A proposed mining project in Boise County, Idaho for the extraction of copper, molybdenum, and silver deposits, required investigations into a possible tailings dam construction that will be built using the processed material from the mine. The mine is located southwest of Lowman Idaho, northeast of Pioneerville Idaho, and directly north of Jackson Peak Mountain. The total area for the proposed project is approximately 12 square kilometers and the estimated material to be excavated is about 1.99 billion cubic meters (BCM) (USDA 2013). Typical investigations into the construction of a tailings dam consist of identifying the types of ore contained within the mine, identifying a suitable location for the dam based on topography, and conducting an analysis of the geotechnical aspects of constructing the dam. In this project, construction of the tailings dam will adequately model a cut and fill operation where the excavated waste material will be used to construct the tailings dam. Construction of the tailings dam will happen in stages, with a starter dam followed by successive additions to accommodate the need for reservoir capacity. Several aspects such as excavation depth, the types of excavated soil and rock, the ore processing methods, and mechanical properties of the waste material, have been considered for properly conducting an analysis of the tailings dam. Also, aspects including the slope stability of the tailings dam, seepage velocities through the tailings dam, and slope stability after a seismic event have also be studied. This paper discusses the geotechnical aspects of the tailings dam construction including the stability of the dam under both hydrological and seismic conditions.
This document was originally published in Association of State Dam Safety Officials Annual Conference (Dam Safety 2017) by Association of State Dam Safety Officials. Copyright restrictions may apply.
Robbins, Thomas and Chittoori, Bhaskar C.S. (2017). "Geotechnical Evaluations of a Tailings Dam for Use by a Molybdenum and Copper Mine Project in Southern Idaho". Association of State Dam Safety Officials Annual Conference (Dam Safety 2017).