Leviathan Mine cleanup progressing | TahoeDailyTribune.com

Leviathan Mine cleanup progressing

Nancy Dallas, Tribune News Service

Federal cleanup activities at an inactive open pit sulfur mine are just the beginning of a long-range plan to permanently rid nearby streams and the Carson River of toxic water pollution.

U.S. Environmental Protection Agency representative Kevin Mayer told members of the Carson Water Subconservancy District that it will be years before a long-term planned solution is in place for the Leviathan Mine, located in Alpine County approximately six miles east of Markleeville.

“This site is probably as good as you are going to get as far as doing things that obviously need to be done while you are still trying to understand how you can implement something that will deal with the problem over the long term,” Mayer said of the past summer’s activities. “As far as someday walking away from this (as with toxic waste landfills), we are not going to be able to take the Leviathan Mine and place it in waterproof baggies and ship it away.”

Mayer said the long-term goal is to take steps to minimize the amount of acidic drainage that is being produced by rain and snow melt percolating through the sulfur-contaminated soils at the site, capturing the remaining water and running it through a low-maintenance treatment system that will remove the threat.

“We are doing our best to do stuff now, but it is going to take years before that stuff is done and the remedy is in place.”

He noted that the nature of the threat, and the many uncontrollable factors, made it a difficult problem to control and eventually resolve.

When Anaconda purchased the mine in 1951 they extracted the sulfur by open-pit mining, generating tens of millions of cubic yards of mine waste. They took no effective measures to stop the resulting pollution before discontinuing operations in 1962. Ensuing owners did not have the financial means to prevent the pollution problems from increasing over the years.

After years of seeing no action being taken to correct the problems, the Carson Water Subconservancy District about two years ago began pushing to have the mine named a federal Superfund site. The EPA placed it on the National Priorities List, reserved for the nation’s most hazardous sites, in May 2001. The designation allows the cleanup effort to benefit from resources that would not otherwise be available, including the assistance of Arco, the potentially liable party, and the state of California, which has acquired the property to reduce the pollution.

Subconservancy board member Jacques Etchegoyen complimented the efforts of the EPA, noting that before it became a Superfund site, California had relieved Arco of any responsibility at the site.

“If this was not a Superfund site, Arco might not be involved. We are making a heck of a lot more progress than we were a few years ago. We are heading in the right direction.”

This past summer a lime neutralization method was used to successfully treat all 4 million gallons of highly contaminated water that was stored in 12 acres of evaporation ponds. In addition, approximately 1 million gallons of unconcentrated mine drainage was treated. The results gave indications the same system could be used for future treatment of ongoing mine drainage.

Arco succeeded in treating nearly 1.5 million gallons of contaminated acid drainage during two months this past summer. The cleaner water resulted in mine waste sediment appearing to have diminished and trout being observed in a creek immediately downstream from Leviathan Creek.

Mayer said next summer Arco would be working on turning their process into a full-scale treatment system. Once the most urgent water quality issues are addressed, increased attention will be focused on revegetating the entire 250-acre mine site.

Mayer said the EPA would rely on national and local expertise and input in addressing issues for the final plan to be developed over the next several years.

“There are a lot of things we need to do before we bring this plan forward for public review and before implementation,” Mayer told the board.

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