WASHINGTON— Kennecott Utah Copper Corporation (Kennecott), the second largest copper producer in the United States, has agreed to implement a comprehensive cleanup of groundwater contamination from past mining operations related to the Bingham Canyon Mine located southwest of Salt Lake City, the Justice Department and Environmental Protection Agency (EPA) announced today.
Kennecott has already begun cleanup at the site which is expected to cost $15 million and take over four decades to complete. Under the terms of the settlement, Kennecott will also pay over $5 million for costs associated with prior investigations and other actions by EPA at the site and surrounding areas.
The consent decree, which outlines various remedial cleanup that Kennecott has agreed to perform, was reached through the collaboration of the Justice Department, the EPA, and the State of Utah and was filed today in U.S. District Court for the District of Utah.
Kennecott operates the mammoth open pit “Bingham Canyon Mine” in the Oquirrh Mountains nearly 30 miles southwest of Salt Lake City, Utah. The Kennecott South Zone Site encompasses the historic Bingham Canyon mining district, surrounding areas, and areas impacted by releases or threatened releases of hazardous substances from mining operations in the area.
According to the settlement, Kennecott will finance and perform the groundwater cleanup, reimburse all federal and state oversight costs, and settle all past and future costs associated with the cleanup of groundwater contamination, described as Operable Unit 2 (OU 2) of the Kennecott South Zone site.
“Kennecott has agreed to remediate and monitor some areas of major contamination that were a detriment to the environment and people of Utah,” said Acting Assistant Attorney General Ronald J. Tenpas. “The company continues to work with the United States to address the contamination and cleanup at the site.”
“This settlement is an example of the environmental benefits that can be obtained when all of the parties work toward a common goal,” said Robert E. Roberts, EPA Regional Administrator in Denver.
The proposed consent decree requires Kennecott to meet three major objectives for the cleanup of OU 2 Zone A groundwater plume. The Zone A plume is the portion of the groundwater aquifer contaminated by acidic waste water that has leached from waste rock dumps and that has been contaminated by other wastewaters generated from operations in the mining district. The plume of contamination is about 20 square miles in size with a highly acidic core area of two-square-miles with high concentrations of sulfates and heavy metals.
The three objectives outlined in the settlement agreement include:
-Kennecott will reduce the OU 2 Zone A groundwater plume. To achieve this, Kennecott must extract groundwater from the core area of the plume until it meets a performance standard of 1,500 ppm for sulfate. After that, Kennecott will monitor conditions in the groundwater as contamination naturally attenuates to a final standard of 500 ppm for sulfate;
-Kennecott will prevent the Zone A plume from moving beyond certain compliance points through the use of groundwater extraction wells that intercept the leading edge of the plume; and
-Kennecott must prevent the recontamination of the Zone A plume by intercepting, containing and collecting for disposal all source area waters behind the Eastside Collection System and maintaining the system to prevent leaks.
The cleanup objectives agreed to in the consent decree were originally set forth in a record of decision issued by the EPA in 2000 with concurrence by the state of Utah, later modified and updated by the EPA in 2003 and 2006.
The consent decree was lodged in the U.S. District Court for the District of Utah and is subject to a 30-day public comment period. A copy of the consent decree will be available on the Department of Justice Web site at http://www.usdoj.gov/enrd/Consent_Decrees.html.