Hard-rock mining has had a long and often alarming history in the United States and around the world. Even modern mines built to meet stringent regulations and promising "zero" pollution have failed to deliver on those assurances.
Some of the worst have led to devastating pollution of fish-bearing streams and wildlife habitat and have required massive, hugely expensive long-term cleanup, typically at taxpayer expense.
Alaska has not been immune from environmental problems associated with hard-rock mining, a history that is not being ignored as planning progresses toward what may become the largest open-pit mine in North America the Pebble project near Iliamna being planned by Canada-based Northern Dynasty Minerals Ltd.
Alaskans for Responsible Mining, an Anchorage nonprofit organization pushing for tighter restrictions on mining in Alaska, provided examples of modern mines that government and industry predicted would have little or no impact on the environment.
Unfortunately, those predictions were wrong.
The Greens Creek Mine, located on Admiralty Island in Southeast Alaska, is a gold, silver, lead and zinc extraction operation run by Kennicott Minerals Co. and Hecla Mining Co. It went into full production mode in 1989.
During its permitting phase, no impacts from leaching metals or acid mine drainage were expected. However, the Alaska Department of Environmental Conservation documented acid mine drainage and contamination from leaching sulfate and heavy metals, and the mine had been cited for 391 violations of the Clean Water Act by 2003.
According to the Southeast Alaska Conservation Council, the operators' own consultants predict it may take 20 to 50 years for mine wastes to begin generating acid mine drainage. Water treatment may be necessary for "hundreds of years."
Red Dog Mine in the Brooks Range is the source of zinc and lead. When first proposed, officials said no contaminated water was expected to seep from mine operations. However, in 1989 mine construction may have caused increases in zinc contamination in local streams and the Wulik River.
The Environmental Protection Agency issued a penalty in 1991. The mine's operator, Teck Cominco, eventually spent $11 million rerouting Red Dog Creek to isolate the creek from the mine.
Until relatively recently, predicting levels of acid mine drainage was difficult.
"It used to be harder to predict," said Patty McGrath, mining coordinator for the EPA's Region 10 headquartered in Seattle. "Now there is a chemical test."
McGrath said public concern about mining's impact on the environment is well placed, but people most frequently hear about mines that have failed to contain their wastes. Despite its problems, Red Dog Mine is "generally operating successfully," from an environmental perspective, she said.
Another example of a relative environmental success story, McGrath said, is Thompson Creek Mine, a molybdenum source covering 2,500 acres near Stanley, Idaho, making it the state's largest mine. The potential for acid mine drainage was not considered by the U.S. Forest Service when permits were issued, but such damaging drainage developed in the tailings facility, nevertheless. The mine's $19 million bond isn't expected to cover long-term costs of water treatment or capping the tailings facility, according to the Idaho Conservation League.
"Every now and then they have problems," McGrath said of Red Dog and Thompson Creek. "But I wouldn't call either one a disaster."
However, disasters do occur.
The Gilt Edge Mine, a gold source near Deadwood, S.D., operated between 1988 and 1996. Acid drainage was not considered an issue when it was permitted. But acid drainage left local streams unable to support life. Its operator, Dakota Mining, declared bankruptcy, leading U.S. Sen. Tim Johnson, D-South Dakota, to lament "foreign corporations" that "left a mess" behind. That mess become an EPA Superfund cleanup site.
The Zortman-Landusky gold mine near the Fort Belnap Indian Reservation in central Montana ran from 1989 to 1998 when its operator, Pegasus Gold Inc., abandoned the site and filed for bankruptcy, leaving behind a $33 million cleanup tab.
Federal and state agencies had predicted no adverse impacts to water quality, yet by 1993 Pegasus was being sued by the state and the EPA. Montana officials have said water treatment will have to continue "forever."
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