USGS Home
Contact USGS
Search USGS

Process Studies of Contaminants Associated with Mineral Deposits

Project Objectives

This project focuses on identification of processes that result in significant environmental effects as a result of historical mining activities. These weathering processes are the natural reaction of sulfide minerals as they react with water and their effects on the aquatic and eolian environments surrounding historical mining districts. We focus our science on the understanding of these processes so that cost-effective and sensible remediation options can be developed by industry and the federal and state land-management agencies.

The objectives of the integrated Environmental Geochemistry projects are 1) to advance our understanding of the physical and biogeochemical processes responsible for the mobilization, transport, reaction and fate of environmentally significant elements (e.g., Al, As, Cd, Cu, Fe, Hg, Mo, Pb, Sb, Se, Zn) in mineralized near-surface systems and 2) to develop conceptual and quantitative models that link these processes to element distributions and concentrations. This knowledge provides the basis for sound scientific decision making, strategy development, and mitigation activities by local, state, and other federal agencies charged with minimizing the impacts of toxic elements on the environment and biota.

Project objectives include fundamental studies of the nature and scope of the effect of acid mine drainage (AMD) on the nation's waters, the evaluation of the acid-sulfate mineral deposit type on waters across different climatic zones, and the evaluation of ground-water flow paths in the Animas River watershed on water quality. Identification of specific flow paths from inactive mine sites to the surface streams has been an intractable problem that we hope to address through the development of a holistic GIS model of geologic domains within the watershed. Field tests of the model will be developed and implemented to test flow-path hypotheses. Evaluation of the recovery curve for aquatic life in watersheds following remediation will be developed to assist the Federal Land Management Agencies (FLMA) with projections of successful remediation within watersheds on Federal lands. More site-specific studies of processes on and within mine waste dumps and mill tailings are focused on evaluation of processes that result in movement of acid and toxic metals and metalloids away from mine sites into the receiving streams.

A summary of work can be found in the project fact sheet, Understanding Contaminants Associated with Mineral Deposits.

Relevance & Impact

Development of an overall strategy to deal with the large-scale problem of contamination of surface waters by inactive historical mines is imperative if the Federal Land Management Agencies are to develop a cost-effective approach toward its financial liabilities caused by historical mining on Federal lands. Engaging the National Park Service (NPS), Bureau of Land Management (BLM), and U.S. Forest Service (USFS) in discussions that focus on planning for future directions and evaluation of the scope of the AMD problem in the U.S. is necessary. This project is aimed at understanding the scope, mechanisms, and realistic solutions to these difficult and very costly issues.