The J.R. Simplot Co., the Idaho Department of Environmental Quality, the U.S. Environmental Protection Agency and the U.S. Department of Interior have signed an agreement to investigate selenium contamination at Simplot’s Conda mine site in Southeast Idaho. The work conducted at the Conda mine site under the Consent Order/Administrative Order on Consent (CO/AOC) is one of 14 site-specific investigations under way or that will be started in the next few years to address contamination in the Southeast Idaho phosphate mining area.
Doug Tanner, Pocatello waste and remediation manager with the IDEQ, the lead agency, said the agreement is the first step toward understanding the extent of selenium and other contamination at the 1,700-acre Conda site about eight miles north of Soda Springs in Caribou County. The Bureau of Land Management, U.S. Fish & Wildlife Service and the Shoshone-Bannock Tribes are participating as support agencies, but the U.S. Forest Service and Bureau of Indian Affairs have declined support agency status.
The site was mined for phosphate by various operators between 1906 and 1984, and included a town site and a mill in addition to underground and surface mining. It was the first Idaho mine to operate under a federal mining lease. Simplot acquired the mine in 1960. There now is no active mining at the site, and the Conda town site no longer exists, but Simplot operates a pump booster station at Conda for its 87-mile slurry pipeline between the Smoky Canyon Mine and Simplot’s phosphate fertilizer plant near Pocatello.
The agreement outlines how Simplot will investigate the site under state law and the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) with state and federal oversight.
Without admitting liability, Simplot has agreed to terms and conditions of the agreement without the issuance of a Notice of Violation or the holding of a compliance conference under applicable Idaho law. By signing the agreement, however, Simplot does not concede nor waive its right to object to the authority of the U.S. or IDEQ to issue, take or enforce any other order or action relating to the site.
The agreement requires Simplot to perform a remedial investigation/feasibility study to look for and assess contamination from mining and/or town site activities and evaluate any threats to human health and the environment. It also requires possible clean-up alternatives be identified and evaluated.
In preliminary investigations, Simplot’s voluntary samplings have detected selenium and other hazardous substances above background concentrations at the site. Subsequent samplings by IDEQ, BLM, the Idaho Mining Association and their contractors indicate these substances are being leached from waste rock at the site into the environment and may be impacting vegetation and surface water.
Simplot shall submit and implement Sampling and Analysis Plans that include a site health and safety plan, quality assurance project plan and field sampling plan.
The CO/AOC also calls for development of a community relations plan to determine community concerns, interests and involvement, and requires establishment of an information repository for public access to documents related to investigation activities.