Response to Selenium Contamination at Phosphate Mines in Southeastern Idaho

Abstract

Selenium contaminated vegetation and surface water related to phosphate overburden disposal was discovered in southeast Idaho in 1997. Shortly afterward, phosphate mining companies and regulatory agencies joined in response to the potentially widespread problem throughout the phosphate mining area. Mining companies with a vested interest in Southeastern Idaho phosphate reserves organized as a committee under the Idaho Mining Association. Under this arrangement, they commissioned a regional environmental sampling program to characterize the problem in voluntary collaboration with Federal and State regulatory agencies. In 2000, the agencies in cooperation with tribal authorities agreed to coordinate their regulatory responses under a Memorandum of Understanding (MOU) that identified statutory and regulatory authorities and responsibilities; established priorities, and clarified processes for undertaking area-wide and site-specific investigations. Within the agreement, participating agencies and the Shoshone-Bannock Tribes set out frameworks for response actions and regulatory cost recovery. This group of agencies and the Tribes entered into an enforceable Area-wide Administrative Order of Consent (AOC) with the mining companies to conduct area-wide site investigations and risk assessments intended to lead to the development of remedial action objectives, remediation goals, and risk-based cleanup levels for selenium and other contaminants of concern. The U.S. Forest Service and Idaho Department of Environmental Quality, with support from other State, Federal and tribal authorities are cooperating to plan localized site investigations and engineering evaluations/cost analyses at individual mines. Data collected during the course of site-specific and area-wide efforts will eventually result in appropriate remediation of the selenium impacts at all developed phosphate mines in southeast Idaho. The authors describe the inter-agency and industry cooperative efforts in response to the selenium issue, highlighting the complications, successes, and stumbling points encountered along the way.

Jones, J., and B.W. Buck, 2004. Mine Design, Operations & Closure Conference, Polson, Montana, Mine Waste Technology Program, Montana Tech - University of Montana, Butte, Montana.