U.S. EPA conducts soil sampling and radiological survey work at Anaconda Mine site

SAN FRANCISCO -- The U.S. Environmental Protection Agency is conducting soil sampling and radiological assessment work at the Anaconda Mine site in Yerrington, Nev.

“The sampling we are doing now will build on our previous work here at Anaconda,” said James Sickles, the EPA’s Superfund remedial project manager for the Pacific Southwest region. “The goal of the work going on now is to identify any radiological hazards and continue with soil and groundwater monitoring.”

The EPA is using a drill rig to sample soil under existing heap leach ponds to determine what steps will be necessary to permanently close the ponds. Additionally work crews are conducting a thorough radiological survey in areas that were previously identified as showing elevated radiological readings. The radiological survey is using a sophisticated gamma radiation detector and hand held radiological survey equipment.

The agency is also overseeing two Atlantic Richfield Company work crews drilling deep monitoring wells and collecting soil samples around the former mine. The monitoring wells are being used to assess the extent of groundwater contamination. The soil samples will give the agency baseline levels of contamination.

Last spring, the EPA capped 100 acres of mine tailings to prevent erosion and dust blowing from the site. In late summer the agency constructed and lined 2 new heap leach evaporation ponds before the fall and winter rain season to prevent overflow of mine drainage. Work to date including current sampling work has run just over $2 million.

Originally known as the Empire Nevada Mine, the site began operation around 1918 and was acquired in 1953 by the Anaconda Minerals Company. From 1977 to 1982 the company was owned by Atlantic Richfield Company and then sold to Don Tibbals, a local resident, who subsequently sold his interests to Arimetco Inc., with the exception of the Weed Heights community.

Arimetco operated a copper recovery operation from existing ore heaps within the site from 1989 to November 1999. Arimetco has terminated operations at the site and is currently managed under the protection of the United States Bankruptcy Court in Tucson, Ariz.

The major threats on the site come from metals contaminating the groundwater and fugitive dust that could impact human health and surface water. Mining operations enhanced levels of naturally occurring uranium, making the radiological substance more pervasive and mobile in and around the site. Additional concerns include contaminated surface water that can impact wildlife.