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PolyMet’s Proposed NorthMet Mine

PolyMet Mining’s proposal to dig the first open-pit copper-nickel mine in northeastern Minnesota’s fabled canoe country has generated enormous concern. Thousands of citizens and organizations, including The Nature Conservancy, recently filed comments in response to the supplemental draft environmental impact statement (EIS) for the project.

In particular, the Conservancy expressed concern that the draft EIS shortchanges biodiversity, requires insufficient wetland mitigation, doesn’t adequately protect wild rice, doesn’t account for the combined impacts of mining and climate change, and postpones important decisions about financial assurance.

PolyMet’s NorthMet Mine would be located in the headwaters of the St. Louis River, a wild, forested country of high biodiversity significance known as the Sand Lake/Seven Beavers landscape, where the Conservancy owns nearly 7,000 acres. Mine pits would take the place of nearly 1,000 acres of forest, mostly lowland conifers, that would be lost to the project. Several thousand more acres would be sacrificed for waste rock stockpiles, roads, and other mining features.

Iron and taconite miners have dug huge open pits in Minnesota for more than a century. But this mine will be different: The copper-nickel ore, unlike iron ore, is locked in a formation that oxidizes on exposure to air and creates acidic drainage that may continue to seep into groundwater and surface water long after the mine is closed.

The Conservancy is concerned that the PolyMet proposal will diminish the biodiversity of the area and says the draft EIS “does not adequately evaluate significant environmental concerns that would be created by the development of the proposed NorthMet mine.” Says Doug Shaw, assistant state director of the Conservancy in Minnesota, “This is really important habitat including lowland conifer forest and all the rare native plants and animals that depend on it,” such as pine marten, lynx, wolves, and the state’s struggling moose population.

The Conservancy’s 80 pages of comments on the EIS highlight a variety of issues. But many of the organization’s most serious concerns fall into these five areas.

Land Exchange
The mine site lies on federal land in Superior National Forest. To mine, PolyMet must trade private land for 6,650 acres of federal forest land. PolyMet has proposed acquiring and swapping 6,723 acres of private land. But when the Conservancy evaluated the trade on the biodiversity and ecological value of the lands involved, conservation came up short. “This is not an equal exchange if you factor in the ecological value of these sites,” says Shaw. “We’re losing high biodiversity, high ecological-value sites in exchange for sites of lower quality and lower value.” As a result, the Conservancy says the land exchange, in its current form, isn’t in the public interest and provides recommendations for improving the ecological value of the exchange.

Wetlands and Mitigation
The Sand Lake/Seven Beavers’ lowland forest is rich in northern bird life and harbors many rare plants. The sponge like peat regulates water flow into nearby streams, reducing erosion and protecting water quality. “One thing to know about these kinds of wetlands is that they are very difficult to replace,” says Shaw.

The St. Louis watershed has already lost nearly 15 percent of its wetlands. PolyMet has proposed most of its wetland mitigation outside the St. Louis River basin.

As a result of these concerns, the Conservancy has proposed that PolyMet provide mitigation on at least two acres for every acre of wetland disturbed. And most, if not all, of the mitigation should occur in the St. Louis River headwaters to maintain the hydrologic and ecological functions those wetlands provide.

Wild Rice
Among aquatic communities, a particular concern is wild rice, once common in the region and vital to waterfowl and other wildlife. It has also been a historic staple of the local Ojibwe. Wild rice is vulnerable to high sulfide levels, a concern with mining, and rapidly fluctuating water levels.

The Conservancy has recommended that state sulfide standards apply not only to water in existing wild rice areas, but also in former and potential wild rice areas. Says Shaw, “Where there is potential for restoring wild rice, given its historical extent, those sites ought to be considered just like existing healthy stands of wild rice.”

Cumulative Effects
NorthMet isn’t the only mine in the pipeline. Also in preparation are proposals for mines in several nearby deposits. The Conservancy believes a mine-by-mine approach to environmental assessment is inadequate unless the cumulative effects of all the mines that are likely in the region are considered, especially given the long duration of impacts expected from these projects. The present draft EIS falls short, says the Conservancy.  What is needed is the kind of regional assessment of risks from mining that was recently completed by the U.S. Environmental Protection Agency in Bristol Bay, Alaska, (download 3.5 MB PDF), where large-scale copper and gold mining poses threats to salmon-dominated fisheries and the economies that depend on them.  The Conservancy believes a similar approach is needed here in Minnesota and can be done in advance of additional mine development.

Climate change is another cumulative effect. “It’s another factor that is stressing the waters and the habitats in the same way that mining will, exacerbating the effects,” says Shaw. This is especially true of certain kinds of habitats, like lowland conifer forests that are considered highly vulnerable to climate change. Says Shaw, “We think that there is some good science that they could draw on to evaluate this.”

Financial Assurance
Because leachate is likely to seep from the mine pits, waste rock stockpiles, and tailings basin for decades and possibly centuries, PolyMet has proposed water treatment long after the mine is closed. But who’s going to pay for it? By then, PolyMet may no longer be in business.

Minnesota requires “financial assurance” before mining begins, but copper-nickel mining is an unusual case because financial resources might need to last a century or more. Says Shaw, “A durable financial vehicle is going to be needed—something that will survive changes in government or agencies, certainly changes in company ownership.”

A detailed financial assurance plan has not been a part of the EIS process. The Conservancy thinks it should be. Why? Because financial resources are as integral to protecting the environment as physical precautions. “It’s a really important piece of the assessment of public risk,” says Shaw. “No one should be satisfied with what we’ve seen so far. So put some more meat to it and then open it up for additional public input.”

Furthermore, he says, the draft EIS is written from the perspective that assumes that everything will go as planned. “What if things go wrong?” asks Shaw, who wants the EIS to be modified to take contingencies into account.

Because the PolyMet proposal is likely to be the first of several copper-nickel mining proposals for northeastern Minnesota, it’s important to get the environmental review process right, he says. “Our position is because of the importance of this project—from biodiversity to cumulative effects to financial assurance—we’ve got to do this right.”

Download a copy (PDF 2mb) of The Nature Conservancy’s comments.

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