Summary Tailings Design

Summary: Design of Tailings Dams and Impoundment By: Chamel J. Ruperez Tailings are being treated as important as its commodities in a mining industry because the negligence of it will greatly affect its surrounding environment. Thus, tailings are being impounded to mitigate its negative effect on the environment. Impoundment of tailings will involve the design process, which requires a thorough planning and construction in consideration of its operation and closure issues together with requisite technical aspects. As the world become more environment conscious, the design processes, as well as the alternatives tailings management technologies, are continuously developing to meet these environmental requirements and demonstrating good mining practice. The discovery of mining, as time passes, gave birth to the tailings in the early 1500’s. The introduction of steam power greatly increased the capacity of grinding mills thus increasing tailings. Later in 1800’s, froth flotation and cyanidation increase the gradually end and uncontrolled disposal of tailings in 1930. These gave the awareness on handling of tailings. Because of this realization, many fundamental dam engineering designs, geotechnical engineering and related disciplines are adopted in 1950-1960 leading to an inventions of earthquake-induced liquefaction tailings dams in 1965. Further, tailings dams are designed in mitigation on negative environmental impacts. These designs are being standardized by the government and some nongovernment organizations to be implemented internationally. Site characterization is the major factor to be determined in designing and managing tailings impoundment failure risk. This was carried out on a thoughtful site investigation to develop a thorough understanding of site geology. Due to technological advances, site investigations are carried out with more reliable data in the applications of Remote Sensing, and Geographic Information System (GIS), and geophysics and with the technology such as satellite and piezocone technology. The data acquired will help in establish baseline groundwater quality conditions, identify principal hydrogeologic units and develop a geologic model of the site, and model tailings impoundment development and estimate contaminants loadings. Geochemical characterization is also an important factor to be determined especially in dealing with the tailings that are potentially acid generating that cause acid rock drainage (ARD). Geochemical characterization with the data gathered in geotechnical issues enables new developments to reduce ARD potential tailings. These new developments include designing for chemical issues such as design for submergence by flooding the tailings at closure, treatment of tailings to create non-acid generating covers, and lake or ocean subaqueous disposal; and improves the basic design concepts in upstream construction, lined tailings impoundments, dewatering technologies, “dry” cake filtered tailings disposal, and in thickened and paste technologies. Instrumentation and monitoring are essential activities for the management of tailings facility in the duration of the industries up to its closure. This will check the environmental of the facility is meeting design intent, confirm that the dam and impoundment are safe throughout its intended lifespan, and provide data required for confirmation and optimization of design and construction through the successive stages of impoundment construction and development. In conclusion, environmental considerations have been the most significant concerns in tailings dam design and permitting and failure in meeting these standards will led to scrutiny of mining projects. Therefore, numerous guidelines and risk assessment programs have been developed by the industry to prevent these failure risks.