Impacts of Coal Mine Fire on Environment

Impacts of Coal Fires on the Environment Ritesh Kumar **, Gaurav Chakrabarty *, S. K. Roy** and R. R. Singh** *Msc Geo-informatics, BIT Mesra, Ranchi **Scientist, CIMFR, Dhanbad

Abstract Coal fires burning around the world are an environmental catastrophe characterized by the emission of noxious gases such as carbon monoxide, carbon dioxide, sulphur dioxide and nitrogen oxides, particulate matter, and condensation by-products. Underground fires ignited by natural causes or human error are responsible for atmospheric pollution, acid rain, perilous land subsidence, and increased coronary and respiratory diseases. They consume a valuable energy resource, destroy floral and faunal habitats, and promote human suffering as a consequence of heat, subsidence and pollution. This paper provides a brief overview of the deadly impacts of coal fires on the environment, discusses some of the largest coal fires in the world and finally it deals with remote sensing technology used for detecting and preventing coal fire. (Key words: coal fires, environmental problems, Jharia coalfield, remote sensing) Introduction to Coal Fire Coal fires are an environmental and economic problem of international magnitude (Figure 1). Coal fires occur in many countries worldwide viz. US, Australia, South Africa, Indonesia, China, India, etc. (Saraf et al., 1995; Tetuko et al., 2003). Figure 1 shows the spread of coal fires around the world. The largest coal fires, however, are reported in India, China, USA, Indonesia and South Africa (Bell et al., 2001; Stratcher & Taylor, 2004; Rosema et al., 2001). Basically, a mine fire is where something usually coal has caught fire and is steadily burning away the valuable non-renewal resources of the world. In other words, the term coal fire refers to burning or smouldering of coal seam, coal storage pile or coal waste pile. The adsorption of oxygen at the outer and inner surface of coal is an exothermic reaction leading to an increase in temperature within the coal accumulation (Rosema et al. 1999). If the temperature of a coal accumulation exceeds approximately 80 0 C, the coal can ignite and start to burn. This process is called

“spontaneous combustion”. Further, mining activities, mining accidents and careless mining techniques are some of the reasons of the origin of coal fire. Coal fires can burn for very long periods of time from months to centuries, until the seam in which they smoulder is exhausted. They propagate in a creeping fashion along mines shafts and cracks. Because they are underground, they are extremely difficult and costly to reach and extinguish.

Figure 1: Coal Fires around the World (Source: Gangopadhyay, P. K. and Dutt-Lahiri, K., 2005) Origin of Coal Fire Coal fires are generally ignited by mine related activities such as cutting and welding, explosives and electrical work, or transmission of surface fires to culm banks or coal seams by lightening, forest or bush fires or due to spontaneous combustion of coal. Coal reacts with atmospheric oxygen even at ambient temperatures and this reaction is exothermic. If the heat liberated during the process is allowed to accumulate, the rate of the above reaction increases exponentially and there is a further rise in temperature. When this temperature reaches the ignition temperature of coal, the coal starts to burn and the phenomena is described as spontaneous combustion. The temperature at which

the oxidation reaction in coal becomes self sustaining and spontaneous combustion occurs varies depending on the type (nature and rank) of coal and surrounding conditions of heat dissipation. In poor quality coal and where the heat retention is high the coal and carbonaceous material may start burning at temperatures as low as 30-40° C. According to US department of energy, many spontaneous fires start in storage facilities including open air stock piles, coal bunkers, and silos. The DOE attributes combustion to numerous factors. These include improperly loaded and compacted storage facilities that promote the diminution of coal into highly combustible fines and also storage for prolonged period of times, which promotes exothermic oxidation reactions in high sulfur coals. The major reasons for occurrence of coal fire due to spontaneous combustion are: •

Thick coal seam

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Plenty of coal mines in the goaf

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Presence of contiguous seams

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Coal handling procedures allowed for long-time retention of coal which increases the possibility of heating.

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New coal added on top of old coal created segregation of particle sizes, which is a major cause of heating.

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Too few temperature probes installed in the coal bunker resulted in an excessive period of time before the fire was detected.

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Failure of equipment needed to fight the fire (drag chain conveyer).

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Ineffective capability and use of carbon dioxide fire suppression system.

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Delay in the application of water.

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Inadequate policies, procedures, and training of personnel which prevent proper decision making, including the required knowledge to immediately attack the fire.

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Failure to learn lessons from past occurrences from coal bunker fires.

Effects of Coal Fire Frankly saying it’s a disaster. Coal fires burning around the world are an environmental catastrophe characterized by the emission of greenhouse gases (methane, volatile matter and carbon dioxide) noxious gases, particulate matter, and condensation by-products. Underground mine fires ignited by natural causes or human error are responsible for atmospheric pollution, acid rain, perilous land subsidence, and increased coronary and respiratory diseases. They consume a valuable energy resource, destroy floral and faunal habitats, and promote human suffering as a consequence of heat, subsidence and pollution (Whitehouse and Mulyana 2004). Field measurements and laboratory analysis reveal that during burning, these fires spew carbon monoxide, benzene, toluene and dozens of other toxins into the atmosphere and soil, along with the greenhouse gases methane during heating of the coal and carbon-dioxide. The per-annum global emissions of the components in the coal fire gas have never been quantified. However the toxins have made people sick, sometimes even proved fatal. The various components like acids, aerosols, and toxic particles released from coal fires may be transported to distant places. For instance, in China such pollutants have affected adversely 88 cities. Similar sulfate aerosols released from fires of mines in Jharia, India, have reduced the intensity of solar radiation reaching the Indian subcontinent by 15% (Stracher & Taylor, 2004). Following are some of the pictures (Figure 2a to 2f) illustrating coal mine fires around the world:

(a)

(b)

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(d)

(e) (f) Figure 2: Typical coal fires in the mining regions around the world Source: (a) Northern China (http://www.ehponline.org/docs/2002/110-5/tirelava.jpg); (b) Wuda Region in North Central China (Kuenzer, C. et al., 2007); (c) Olyphant, Pennsylvania, USA (http://www.undergroundminers.com/olyphantfire31.JPG); (d) USA (http://www.centraliaminefire.com/archive.html) ; (e) Jharia, India (Stracher, G. B., 2007); (f) Jharia, India (Stracher, G. B., 2004).

On the other hand, according to Glen B. Stracher, coal fires have some constructive effects in the sense that they transform landscapes, frequently generating new chemical products at the same time. Sinkholes, valleys, and slump blocks produced by volume-reduced coal during burning, chemically altered or pyro-metamorphic rocks and paralavas are the most obvious features of modern fires. Several direct and indirect impacts due to coal fires on environment can be listed as below: 1.

Emission of noxious gases like CO, NOX & SOX and the particulate matter that pollute the local atmosphere,

2.

Emission of greenhouse gases such as CO2, and CH4 further aggravating the global warming problem,

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Loss of non-renewal valuable resources that has become life-line of every individual in modern times,

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Loss of flora and fauna,

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Subsidence causing damage to life and properties as well as change in the local drainage pattern,

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Air pollution problem,

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Land degradation,

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Temperature increment of surrounding areas and

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Increase in production cost due to deployment of man, money and machinery for fire estinguishing and difficulties in mining operations.

Largest Coal Fires in the World: Some Cases Some of the largest and oldest coal fires in the world are dealt below: China China leads the world in coal production. Its reserves are concentrated in the Xinjiang Uygar and Ningxia Hui of north-west and north-central China respectively. Coal fires burning throughout these regions and across northern China started by lightening, spontaneous combustion and mining operations on all scales. The coal fires in China is consuming up to 200 millions tons of coals per year and accounts for 2-3% of the annual

world emissions of atmospheric CO2 from burning fossil fuels (Figure 3) (Discover, 1999).

Figure 3: Coal Fire in Northern China (Source: Gangopadhyay, P. K. and Dutt-Lahiri, K., 2005) In the Rujigou coalfield of Ningxia, underground coal fires are responsible for land subsidence and the release of hydrogen sulfide into the atmosphere (Discover, 1999). The length, width and depth of the surfacial cracks induced by subsidence are as much as several kilometers long, tens of meters wide, and hundreds of meters deep. These cracks promote subsurface burning by providing a conduit through which oxygen can circulate to support combustion (Figure 4).

Figure 4: A collapsing coal seam burns in an open pit mining area in the Rujigou Coalfield in China (Source: http://www.ehponline.org/docs/2002/110-5/tirelava.jpg)

As a consequence of these, the atmospheric pollution in China is among the highest in the world. Acid rain from SO2 and NOx is a problem in 88 major Chinese cities and the problem has spilled over to Taiwan, Japan, Korea, and Philippians (World Resource Institute, 99). The economic loss from burning coal resources in China alone is estimated to be as high as $125-250 million (Prakash, 2003). These problems are compounded by the rise of lung diseases, stroke, heart diseases, and chronic obstructive pulmonary disease in China linked to coal gas and particulate emission (Stracher, 2004). Pennsylvania, USA Coal mining in Pennsylvania began in the mid 1700’s in response to colonial America’s demand for iron. Since then, Pennsylvania coal has supplied energy to the United States and countries abroad (Pennsylvania Department of Environment Protection). Coal fires in Pennsylvania have been recorded since 1772 (Glover, 1992), but the major fire occurred in 1869 when a ventilating furnace ignited wooden supports in the Avondale mine in Plymouth, suffocating 110 men trapped below ground (Roy, 1876). Since then, coal fires across Pennsylvania have destroyed floral and faunal habitats, consumed buildings, emitted toxic fumes into houses, contributed to different illness, induced land subsidence and many more. Figure 4 shows one of the coal fires in Pennsylvania, USA.

Figure 5: Coal Fire in Centralia, Pennsylvania, USA (Source: http://www.offroaders.com/album/centralia/photos22.htm)

One of the underground mine fire in the US is the Centralia mine fire (Figure 6). The Centralia mine fire began when the Centralia Borough Council decided to burn trash to reduce volume of and control rodents in an abandoned strip-mining cut used as an unregulated dump at the edge of the town. Burning trash ignited anthracite in the Buck Mountain seam concealed behind the refuse and the fire spread along the seam to tunnels beneath Centralia (Memmi, 2000).

Figure 6: A Mine Fire in Centralia, USA (Source: www.offroaders.com/album/Centralia/Centralia.htm) Yet another, Percy mine fire in Youngstown, Pennsylvania has been burning underground for over 30 years. Like the Centralia fire, it apparently started when people ignited trash near a coal seam (Glover 1988). Jharkhand, India The Jharia Coalfield is located in Dhanbad district, north of Damodar river, in the state of Jharkhand. It is largest coalfield in India and the country’s primary source of coking coal. The Jharia coalfield consists of 23 large underground and nine open cast mines. The mining activities in these coalfields started in 1894 and had really intensified in 1925. The history of coal fires in Jharia can be traced back to 1916 when the first fire was detected. At present more than 70 mine fires are reported from this region. Figure 7 below shows the fire prone areas of Jharia Coalfield region.

Commercial coal mining in India began in 1774. Production was at first slow, but it increased with the advent of steam locomotives in 1853 (Ministry of Coal Mines, 2003). The mines were later nationalized between 1971 and 1973. Today, India is the third largest coal producing nation in the world. As such the issue of coal mine fire is of great importance when talking in prospect of economic and social context. Fires have beset Indian coalfields since the earliest days of mining. Surface and sub-surface fires burning throughout the Jharia Coalfield comprise one of the largest coal mine fires complexes in the world. The first coal fire in Jharia Coalfield broke out at Bhowrah in 1916. By the 1960’s, numerous fires spread throughout the entire coalfield, with flames locally reaching heights of 20 m. Most coal fires in JCF were ignited by spontaneous combustion of coal subsequent to opencast and deep mining. Exploitation without fire-prevention codes prior to nationalization was responsible for these fires. In addition, the illegal distillation of alcohol in abandoned underground mines purported to be the origin of some of the JCF fires. Figure 8 shows one of the fire affected area (Kusunda) of Jharia Coalfield, India.

Figure 7: The Jharia Coalfield with fire prone areas (Source: www.gisdevelopment.net/proceedings/mapindia/2006/student/20oral/images/ma06159_2.jpg)

Figure 8: Coal Mine Fire in Jharia Coalfield (Source: Stracher, G. B. and Taylor, T. P., 2004)

Following pictures (Figure 9) provides a glimpse of the catastrophic coal fire in Kusunda area of Dhanbad district:

(a)

(b)

(c)

Figure 8: A Glimpse of the Catastrophic Coal Fire in Kusunda Area of Dhanbad District (Source: Author) The above three pictures are taken in Kusunda coal field area where open cast mining is going on. The area is really under fire and the persons working over there have life-risks. Smokes are coming out from the mine overburden dumps too which includes

many noxious gases, toxic fly ash that pollute air, water, and soil which ultimately are promoting human diseases of heart and lungs. Following pictures (Figures 10a to 10c) shows the smokes puffing out of mine overburden dumps in Kusunda and the surface temperature problem faced by the worker there.

(a)

(b)

(c)

Figure 10: Smoke and the Hot Surface problems faced by the people in Kusunda. (a) Smoke in the Overburden Dumb and (b & c) Vapour Formation after water is sprinkled to cool the hot surface for workers to work there (Source: Author) The According to National Center for Atmosphere Research in Boulder, Colorado, JCF fires contribute to atmospheric sulfate aerosols derived from industrial emissions. These aerosols absorb or scatter solar radiation, thereby reducing the amount of sunlight that reaches the earth’s surface (Collins 2000). Singh et al. (2007) have studied mine fire indices and their application to Indian underground coal mine fire. Stracher and Taylor (2004) have also studied Jharia coal fire problem in detail. Figure 11 and Figure 12 show yet another coal fires in Jharia Coalfields. From the Figure 11 one can see how in the midst of extreme danger workers carry out the mining activities and Figure 12 shows the efforts being made to fight the coal fire in the Jharia region using crude techniques.

Figure 11. Coal mining efforts in the midst of extreme danger and minimal mining profits. (Source: Michalski, 2004)

Figure 12: Crude techniques for combating coal mine fires in the Jharia Coalfield. (Source: Michalski, 2004)

Detection of Mine Fire using Remote Sensing Technology To prevent the coal mine fire from damaging life and property, we got to identify it first and the direction in which it is spreading. To detect and identify the mine fire we can use the remote sensing techniques (Chatterjee 2006, Prakash et al., 1995, Reddy et al. 1993 and Bhattacharya 1991)). Researchers such as Slavecki, 1964, Knuth et al., 1968 Knuth, 1968 and Green & Moxhani, 1968 and others throughout the world have tried to make use of thermal infrared imagery to detect subsurface coal fires. Subsidence has been identified due to underground mine fire in northwest China using Thermal, Microwave, and optical satellite data (Prakash et. al. 2001). Research using synthetic aperture RADAR (SAR) to identify subsidence is currently being conducted at ITC (Prakash, 2003). Optical and thermal images acquired by the Beijing Remote Sensing Corporation (BRSC) and heat measurements from surface and subsurface detectors have been used to determine the coal fire size, depth of greatest intensity, and burning direction (Vekerdy et. al 1999). Temperatures exceeding 8000C for surface fires have been recorded with ground based thermal detectors. Combining the information acquired for numerous fires with GPS and geologic data, ITC scientists together with BRSC designed a PC-based geographic information system COALMAN (Vekerdy et, al. 2000). COALMAN is used to assist Chinese fire fighters in the field by generating a time series of fire fighting maps and subsurface images of fire. In Jharia, several forms of technology have been used so far to investigate mine fires. Some of the measures for controlling coal fires in Jharia coalfields include, bull dozing, leveling and covering with soil and overburden dumps to prevent the entry of oxygen and to stabilize the land for vegetation. Use of sand as stowing material for filling the vacant spaces in the abandoned mines so as to stop the entry of oxygen and also to prevent the subsidence is another method being used in the Jharia region. Nowadays, fly ash is being experimented and used as a stowing material. However, use of Remote Sensing and Geographical Information System is the latest method that is being used to identify and understand the fire problems of Jharia Coalfields. Multi-spectral and temporal data from the LANDSAT Thematic Mapper

(TM), reveal that subsurface fires are more extensive than surface fires (Prakash et. al 1997, Prakash et al. 1999). Surface fire anomalies detected with TM-6 thermal infrared data signify subsurface fires at depths of 45-55m (Saraf et. al 1995). Alternatively, subpixel corrections for TM-5 and TM-7 short wave-infrared data reveal surface fires ranging in temperature from 342 to 7310C. In addition to remotely acquired TM data, BCCL has integrated GPS data into a GIS to locate, map, and monitor surface fires.

Conclusion Coal fire is a catastrophe in true sense, endangering life, property and the resources itself. Whether, we pick up the case of china, Pennsylvania or India (Jharia), just three words flashes in our brain- death, decay and destruction. The impacts of coal fire come into picture with toxic gases, subsidence, particulate matters, destruction of floral and faunal habitats and many more including the loss of invaluable non-renewal resources. In short, coal fire is affecting air, water, soil and the entire ecosystem and therefore, should be controlled at the earliest in order to prevent any major disaster in the near future. Surface and sub-surface coal fires are a widespread problem of international magnitude. Such problems need to be addressed more seriously as several environmental and economic problems are directly linked to it. In fact, in the present time remote sensing technique can prove to be an effective tool in detecting and monitoring coal fires and perhaps in checking huge economic loss and environmental disasters.

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