secoroc BQ3-DTH/Jazz-DTH/Manual B-DTH – DTH and Coprod bits

B

COP 32

87002420

9500-2420

COP 34

87003691

9500-3691

DHD 3.5

87004514

9500-4514

DHD 340, TD 35

87002391

9500-2391

DHD 350

87002390

9500-2390

DHD 360

87002389

9500-2389

DHD 380

87004523

9500-4523

TD 40

87004604

9500-4604

QL 40, TD 50

87004515

9500-4515

QL 50, TD 60

87004033

9500-4033

QL 60, TD 80

87004002

9500-4002

QL 80

87004516

9500-4516

TD 90

87004517

9500-4517

RC 50

87004605

9500-4605

COPROD 76

87004414

9500-4414

COPROD 89

87003155

9500-3155

COPROD 102

87004415

9500-4415

COPROD 127

87002396

9500-2396

* To be able to grind tophammer bits on Secoroc BQ3-DTH, the clamping device with Product No. 87003939 / Product code 9500-3939 must be used.

Blasthole Drilling in Open Pit Mining

Bitholder type A

Bitholder type C

Bitholder type B

285

secoroc grinding

Diamond grinding cups Secoroc HG

For sperical buttons

For ballistic buttons

For steel removal around buttons

286

Dimension, mm

Product No.

Product code

7,0

87002566

9500-2566

8,0

87002567

9500-2567

9,0

87002568

9500-2568

10,0

87002569

9500-2569

11,0

87002570

9500-2570

12,0

87002571

9500-2571

13,0

87002572

9500-2572

14,0

87002573

9500-2573

15,0

87002574

9500-2574

16,0

87002575

9500-2575

18,0

87002576

9500-2576

19,0

87004558

9500-4558

20,0

87002577

9500-2577

7,0

87002579

9500-2579

8,0

87002580

9500-2580

9,0

87002581

9500-2581

10,0

87002582

9500-2582

11,0

87002583

9500-2583

12,0

87002584

9500-2584

13,0

87002585

9500-2585

14,0

87002586

9500-2586

15,0

87002587

9500-2587

16,0

87002588

9500-2588

7–8

87002700

9500-2700

9–10

87002701

9500-2701

11–12

87002702

9500-2702

13–14

87002703

9500-2703

15–16

87002704

9500-2704

17–18

87002840

9500-2840

19–20

87002841

9500-2841

Blasthole Drilling in Open Pit Mining

secoroc grinding

Ceramic grinding wheelss Cross-type bits, X-type bits and chisel bits Grinding machine

Bit size, mm

Grind Matic X Sandvik RG 300 Sandvik RG 320 Sandvik RG 340 Sandvik RG 360

Bit angle

Wheel angle

Dimension (D×T×H), mm

Dimension (DI×TI), mm

Product No.

Product code

35

90°

132°

300 x 23 x 32



87002594

9555

38–41

90°

132°

300 x 26 x 32



87002595

9556 9558

45

90°

132°

300 x 29 x 32



87002597

48–51

90°

132°

300 x 32 x 32



87002616

9577

76

90°

132°

300 x 52 x 32



87002603

9564

76

75°

126°

300 x 42 x 32



87002608

9569

76

105°

139°

300 x 58 x 32



87002609

9570

Secoroc Swing Sandvik RG 100

Secoroc Senior Grind Matic Junior





125 x 63 x 32

80 x 50, hard

87002589

9550





125 x 63 x 32

80 x 50, soft

87002811

9500-2811





125 x 63 x 32

80 x 50, hard endurance

87004700

9500-4700





125 x 63 x 32

80 x 50, soft endurance

87004701

9500-4701





200 x 102 x 32

150 x 80, hard

87002591

9552





200 x 102 x 32

150 x 80, soft

87002813

9500-2813





150 x 83 x 32

100 x 64, hard

87002590

9551





150 x 83 x 32

100 x 64, soft

87002512

9500-2812

Grinding templates Integral rods and bits 10 10 15

8

3/4" 1/2" 1/4"

5 10 15

1/4" 1/2" 3/4"

Min. 0,5

3/4"

Grinding template

1"

,5

1/2"

For integral rods

1 1/2"

Regrind when flat is 173 of button dia.

14

1/4"

7

5

3/32"

1/8" 3 mm

0

2,4 mm

r= 80 mm 3,5/32"

,95

10

9

10

20

12,7

30

Skivvinkel Wheel

D

110°

110° 40

D/3

For button bits

For cross-type bits

Dimension, mm

Product No.

Product code



90002610

9101

Button bits, spherical

7 - 14,5

90002944

9104

Button bits, ballistic

7 - 14,5

90503414

9105

Button bits, spherical

10,95 - 19,1

90510753

9129

Button bits, ballistic

10,95 - 19,1

90510758

9130



90002611

9102

Integral rods

Cross-type bits

Blasthole Drilling in Open Pit Mining

287

DrillCare

Parts and Services Wherever you are in the world, as an Atlas Copco customer your service experience will always be the same. It’s all about our commitment, our service promise, our capability and our quality. Furthermore, we aim to increase your productivity. This is the difference that is Atlas Copco Parts and Services. It’s not just about our promises, it’s about delivery.

Extended warranty Peace of mind for three years with no small print. Let us protect your investment. Features Benefits • Three years, unlimited operating hours • Focus on your production • Follow Atlas Copco maintenance schedule • Preventive maintenance • Atlas Copco genuine parts and selected oils and lubricants • Meet warranty conditions • Planned audits • Assures rig reliability

Service agreements Best-in-class maintenance to ensure reliability and highest availability of your drilling equipment. Features Benefits • Total maintenance • Minimize unplanned repairs • Preventive maintenance • Lowest operating cost • Fixed-price repair • Extended warranty period • Parts-only plans • Genuine Atlas Copco parts and selected lubricants

Preventive and corrective maintenance kits Atlas Copco genuine parts are manufactured to the same exacting quality standards as your drill rig. Features Benefits • Guaranteed performance • Warranted between scheduled services • Quality inspected and tested • Ensured reliability and highest availability • Available through our state-of-the-art distribution system • Quick, accurate order fulfillment

Atlas Copco Fluids Atlas Copco Fluids are produced to the exacting specifications required to meet the demands of your drilling application. Features Benefits • Designed for the toughest environment • Protect your investment • Performance tested • Optimize service life • Ensure extended warranty • Save money, minimize breakdowns

288

Blasthole Drilling in Open Pit Mining

DrillCare

Fluid Management Safer, cleaner reliability. Features Benefits • Hydraulic hose first aid kit • Limit downtime • Hydraulic filter cart • Maintain clean, efficient systems • Atlas Copco premium air hose • Safety and reliability • International expertise • Superior productivity

Hydraulic hose first aid kit Each kit provides an immediate replacement for every hydraulic hose on your drill rig. Features Benefits • Drill rig specific hoses and adaptors • Fastest possible fix • Complete instructions and accessories • First time fix at the jobsite • Environmenatally friendly • Spillage control • Wheel or truck mountable • Highly mobile

Diesel fuel filter cart A portable fuel cleaning system designed to protect your investment. Features Benefits • Controls particulate ingression • Maximize usable life of engine components • Prevents water contamination • Minimize downtime • Easy spin-on replacement elements • Lower maintenance cost

Hydraulic filter cart A superior contamination control device designed with maximum protection in mind. Features Benefits • Multi-stage filtration • Prevents secondary failures • Highest quality components • Safety and reliability • Flexible configurations • Matched to your specific needs • Easy spin-on replacement elements • Save time, save money

Blasthole Drilling in Open Pit Mining 289

Service

Our presence marks The Difference Atlas Copco equipment is built to last. Delivering superior performance in the most efficient and cost effective manner, our equipment is the driving force in your business. At Atlas Copco Service we are committed to delivering superior service to all customers in the Mining and Rock Excavation industry – whenever, wherever. We act as the most competent speaking-partner regarding the operation of your equipment. We enhance your productivity, profitability, and peace of mind, ensuring successful and sustainable business relationships. We always put safety and environmental considerations first in everything we do.

Technical support that stands out

Safety and environment

We know that the moments-of-truth are at delivery, upon start-up and in operation.

The concern for safety and the environment is more prominent today than ever before.

It is here that the difference between those who keep their promises and those who do not comes to light.

Atlas Copco’s concern for safety and the environment are essential components of our commitment to sustainable productivity.

Our dedication to providing the best possible support comes from recognizing the impact this has on success or failure. Wherever you are in the world, we strive to ensure that your service experience will be consistent.

290

Our equipment and genuine parts are designed to maximize the safety of personnel and mining operations, and to minimize environmental impact.

Blasthole Drilling in Open Pit Mining

service

Reliability and the highest availability Service agreements

Service kits

Remanufactured Components

Atlas Copco provides several types of service agreements to meet operational requirements and to secure your productivity.

To ensure your equipment remains fit for purpose, two things are needed: a good preventive maintenance schedule and a strict, genuine parts policy. Atlas Copco genuine parts help preserve the superior quality of the products throughout their entire life-cycle.

When you use Atlas Copco remanuactured compo-nents, you can rest assured that we will have the part you need – in stock – when you need it.

Extended warranty – Peace of mind, protecting your investment Parts-only plan – Genuine Atlas Copco parts and lubricants, guaranteed performance Preventive maintenance programs – Lower life cycle cost ensuring availability

Quality tested and inspected to ensure reliability and highest availability All required parts in one kit to minimize service time

Genuine OEM parts – Safe, reliable performance Superior warranty – Peace of mind – Lower operating cost Components readily available – Sustainable productivity Recycle – Reduce environmental impact

Total maintenance programs – minimize unplanned repairs Reliability centered maintenance products – Non-intrusive equipment health check

Blasthole Drilling in Open Pit Mining 291

Service

Optimization through tailored technology solutions

Healthy equiment through remote monitoring solutions

Atlas Copco has been acknowledged as one of the world’s most innovative companies. Our culture encourages creativity and passion to deliver energy-efficient and sustainable products and solutions.

Atlas Copco offers an advanced remote monitoring solution that enables our customers to identify problems prior to failure.

The Atlas Copco technology and energy efficiency product portfolio offers a wide range of application conversions, modifications and system and component upgrades for all equipment ranges. With a deep understanding of your operations, we provide tailored solutions that enhance and improve safety, performance and the environmental impact of your equipment. Benefits: • Extended equipment life cycles • Maximized equipment efficiency • Optimized equipment configuration • Guaranteed regulatory compliance

292

The Atlas Copco Remote Monitoring system integrates real-time monitoring, alarms, trends and production data. This data is filtered, analyzed and transformed into useful information regarding health and performance of your equipment based on the original manufacturers’ specifications. Some of the potential gains include: • Shift from emergency to planned maintenance through early detection of equipment degradation • Reduced maintenance costs through rationalized scheduled maintenance • Increased production through increased equipment reliability and performance

Blasthole Drilling in Open Pit Mining

service

Trained people perform Atlas Copco provides the very best training as part of our customer service, and appreciates the difference between operators who are already experts at handling our equipment and those who need additional training. We are more than willing to share the benefits of our long experience in the market and our complete toolbox of best practices, to the benefit of all our customers. Thanks to well-trained staff we are able to offer you Atlas Copco’s premium service support. Our service technicians go through a rigorous certification process, ensuring that you always get the best possible technical support close-by, readily available, whenever needed.

Just what you need, right when you need it Atlas Copco aims for a highly efficient supply chain enabling fast, demand-driven distribution. Together with our customers and our international supply chain network we continuously strive to supply through the most economic and environmentallyfriendly mode of transportation. Complete, accurate, on-time delivery of your order, every time, that’s our aim. Just what you need, right when you need it.

Anyplace, Anywhere, Anytime… Atlas Copco is a world leading supplier in the Mining and Rock Excavation sector. The Group delivers sustainable solutions for increased customer productivity through innovative products and services. Atlas Copco was founded in 1873. Today it has a global reach spanning more than 170 countries. We are committed to sustainable productivity which means that we do everything we can to ensure reliable, lasting results with responsible use of resources; human, natural, and capital.

293

simulator training

Drill simulator training Training drill rig operators with the aid of simulators is gaining in popularity, rapidly becoming the method of choice for mines around the world. Atlas Copco is a forerunner in driving this trend and now offers simulators for most of its surface and underground equipment, the latest of which is a new simulator for training operators of Pit Viper blasthole drills.

These modules provide extremely realistic and effective training for operating such large rigs as the new Pit Viper 235 in a safe and controlled environment. “The simulator will be used as part of our Master Driller program,” says Peter Lawrence, Technical Services Manager Parts and Services.“ The opportunity to learn in a realistic environment will allow operators to thoroughly familiarize themselves with these rigs before taking the controls in the real thing. “This means new operators can contribute more rapidly to a company’s operations.” Simulator training has proven to have a positive impact on performance and reliability as operators learn to avoid causing unnecessary wear and stress on key components. In addition, it enables training to take place away from the site so that working rigs can continue to focus on production. 294

Specification Measures Length

5m

197"

Width

4m

157.5"

Height

2.97 m

117"

Weight

2,500 kg

5,500 lbs

Electrical motion platform 3x3VAC-10% - 3x480VAC+10%, 50 Hz, Fuse 20AT 3x3VAC-10% - 3x480VAC+10%, 50 Hz, Fuse 20AT Computer rack cabin 110VAC – 230VAC, 50-60HZ, Fuse 10AT Humidity in operation Rel. humidity 85%, no condensation

Blasthole Drilling in Open Pit Mining

glossary

Glossary of terms A

Actuator – A motor or cylinder that is being put into motion by the flow of a hydraulic pump. Adapter-Adaptor – (both spellings are accepted) A device used to connect two different sizes or types of threads. It is used to connect rotary head spindles to drill pipe, drill pipe to stabilizers and stabilizers to drill bits. ANFO – Ammonium Nitrate Fuel Oil mixture: explosive most commonly used in blastholes. Angle Drill – Drilling a hole at a 0 to 30 degree angle from vertical (in five degree increments). Annulus – The space between the drill pipe and the outer diameter of the hole made by the bit. Annunciator – An electrical signaling device on a switchboard. API – American Petroleum Institute. ASME – American Society of Mechanical Engineers.

Bit, Roller – Also called a tricone bit. It usually has three conical rollers fitted with steel or tungsten carbide teeth that rip the rock loose using down pressure. Bits – Tools that pulverize formations so that material can be removed from the hole, generally three-blade, three-cone or percussion. Blasthole – A drilled hole used for purposes of excavation rather than exploration, geological information or water wells. Holes are used to load explosives for open pit mining, and are usually limited to 200 feet. Blasting – The act of igniting explosives in a borehole to produce broken rock. Blowdown – Term used when releasing compressed air from the receiver tank on a compressor when the drill is stopped. Blowdown Valve – The valve that opens when the drill is stopped and releases all the air pressure in the receiver tank. Bore – To make a hole in the ground with a drill. Borehole – The hole made by a bit.

ASTM – American Society of Testing Materials.

Box End – Fitting on the female end of a drill pipe. See Pin End.

Auto Lube System – A pump that provides grease to various components of the drill through hoses. It can be manual or computer controlled.

Breakout – Refers to the act of loosening threaded pipe joints, and of unscrewing one section of pipe from another, while coming out of the hole.

B

Bank – Vertical surface of an elevation; also called the face. Beco Thread – A coarse type of thread used on drill pipe. Bench – Work area on the top edge of an elevation. The work area for blasthole drills. Bit, Auger – A type of bit used to drill soft formations. It usually has a series of flutes on the outside. Bit, Claw – A wing-type bit that has multiple flukes. Sometimes called a drag bit. Bit Breaker – A device installed in the centralizer table to hold a bit stationary while the drill pipe is being removed from the bit by reversing the rotation. Also called bit basket. Bit, DHD – A solid, one piece bit with shaped tungsten carbide inserts in the face. Used in percussion drilling.

Breakout Wrench – A wrench, connected to a hydraulic cylinder, used to turn the upper piece of pipe while the lower pipe is being held by the fork chuck or sliding wrench. Bridge – An obstruction in the hole. Usually caused by a caving formation or something falling in the hole. Burden – Distance from the blasthole to the nearest face. Distance measured from the face to a row of holes. The material to be displaced. Buttons – Short, rounded teeth of sintered tungsten carbide inserts which serve as teeth in drill bits used for drilling very hard rock. Butterfly Valve – The adjustable inlet valve of the air compressor.

C

Cable – A strong, heavy steel, wire rope. Also known as wire rope. Used for pulldown

and pullback in the tower. Also used in hoisting. May be rotating or rotation resistant. Cable Reel – A device that holds the electrical power cable on electric driven blasthole drills. Carousel – A rotating device that holds extra drill pipe. It can be moved under the rotary head to add and remove drill pipe from the string, or the rotary head moves over it. Carbide, Tungsten – W2C. A very hard compound used in inserts in rock bits. It has a very high melting point. It is very strong in one direction but very brittle in another. Catwalks – Walkways around a working area of a drill. Cavitation – The pitting of a solid surface by the formation of low pressure bubbles formed in the fluid. Air being allowed into the inlet of pumps. Centralizer Bushing – A circular ring installed around the drill pipe in the drill table to keep the pipe aligned properly with the rotary head. It usually has a replaceable insert in the center. Chain Wrench – A special wrench, consisting of a chain section and a metal vee section, with jaws, that grips the drill pipe and/or the DHD to tighten or loosen the connections. Collar the Hole – Opening at the top of the blasthole; the mouth where rock has been broken by blasting. Usually the first few feet of the blasthole that are cracked and broken. Compressor – An asymmetrical rotary screw driven device for compressing air. May be single- or two-stage, depending on the discharge pressure. Console – The panel that contains most of the drill’s controls. Also called the operator’s panel. Conveyor – Equipment used to carry material to crushers and screens for reduction and separation. Cooler (Hydraulic oil Cooler (HOC), Compressor Oil Cooler (COC)) – All drills have a cooler or coolers for the hydraulic fluid and the compressor oil. The engine radiator is also sometimes referred to as an engine cooler. Coring – The act of procuring a sample of the formation being drilled for geological information purposes.

Blasthole Drilling in Open Pit Mining 295

Glossary

Coupling – A connector for drill rods, pipe or casing with identical threads, male or female, at each end. Cribbing – A set of wooden ties or metal plates used to add surface area to the jack pads to prevent the pad from sinking into the ground. Also called blocking. Crown Sheaves – The upper sheaves in a tower that supports the cable that connects to the rotary head. Crosshead – The outer metal can surrounding the leveling jack cylinders. The crosshead slide is the lower portion that connects to the bottom of the cylinders and the crosshead cap is the flanged piece on top of the crosshead. Crusher – Device used to reduce broken rock to a smaller fragment size. Cut (verb) – Process of excavating material to lower the level of part of an elevation. Cut (noun) Part of an excavation of a specified depth and width. Cuttings – Particles of formation obtained from the hole during drilling operations.

D

Decking – Process of alternating explosives with inert material in a blasthole to properly distribute explosives or reduce vibrations. Also refers to the metal catwalks around the outside of the drill. Delay Interval – Elapsed time between detonation of individual blastholes in a multiple hole blast. Derrick – A tall framework over a drilled hole used to support drilling equipment. The part of the drill that contains the feed system and the rotary head. See Tower and Mast.

Dressing a Bit – Sharpening DHD drill bits with a grinder to shape the carbides. Drifter – An out-of-the-hole drill that rotates the drill rod and provides a percussive force, by means of a striking bar, through the rod to the bit. Drill – A machine for drilling rock or unconsolidated formations. Also called a rotary drill. The act of boring a hole in the ground. Drill Collar – A heavy, thick-walled section of pipe used to add drilling weight to the bit and stabilize the drill string. Drill Rod – See Drill Pipe. Hollow, flush-jointed, coupled rods used on small percussion type rock drills. Drill Pipe – Hollow tubing, specially welded to tool joints. Drill/Propel Valve – A switch that shifts the diverter valves to allow pump flow to go from drill functions to propel motors. Drill String – The string of pipe, including subs, stabilizers, collars and bit, extending from the bit to the rotary head, that carries the air or mud down to the bit and provides rotation to the bit. Driller (Operator) – The employee directly in charge of a drill. Operation of the drill is their main duty. Drill Table – The area at the bottom of the tower that contains the centralizer bushing or master bushing that the drill pipe travels through. Dust Collector – A vacuum device with a hose attached to the dust hood that pulls cuttings away from the hole and deposits them to the side of the drill.

Fish – An object accidentally lost in the hole. Fishing – Operations on the drill for the purpose of retrieving the fish from the hole. Fishing Magnet – Magnet run in the hole on non-metallic line, to pick up any small pieces of metal. Fishing Tools – Tools of various kinds run in the hole to assist in retrieving a fish from the hole. Overshots fit over the pipe while taps fit inside the pipe. Flats – Machined areas on the side of drill pipe or other components where wrenches can be installed to hold or break the joints. Some pipe have two flats, others have four flats. Floor – Level area at the base of a bank or face. Fork Chuck – The handheld or “flop-down” wrench used to hold the top of the pipe on the drill table while adding or removing other pipe.

H

Hammer – A different name for a Down Hole Drill. Hammer Bushing – Split bushings installed in the drill table to allow the DHD to start the hole in a straight line. It is removed once the DHD is below the table. Also called DHD bushings. Haul Distance – Distance material has to be moved, such as from a cut to a fill. Hauling Equipment – Trucks and other conveyances for moving material. Also called haul trucks. Hazard – Any condition of the drilling equipment or the environment that might tend to cause accidents or fire.

F

Hoist – Device used to pick up drill pipe and other heavy objects. See Winch.

Feed Cable – Cables, anchored on the top and the bottom of the tower, that pass through the traveling sheave block and connect to the top and bottom of the rotary head. They are adjusted by tightening the threaded rods on each end.

Hoist Plug – A lifting device installed in the box end of a tool. Opposite of lifting bail.

Dip – The angle between a horizontal plane and the plane of the ore vein, measured at right angles to the strike.

Feed Chain – Heavy duty chain links connected to the rotary head through upper and lower sprockets and the traveling sheave block. They are adjusted similar to a cable.

Hose, Drilling – Connects rotary head to top of hard piping to allow movement of rotary head. Also called standpipe hose.

Diverter Valve – A two position, three-way, valve that allows one hydraulic pump to perform two separate functions.

Fill – Process of moving material into a depression to raise its level; often follows the cut process.

DHD – Down Hole Drill. An air driven, piston powered device for drilling hard rock. It is also called a hammer. DHD Bushings – The split bushings used to maintain alignment of the DHD while passing through the drill table. See Split Bushings. Differential Pressure – The difference in pressure between the inlet and outlet of a component, i.e., a cooler.

296

Face – Vertical surface on an elevation. Also called bank.

Hole – A bore made by rotating a bit into the ground.

Hydraulic Cylinders – Double acting cylinders that are extended and retracted to perform various functions on a drill. They are powered by hydraulic fluid from a pump. Blasthole Drilling in Open Pit Mining

glossary

Hydraulic Motors – Piston or vane type motors, driven by hydraulic pumps, that rotate various devices on a drill. Hydraulic Pumps – Piston, vane and gear type hydraulic pumps that provide flow for the various actuators on the drill. Hydrostatic Head – The pressure exerted by a column of fluid, usually expressed in pounds per square inch.

I

Inclinometer – An instrument for measuring the angle to the horizontal or vertical of a drill hole or vein. I.W.R.C. – Abbreviation for Independent Wire Rope Center. This refers to the type of construction of wire rope. This wire rope center is in effect a separate wire rope in itself that provides a core for the line and prevents it from crushing or breaking. Interstage Pressure – The air pressure present between stages of a two-stage compressor while the compressor is making air.

J

J Wrench – Specially shaped wrench to fit the backhead of a DHD. Used to hold a DHD on the table or to remove the backhead from the wear sleeve.

K

Kelly Bar – A fluted or square drill pipe that is turned by a rotary table using a set of pins.

L

Leveling Jacks – Hydraulic cylinders mounted in a crosshead that raise and lower the drill. Also referred to as outriggers or stabilizers. Lifting Bail – A threaded cap for picking up pipe, bits, DHDs and stabilizers. It screws on the pin end. Some bails have a swivel hook while others have solid tops. Opposite of hoist plug. Loaders – Large, front end bucket equipment used to pick up material for loading in various types of hauling equipment.

M

Main Frame – The welded component of a track mounted drill. The truck frame on a wheeled drill. Main Shaft (axle) – The tube connecting the tracks of a blasthole drill to the main frame. Makeup – The act of tightening threaded joints. Making a connection.

Making Hole – The act of drilling. Making Up a Joint – The act of screwing a joint of pipe into another joint or section of pipe. Manifold – A pipe or chamber that has several openings for hose connections.

Pipe Dope – Special lubricant used to protect the threads on pipe joints. See Thread Lube. Pipe Support – A device that holds the lower section of pipe in place while connecting to the next joint with the rotary head when angle drilling. Also called rod support.

Mast – A vertical structure. See Derrick.

Pit – An excavation in the ground for the removal of mineral deposits.

Micron -:- Mu – A unit of length equal to one millionth of a meter, or one thousandth of a millimeter. About 4/100,000 of an inch.

PLC – Programmable Logic Controller. A device that monitors many aspects of a drill’s operation.

Mid-Inlet Swivel – Device for removing cuttings from the hole while drilling with reverse circulation equipment.

Potable Water – Water that is safe to drink.

Mine Plan – Plan for making cuts and creating elevations, benches for efficient removal of material. The mine plan considers a variety of factors, including the type and location of material, the size and number of shovels, loaders, and hauling equipment, haul distances, blasthole patterns, etc.

Powder Factor/Specific Charge – Relationship between the weight of explosives in a blasthole and the volume of materials to be displaced. It is measured in pounds per cubic yard or kilograms per cubic meter. Power Pack Base – The welded channel frame that contains the prime mover, the compressor and the hydraulic pumps and gearbox.

O

Power Pack – The complete sub-assembly of base, engine, compressor, and hydraulic drive.

Open Hole – Any uncased portion of a hole.

Presplitting – Process of drilling a line of small diameter holes spaced relatively close together, generally before drilling a production blast, and loaded with light explosive charges to create a clean, unbroken rock face.

Oscillation Yoke – The beam connecting each track of a blasthole track drill with the main frame that allows the tracks to move independently up and down.

Operator – The person who performs the drilling operation with the drill. See Driller. Overburden – Any unconsolidated material lying on top of the bedrock or the coal seam.

P

Parasitic Load – The load imposed on the engine by the direct connection of the compressor and main pump drive during starting. Pattern – Layout and distances between blastholes, specifically including burden and spacing. Penetration Rate – Speed at which a bit advances while drilling, usually measured in feet per hour. Instantaneous or drilling penetration rate is the rate only while drilling. Overall penetration rate is the same as the production rate (see production rate).

Production Rate – Penetration during a given reporting period. This rate includes all lost time including maintenance, breakdowns, long moves, inclement weather, etc. Propel – To cause to move forward or onward. To drive or tram. Protectors, Thread – Steel or plastic covers to cover the box and pin ends of drill pipe when they are not being used. Pump, Water Injection – Pump used to pump water into the drill air stream to keep the dust settled and to assist in flushing the hole. Pullback – The force available to remove the drill string from the hole.

Percussion Drill – Drill that chips and penetrates rock with repeated blows.

Pulldown – Force exerted on the drill bit by the thrust of the drill rig and from the weight of the drill string.

Pin End – Fitting on male end of drill pipe. See Box End.

Q

Pioneer Work – Drilling in rough, broken or inclined areas. Removing the original layers of dirt and rock.

Quick Fill – A centralized service station that connects to various systems on the drill to allow remote filling of engine oil, compressor oil and hydraulic oil.

Blasthole Drilling in Open Pit Mining 297

Glossary

R

Raise – A mine opening, like a shaft, driven upward from the back of a level to a level above, or to the surface.

Sliding Fork – A wrench that slides around the flats of the drill pipe to hold the section lower. Controlled by hydraulic cylinder(s). Used in place of a fork chuck.

Reamer – Bit-like tool, generally run directly above the bit to enlarge and maintain a straight hole.

Slips – Used in the rotary table to hold and break out drill pipe. Also used to hold casing in the table.

Reservoir –The tank used for storing the hydraulic oil used in the hydraulic system.

Spacing – Distance between blastholes measured parallel with the face.

Reverse Circulation Drilling – Using a double wall pipe to force air/water down the hole and removing the cuttings between the two pipes. See Mid-Inlet Swivel.

Spear – Tools of various design that are screwed or wedged inside of bits, pipe, etc., that are lodged in the hole. See Fishing Tools.

Rod Changer – A device that holds extra drill rod (pipe). See Carousel.

Spindle – The short section of pipe that rotates within the rotary head, and protrudes out.

Rotary Drilling – The method of drilling that depends on the rotation of a column of pipe to the bottom of which is attached a bit. Air or fluid is circulated to remove the cuttings.

Speed Switch – An electronic device that changes states when the engine reaches a certain speed. Used to control dual oil pressure switches.

Rotary Head – A movable gearbox used to provide rotation to the drill string. It is connected to the feed chains or cables on each end and to the drill string through the spindle.

Split Bushings – The removable bushings that allow the DHD or Stabilizer to pass through the drill table while drilling a straight hole. See DHD Bushings.

S

Safety Hook – Attached to the end of a hoist line to secure the hoist plug or lifting bail. Has a safety latch to prevent the load from slipping off the hook. Scales – Equipment used to determine the weight and value of material being transported from a quarry. Screens – Devices used to separate broken material into groups of similar size. Shock Sub – A device used to isolate the shock of drilling from the rotary head. It is made of hard rubber layers mounted inside of steel outer rings. Single Pass Drill – Drill rig with a long tower that permits drilling a blasthole without stopping to add drill pipe (rod). Uses a Kelly in place of regular pipe. Uses a rotary table to turn the Kelly instead of a rotary head. Stemming – Material of a specified depth added on top of a powder column to confine the blasthole and make the explosion more efficient. Strip Mine – A large section of land used to remove coal deposits.

Stabilizer, Drill Pipe – Heavy -walled pipe having special spiral or fluted ribs extending around the diameter, within 1/8 “to 1/4” of hole size. Most stabilizers are fitted just above the bit, while in-line stabilizers keep the hole straight. Standpipe – Part of the circulating system. The hard and flexible piping from the main valve to the flexible hosing leading to the rotary head. Water injection, DHD oil and foam are injected into this line. Static Water Level – The distance from the top of ground down to the standing water level. Strike –The bearing of the outcrop of an inclined bed or structure on a level surface. See Dip. Stuck In The Hole – Refers to drill pipe inadvertently becoming fastened in the hole. Subdrilling – Bottom portion of a blasthole drilled below the floor level to permit upward displacement of material and thereby prevent a toe at the bottom of a face.

Swivel – A coupling on top of the rotary head to allow the spindle to rotate while the main hose remains stationary.

T

Table Drive – Drill design that locates the drill pipe rotation mechanism on the drill deck in a stationary position instead of using the rotary head. Threaded and Coupled Casing (T&C) – Steel casing using a coupling between each section of pipe. Thread style is right hand, fine thread. Thread Lube – A special compound used to lubricate the threads of drill pipe. See Pipe Dope. Tongs – A type of wrench used to make up and break out drill pipe using external forces, such as hydraulic cylinders or cables. Tool Joint – A drill pipe coupler consisting of a pin and box of various designs and sizes. Deephole drills normally use API style threads, while blasthole drills normally use Beco style threads. Top Head Drill – Drill design that locates the drill pipe rotation head in the drill tower. It moves up and down with the drill string. See Rotary Head. Torque – A turning or twisting force. A moment caused by force acting on an arm. A one pound force acting on a one-foot arm would produce one lb-ft of torque. Tower – A tall, slender structure used for observation, signaling or pumping. Term used to indicate the derrick on a blasthole drill. See Derrick and Mast. Turning To The Right – Slang term for making a hole. Tram – A cable car or a four-wheeled open box in a coal mine. See Propel. Trammed – To move in a tram. Tramming – Process of moving a drill. See Propelling. Traveling Sheave Block – A series of sheaves, connected to the feed chains or cables, that are moved up and down the derrick by the feed cylinders.

Shot – A charge of high explosives deposited in a series of holes to shatter the rock.

Sub – A coupling with different type or diameter of threads at either end. The term pin denotes a male thread, and box, a female thread. To connect two components with different threads. See Adapter.

Twist Off – To twist a joint of pipe in two by excessive torque applied by the rotary head or rotary table.

Shutdown – A term that can mean the end of the shift or workday or an unplanned stopping of the drill due to a system failure.

Supercharge Pressure – Inlet oil pressure to the main pump(s) that has been pressurized to prevent cavitation.

UL88 – The pneumatic valve that controls pressure and volume on a high-pressure compressor system.

298

U

Blasthole Drilling in Open Pit Mining

glossary

Undercarriage – The means of moving a track type vehicle. It contains the track frame, rollers, grousers, rock guards, drive sprocket, propel motors and planetary drive. Uphole Velocity – The speed (in feet per minute) that the cuttings travel out of the hole. This is dependent on the bit size, the compressor size and the pipe size.

W

Washpipe – Hard surfaced steel tubes inserted in swivels to allow rotation of drill string and prolong life of packing. They are replaceable in most swivels.

Weight On Bit – In rotary drilling, a specified weight is required on the bit for maximum performance. A gauge on the console is calibrated to correspond to the drill string weight. Winch – A stationary hoisting machine having a drum around which a rope is wound. Wiper, Pipe – An annular rubber disk for wiping drill pipe clean of cuttings when it is being withdrawn from the hole. Wire Rope – Rope made of twisted strands of steel wire. Also called cable.

Water injection – A method of rotary drilling where water is dispersed in the air while drilling. Blasthole Drilling in Open Pit Mining 299

Atlas copco

Where to find us

Please contact your local Atlas Copco CustomerCenter. or visit www.atlascopco.com and select country, or contact: Atlas Copco Drilling Solutions LLC, Garland, Texas, USA Telephone: +1 (972) 496 7400

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Blasthole Drilling in Open Pit Mining

Advantage — Pit Viper

Your purchase is just the start The Pit Viper blasthole drills have earned a reputation for productivity and smart design. To enhance that, Atlas Copco offers training for drill rig operators on simulators—giving an extremely realistic experience in a controlled environment. Ergonomics have always been a part of the Pit Viper design, but this training keeps operators safe while enabling them to learn without wear and stress on rig components in the field. Atlas Copco is much more than a rig sales company. We also offer complete service packages, and this training opportunity to keep the advantage on your productivity. If you need more reasons to invest in a Pit Viper, find out more at www.atlascopco.com/blastholedrills.

Advantage – Pit Viper

Interested in increasing your productivity? The Pit Viper blasthole drills have earned a well-   deserved reputation for dependability and productivity. Operator safety and ergonomics also contribute to their high long-term value. Whether you are searching for simple and rugged, or advanced and automated, the Pit Viper will be a strong contender. With the Atlas Copco Rig Control System (RCS) option you can start with a simple basic concept and still have the flexibility to add advanced functions later. Atlas Copco also offers complete drill string and service packages tailored to your specific requirements.

Printed matter no. 58 388 351

If you need more reasons to invest in a Pit Viper, find out if you can take advantage of single-pass drilling! Visit www.atlascopco.com/blastholedrills today to learn more about the Pit Viper series.

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