Leviathan mine ponds cleansed of toxic metals | TahoeDailyTribune.com

Leviathan mine ponds cleansed of toxic metals

by Jeff Munson

A first phase of cleanup at Leviathan Mine southwest of Gardnerville is being called a success by water quality officials, who said more than 10 million gallons of polluted water at the mine’s treatment ponds has been neutralized.

The pond water contained large amounts of heavy metals and arsenic.

The treatment process essentially neutralized the most acidic elements in the ponds, said Chris Stetler, chief of the Leviathan Mine unit for the Lahontan Regional Water Board.

“By eliminating the pond overflow, we have eliminated the most contaminated water that enters into the the latest phase of cleanup at the mine began last year when the board hired Unipure Environmental of Fullerton, Calif.

The company employs several people from the Gardnerville and Markleeville areas.

Lahontan chief executive officer Harold Singer said he’s pleased with the work that’s been done.

“With the skilled assistance of local community members … we were able to make great advances in the operation of our treatment system and reduce overall costs,” Singer said.

Leviathan Mine is an inactive sulfur mine that was listed as a Superfund site in May 2000.

Superfund status means the U.S. Environmental Protection Agency qualified Leviathan Mine as among the most contaminated sites in the country.

To treat the water, lime was added to neutralize the heavy metals. The process separates and neutralizes contaminants such as iron, aluminum, arsenic, nickel and copper.

Historically, the ponds have overflowed into Leviathan Creek, rendering it sterile and killing plant and aquatic life.

However, in 1998 the board ordered the ponds to be cleaned and lowered.

Water has not overflowed into Leviathan Creek since 1998.

In addition to water treatment, the Lahontan board has ordered certain measures at the site.

One is to implement a monitoring program that includes monthly water quality samples and continuous flow to study facility equipment.

California acquired Leviathan Mine in 1984 to clean up water quality problems caused by open-pit mining.

The biggest problem has been sulfuric acid discharge into Leviathan and Aspen Creeks, which empty into the east fork of the Carson River.

While the discharge was not hazardous to humans, it did pose a threat to fish and wildlife down stream, Stetler said.

Seeing the potential for down stream problems, the board decided to clean the worst part of the site first.

“We treated all of the pond water that was there from the time the ponds were built. It was the most concentrated, most acidic on the site,” he said. “We’re glad to have this stuff behind us now.”

Work at Leviathan Mine will resume next spring. The two-year contract with Unipure Environmental is for $650,000 annually.

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