Regulators concede some water from PolyMet copper-nickel mine might reach Boundary Waters

Industrials Associated Press

Federal and state regulators have conceded that potentially polluted water from the proposed PolyMet copper-nickel mine could flow toward the Boundary Waters Canoe Area Wilderness instead of away from it, as intended.

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As a result, the U.S. Environmental Protection Agency has urged Minnesota officials to propose a solution in the final version of the environmental review of the project, which has been in the works for 10 years and is due out later this year, the Star Tribune reported Wednesday (http://strib.mn/1UrhjU8 ).

The problem, which was identified by scientists working for the Minnesota Chippewa Tribe, was first reported last month by the Timberjay, an Ely weekly newspaper.

Environmentalists and tribal officials say technical documents show the project's water flow model is badly flawed and understates the threat to the pristine BWCA.

"How, after 10 years of study, can we not know which way the water is going to go?" said Kathryn Hoffman, an attorney with the Minnesota Center for Environmental Advocacy. "It suggests that there is a lot we don't know about the impact."

The Minnesota Department of Natural Resources, which is leading the environmental review, said in a statement Tuesday that it is evaluating the scenario. It was only brought to its attention recently, the agency said.

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But PolyMet Corp. said it is confident that its water modeling is valid. It said in a statement that questions will be addressed by the lead regulators.

It was long assumed that water from PolyMet's planned mine would flow south toward the St. Louis River and Lake Superior, and away from the BWCA.

But the tribal scientists with the Great Lakes Indian Fish and Wildlife Commission pointed out in a June 18 letter to government agencies that groundwater flow in the area is strongly influenced by a 12-mile long iron mine just a mile north of PolyMet's proposed site — the Peter Mitchell pit owned by Northshore Mining Co. Recent operations in the Mitchell pit have removed a geological barrier that once stood between the two watersheds.

When the iron mine eventually closes, its water level will be 300 feet lower than the level in PolyMet's open pit at closure, according to the GLIFWC scientists. And water flows downhill.

In a June 22 memo, the DNR and federal officials disputed the tribal scientists' conclusions. They said they believe rain and other drainage sources will create an underground "groundwater mound" that would act as a barrier to any flow from the PolyMet site.

However, they conceded that a northward flow from the PolyMet site is a "theoretical possibility."

Technical documents reviewed by the Star Tribune outlined some actions, such as monitoring and groundwater extraction wells, that could mitigate a northward flow of groundwater. The EPA told the state such "adaptive management" strategies could be acceptable.

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Information from: Star Tribune, http://www.startribune.com