Atlantic Richfield to Pay $8 M for Leviathan Mine Cleanup

In a U.S. Environmental Protection Agency settlement announced on Jan. 21, the Atlantic Richfield Company (ARC) agreed to treat acid mine drainage and resolve other liabilities at a cost of more than $8 million at the Leviathan Mine Superfund Site in Alpine County, Calif., near the California-Nevada border.

Under the settlement, ARC will treat acid mine drainage for five years at a cost the EPA estimates at $5.6 million. In addition, the company will reimburse EPA for $1.7 million in past clean-up costs, pay $90,000 in penalties for failing to comply with an EPA order issued in 2000, and spend $400,000 on a riparian restoration project at the River Fork Ranch on the Carson River, near Genoa, Nev.

"Today's agreement addresses the most significant pollution from the mine and protects Leviathan Creek until a long-term cleanup strategy is in place," said Keith Takata, the Superfund Division director the EPA's Pacific Southwest region. "This settlement makes sure that the company that caused the pollution pays for the cleanup and restores vital habitat downstream from the site."

Until a final plan is developed, seasonal treatment will prevent untreated releases of elevated concentrations of metals and metalloids, most notably arsenic, as well as iron, aluminum, chromium, cobalt, copper, nickel, and zinc. There are several releases of acid mine drainage at the site that have the potential to impact Leviathan Creek. When a release from the site occurs, it can flow into the Leviathan Creek/Bryant Creek watershed, which drains into the East Fork of the Carson River -- a major source of water and a habitat for fish.

Under EPA oversight, the company will treat acid mine drainage from several sources at the mine from June 1 to September 30. The treatment season will be extended before the final cleanup is selected, if conditions at this remote mountain site allow safe access and operation. Because the site lacks paved roads and power lines, winter treatment of most seeps will not be accomplished through interim actions, although cutting-edge biological treatment technology will continue to treat one of the seeps at the site through the winter.

Today's settlement complements a separate EPA order issued in June 2008 requiring ARC to investigate long-term cleanup methods for the site, which the EPA will select. Afterwards, the agency anticipates that ARC, the state of California, the Washoe Tribe of Nevada and California, and other stakeholders will enter into negotiations to implement final cleanup by 2013 and address other outstanding issues at the site.

The settlement also resolves the EPA's claims that ARC violated a 2000 order when it released untreated acid mine drainage for nine days in the summer of 2006 and failed to build a year-round treatment system that the EPA had required for treatability studies. The EPA subsequently decided to proceed with seasonal interim treatment for most of the site, while the investigation for long-term cleanup explores options for year-round treatment.