Officials confident about Leviathan Mine cleanup | TahoeDailyTribune.com
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Officials confident about Leviathan Mine cleanup

A new treatment system is up and running at a highly polluted inactive Alpine County sulfur mine, and state water officials hope to have more work completed by the end of next year – enough so that no acidic, toxic water leaves the site.

“Hopefully, by next year we will be in a situation where there will be no untreated acid mine drainage leaving the site,” said Harold Singer, executive director of the Lahontan Regional Water Quality Control Board.

The Leviathan Mine has been polluted for decades, and the U.S. Environmental Protection Agency has indicated plans to propose it for listing on the Superfund National Priorities List. However, officials from Lahontan, which has owned the 7,000-foot-elevation mine since the early 1980s, think the state agency has a good handle on the cleanup.



EPA has indicated it would bring more of a long-term approach to the cleanup.

Singer agreed that is needed. However, the agency can’t ignore short-term problems either, he said.




“We’ve got to look at other measures. We have to look at reducing the amount of acid mine drainage being produced,” Singer said. “We also have to look at short-term priorities, too. We can’t wait five years for the fix.”

The Leviathan Mine, located 25 miles south of Gardnerville, was first mined in 1863. Comstock workers mined it for copper sulfate to process silver in Virginia City. The mine later became a dedicated copper mine, and it was used that way until 1869.

Those mining activities used adits, or mining tunnels, and did not harm the water quality of the region.

A mining business called Anaconda, Co. purchased it in the 1950s and used it as a sulfur mine. The company excavated hundreds of acres of land, creating an open pit mine – a type of operation known for causing water quality problems.

Water runoff going through the mining site mixes with sulfur. The sulfur lowers the water’s ph level, meaning it makes the water acidic. The acidic water then dissolves toxic metals in the ground: copper, iron, aluminum, nickel and – the most hazardous of the bunch – arsenic. The new solution is called acid mine drainage or, as Singer described it, “acidic metal-laden bad stuff.”

After Anaconda sold the site in 1963, Leviathan Creek flowed directly through the disturbed area. Acid mine drainage flowed into the creek; water in the creek itself became acid mine drainage. The stream flows into nearby Bryant Creek, and as recently as 20 years ago, contaminated water flowed from there into the East Fork of the Carson River.

Lahontan bought the mine in the 1980s, and since then Singer estimates the agency has taken care of 70 percent of the problem. Leviathan Creek was channeled with concrete where it runs directly through the site, keeping toxic water from hitting it. Concrete trenches were built through the area to catch clean water, keep it from being contaminated, and release it into the stream.

Additionally, runoff of the polluted water now, for the most part, is diverted into five evaporation ponds. Together, they hold 13 million gallons of the toxic water.

The problem is only 2 to 3 million gallons evaporate in a year, and when 6 to 8 million gallons are created each spring runoff there is major overflowing.

At a cost of $1 million, Lahontan this summer has built a University of California, Davis-designed treatment system which officials hope will create enough space in the ponds to avoid future overflows. Acid mine drainage is pumped out of the ponds, treated and the clean water is released back into Leviathan Creek.

That isn’t the only way contaminants are entering the creek, though. A “seep” that has existed since Lahontan’s initial work releases 20 gallons of acid mine drainage into the creek per minute. Additionally, a new seep started earlier in the 1990s – about the time of the Genoa earthquake. Officials don’t know how much polluted water has been released.

The state agency has built what is called a passive treatment system to stop the new seep. Designed by the University of Nevada, Reno, it acts as an artificial wetlands, lowering the ph of the water and filtering out the metals, which, when solid, are not toxic.

An identical system should be built next year to treat more acid mine drainage.

“The bottom line is: This year, no ponds overflowing; next year, no untreated acid mine drainage leaving the site,” Singer said.

The state of California has not taken a position on the Superfund listing, Singer said. However, if Leviathan is listed, Lahontan, by virtue of being the property owner, could be considered a potential responsible party. EPA could force ARCO – which now owns Anaconda – and possibly Lahontan to pay and implement the long-term cleanup, an action Lahontan believes it is currently doing.

“Putting it on the list doesn’t mean EPA is going to bring their trucks out here tomorrow and clean up the site,” Singer said.

After this summer, Lahontan likely will have spent about $7.5 million on cleanup of the Leviathan Mine.

“We are paying it right now. This whole issue of who is responsible and who will pay will probably be decided in the courts,” Singer said.


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