Here’s a story from the other side of the country about a used-up sulfide mine. When an acid mine is retired, often its work on the environment has only begun.

Shuttered mines still spewing poisons
Costs soar as acidic waters gush freely from 12 of Oregon’s abandoned mines

By Diane Dietz
The Register-Guard

The federal government has formally proposed adding the polluted and abandoned Formosa mine in Douglas County to the Superfund list of the nation’s worst toxic waste sites.

The move eventually could lead to a federal cleanup of the shuttered copper mine about 25 miles south of Roseburg, said Ken Marcy, U.S. Environmental Protection Agency coordinator for the Superfund list in the region. A listing also could spark an intensified federal effort to get those responsible to pay for the cleanup, Marcy said.

The Formosa mine, perhaps the most polluted mining site in the state, was actively worked by a Canadian venture, Formosa Exploration Inc., from 1990 to 1993. Formosa was partly funded by two Japanese firms.

The state shut down the operation after Formosa repeatedly violated its state permit by excavating more than allowed and spreading waste rock over the 76-acre site atop Silver Butte. Within the honeycomb of mine shafts in the mountain, sulfide-bearing rock is exposed to air and water, creating an acidic, metals-contaminated brew that pours out of the mine entrance and from fissures in the mountainside. The mine spews about 5 million gallons a year of the acidic water into nearby streams. The effluent has killed about 18 miles of salmon-rearing tributaries to the South Umpqua River, including part of Cow Creek.

The mine poses a “serious, ongoing threat” to people and the environment, the EPA said.

The site has contaminated fish in Cow Creek, which is fished by members of an Indian tribe and by recreational fishermen, the agency said.

Read the rest of Mine may make Superfund list in the Eugene Register-Guard and/or visit the Umpqua Watersheds page of the Formosa (Silver Butte) Mine.