Leviathan Mine pollution will flow, but not as much
Despite efforts by the state of California last summer, acidic water polluted with toxic metals probably will overflow from five retention ponds at the Leviathan Mine this spring, continuing pollution of creeks that flow into the Carson River.
While it’s possible millions of gallons of polluted water could pour into Leviathan Creek, the amount likely will pale in comparison to past years when little or no work was done to stop the overflow.
“It should be about 5 million gallons less than it would be if they hadn’t done anything up there, and that’s a good thing,” said Kevin Mayer, Superfund project manager for the U.S. Environmental Protection Agency. “I think we’re really learning what it’s going to take to stop the ponds from overflowing in a typical year. We – ARCO, the (Lahontan) regional board and EPA – are starting to realize what we need to accomplish to prevent acid mine drainage from getting into the creek.”
Twenty-five miles south of Gardnerville, six miles east of Markleeville and described as a giant white scar in the mountains of Alpine County, the Leviathan Mine is an inactive sulfur mine now contaminating nearby Leviathan Creek with acid mine drainage – acidic water containing dissolved toxic metals such as iron, copper, aluminum, nickel and arsenic.
Leviathan Creek, which has been discolored and cannot support aquatic life, runs into Bryant Creek, a tributary of the East Fork of the Carson River.
The Lahontan Regional Water Quality Control Board bought the mine in the 1980s, and state officials estimate it has taken care of 70 percent of the problem. Runoff of the polluted water now is diverted into five evaporation ponds. Together, they hold about 16 million gallons of toxic water. Historically, however, there have been problems because only a few million gallons evaporate in a year. When 6 or more million gallons are created each spring runoff, there has been major overflowing.
Lahontan officials last summer built a $1 million system for treating the contaminated pond water in order to create capacity for more runoff. From the ponds, the system pulled out the acid mine drainage, took out the acidity and toxic metals, and returned the cleaned water into Leviathan Creek.
EPA and ARCO – which purchased the one-time owner of the mine, Anaconda Co., that was responsible for the contamination – attempted to build similar systems the two previous years without success.
Lahontan treated about 4.5 million gallons of polluted water water in 1999, and nearly that amount evaporated, leaving 9 million gallons of capacity to catch runoff in the winter and spring of this year.
The problem now, however, is that only about 2.7 million gallons of capacity remain, leading officials to believe overflow again is probable.
“It’s not a done deal that they will overflow,” Mayer said. “We may get an early summer. We might just get lucky. But I think it is probably on the extreme edge of optimism that there won’t be any overflow.”
At the beginning of the winter in 1998, the ponds had 3 million gallons of storage capacity. Between January and June of 1999, however, 8.8 million gallons overflowed.
Lahontan wasn’t able to get the system operating until late August last year, and because of the weather at the 7,000-foot-elevation mine, officials had to stop work in October. Mayer said plans this year are to get the system running earlier.
“We need to get probably 12 million gallons of capacity, ideally even more, for the ponds to not overflow next year,” Mayer said.
EPA last year proposed to list the mine as a federal Superfund site. The Washoe Tribe of Nevada and California, Alpine County, Douglas County and the Carson City-based Carson Water Subconservancy District, which are concerned about the quality of water in the Carson River, support the listing.
Mayer said the listing could become official as early as April. Superfund status would provide money and resources for cleanup, but also mark the 250-acre site as one of the most polluted places in the country.
The overflowing ponds are not the only sources of contamination to the creek; underground seeps also put pollutants into the water. Officials don’t know exactly how much pollution is coming out of the Leviathan Mine, and they don’t know if the acid mine drainage is having a detrimental effect on the Carson River.
“The ponds, as we’ve known, are really just part of the problem,” Mayer said. “We need to get a more complete understanding of what’s going on.”
The Leviathan Mine, which has been closed for nearly 40 years, was first mined in 1863 for copper sulfate to process silver in Virginia City.
Early mining activities did not harm the water quality of the region. However, a mining business called Anaconda Co. purchased it in the 1950s and used it as a sulfur mine. Anaconda constructed an open-pit mine, a type of operation known for causing water quality problems.
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