U.S. Water News Online
HELENA, Mont. -- A two-year project to move trainloads of accumulated toxic mud from a dam and haul it 90 miles for disposal is set to begin soon.
The work is a major step toward the 2008 removal of the century-old Milltown Dam on the Clark Fork River near Missoula. Arsenic and copper are among the contaminants in the mud tainted as historic mining in the Butte area sent pollution 120 miles down the Clark Fork, to its confluence with the Blackfoot River at Milltown.
Benefits of removing the mud and the dam include pollution control and enhanced fish passage, the U.S. Environmental Protection Agency has said.
Atlantic Richfield Co. acquired responsibility for pollution by the old Anaconda Co., for years Montana's mining giant, and is to cover most of the projected $100 million outlay for removing the dam and the mud, and related work.
A contractor estimates removing about 2.2 million cubic yards of mud from Milltown -- only about one-third of the total accumulation -- and transporting it for disposal will take roughly two years if the train operates seven days a week. The EPA's project manager, Russ Forba, said the mud being removed is the most contaminated. The rest can remain in place safely and stands to erode naturally over the years, Forba said.
Mud hauled by train will then be trucked briefly to a disposal site known as Opportunity Ponds, near the town of Anaconda. The actual ponds that the Anaconda Co. used for mine waste during much of the 20th century no longer exist. Now the place is classified as a waste repository, part of the Superfund program of environmental cleanup.
Some of the people with homes in nearby Opportunity, which has about 280 households, are apprehensive about the mud disposal.
"It's just more pollution on top of bad pollution," Maureen Holbrook of the Opportunity Citizens Protection Association said.
"I'm very unclear about why it's being removed from Milltown, and then it takes this 100-mile, magic carpet ride to Opportunity, Montana, and turns into negative vegetation."
Hammer said the mud is not expected to pose a risk at Opportunity because it will move from a water environment to a dry environment. When deprived of oxygen in a river, arsenic can move easily into groundwater, but that will not be an issue at Opportunity, EPA spokeswoman Diana Hammer said. Copper endangers fish, but in the quantities found in the mud, it will not jeopardize human health, she said.
Elevated arsenic levels have been found near Opportunity, but tests on water from domestic wells in Opportunity have not revealed arsenic at levels unsafe for humans, said Joe Griffin of the Montana Department of Environmental Quality. The groundwater does not flow in a way that would cause arsenic at the ponds to reach domestic water supplies, Griffin said.
Holbrook said plans to use uncovered railcars also have raised concern. People worry some of the mud in the cars will blow away during transit, she said. Hammer said it will be too moist for that to happen, but the situation will be monitored nonetheless.
People at Opportunity have complained about dust blowing off the Opportunity Ponds, and using the mud as a covering should address that concern, Hammer said.
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