Indicators And Discriminators Used To Separate Metal Sources From Contrasting Upstream Mining Districts

Mining has played an important role in the development of the western U.S. Mineral extraction and<br>production is a wealth creating endeavor that provides jobs and supplies raw materials needed to sustain an<br>industrial economy. Increased use of public lands resulting from a growing population has increased public<br>awareness of the effect of mining activities on the environment. Today, mining practices of many companies<br>are closely regulated to reduce these effects, but unfortunately, mining practices of the past have resulted in<br>substantially increased concentrations of many metals associated with sulfide ore deposits in both soils and<br>stream sediments. The U.S. Geological Survey has adapted geochemical and isotopic tracer methods,<br>originally developed for mineral-resource assessment, to delineate the extent of metal contamination from<br>mineral extraction and mineral processing in the environment. Our goal is to use these scientific methods to<br>define the extent of the area affected by mining and to advise the public and private industry on the<br>effectiveness of mitigation strategies. Application of these methods to drainage basins in the western U.S.,<br>where land-management and trust-resource agencies have particular concerns about the effects of mining<br>on human health and aquatic and riparian habitats has resulted in delineation of discrete areas affected by<br>mineral-resource extraction activities.