Extraction procedure testing of solid wastes generated at selected metal ore mines and mills

Solid waste samples from a reconnaissance study conducted at ore mining and milling sites were subjected to the U.S. Environmental Protection Agency extraction procedure (EP) leaching test Sites visited included mines and mills extracting ores of antimony (Sb), mercury (Hg), vanadium (V), tungsten (W), and nickel (Ni). Samples analyzed included mine wastes, treatment pond solids, tailings, low grade ore, and other solid wastes generated at these facilities Analysis of the leachate from these tests indicates that none of the samples generated leachate in which the concentration of any toxic metal parameter exceeded EPA criteria levels for those metals. By volume, tailings generally constitute the largest amount of solid wastes generated, but these data indicate that with proper management and monitoring, current EPA criteria can be met for tailings and for most solid wastes associated with mining and milling of these metal ores. Long-term studies are needed to determine if leachate characteristics change with time and to assist in development of closure plans and post closure monitoring programs.