Treatment at Leviathan Mine keeps toxins from reaching creek

The Lahontan Regional Water Quality Control Board reports that emergency treatment of acid mine drainage stored in ponds at the Leviathan Mine Superfund site in Alpine County has successfully prevented discharge of approximately 3 million gallons of untreated toxic water to Leviathan Creek, a tributary of the East Fork of the Carson River.

As a result of the highest amount of rain and snowfall since 1995, acid mine drainage from ponds at Leviathan Mine threatened to overflow in April. Through May 15, precipitation near the site was at 155 percent of average, or 11 inches above normal. The Water Board’s contractor began operating an emergency treatment system on April 5. The treatment system neutralizes the AMD stored in the ponds by mixing the contaminated water with lime.

Toxic metals from the AMD are captured as sludge on the pond bottom, and treated water is discharged to Leviathan Creek. The discharged water meets water quality criteria established by the U.S. Environmental Protection Agency. The emergency treatment operation is being conducted under approval from the EPA, which has jurisdiction over operations at this Superfund site.

Leviathan Mine is an abandoned sulfur mine five miles east of Markleeville and six miles west of Topaz Lake, Nevada. California acquired the mine in 1984 to clean up water quality problems caused by historical mining. The Water Board completed a pollution abatement project at the mine in 1985, and since 1999 has continued to actively treat waters discharged from the mine site.