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Two years after the much-litigated PolyMet permits were issued, some facts aren’t in dispute

Minnesotans have learned a great deal about what PolyMet has proposed, very little of it good.

PolyMet Mining hopes to build one of the state’s first copper-nickel mine.
MinnPost photo by Walker Orenstein
PolyMet Mining building
Two years ago Sunday, on the eve of the last big election in Minnesota, the Department of Natural Resources (DNR) issued permits to PolyMet Mining to build and operate the first ever sulfide mine in the State of Minnesota — the most controversial decision the agency has ever made. In the two years since, those permits have been mired in litigation. In January of this year, the Minnesota Court of Appeals overturned the DNR permits and ordered DNR to convene a “contested case hearing” where a neutral administrative law judge could make findings on key issues on the basis of sworn expert testimony. Minnesota’s Supreme Court is reviewing that order now.

Much has been revealed about DNR’s decision making in these cases, and it’s not pretty. The Supreme Court seemed aware of one particularly questionable element of the PolyMet permits at last month’s oral argument. One of the justices questioned DNR’s lawyer about support in the record for PolyMet’s proposed method to minimize highly toxic “acid mine drainage” in the tailings basin. The “bentonite amendment,” as it’s called, would involve putting bentonite clay (mixed with tailings) on the dam, pond floor, and interior beaches of the basin as a sort of “cap,” in an effort to prevent oxygen from interacting with the tailings and producing acid. The scheme is absolutely central to PolyMet’s claim that it could control the nastiest form of pollution that sulfide mines are known to produce.

An experimental scheme

The court’s questions on the bentonite method, however, revealed just how little science there is in DNR’s record to support it. In fact, after the hearing, DNR asked the Supreme Court for permission to add documents to the permitting record to bolster its bentonite claims — a highly unusual move at this point in the process. But even those documents only further expose the experimental nature of the bentonite scheme. They establish that DNR does not know how the tailings and bentonite would be mixed, or applied, or whether the material would degrade over time. And they make clear the method has never actually been successfully demonstrated — let alone used — in the field.

In other words, essentially no one, including the DNR, knows if this bentonite idea would work.

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This is just one dimension of many in a complex case. As the court wrestles with questions like this, it’s useful to also take a step back and remind ourselves of the facts that are not actually disputed by any party to the litigation, and what those facts would mean for Minnesota. What follows are facts drawn directly from the permits that DNR issued — a sort of “best case scenario” if one were to accept all of PolyMet’s claims and promises as true.

A loss of almost 1,000 acres of wetlands

Building a PolyMet mine would require the direct destruction of almost 1,000 acres of wetlands — the largest permitted destruction of wetlands in Minnesota’s history. These wetlands take millennia to form, are a critical source of carbon sequestration, and once they are gone, they are gone. Peatlands cover only 3% of the world’s land, but store fully one-third of all soil carbon.

JT Haines
JT Haines
To operate the mine, PolyMet would use up to 6 billion gallons of Minnesota’s clean water every year to process the low-grade sulfide ore, resulting in water contaminated with sulfate, mercury, heavy metals, and potentially acids. This polluted water would be stored in a 900-acre pond, which would need to be maintained continuously by pumps, and held back, indefinitely, by a dam taller than the dome at the Minnesota Capitol.

The dam holding back the massive amounts of pollution and waste would be made from mine tailings stacked on top of other mine tailings stacked on top of unstable peats and slimes — the “upstream” design. This is the type of dam that failed catastrophically at Brumadinho in Brazil and at Mount Polley in Canada. It’s the type of dam that has been banned in countries around the world, including Brazil, Chile and Peru. And engineers have been clear they fear more catastrophes await if this design continues to be used.

Pond and dam: with us essentially forever

And because the permits issued by DNR would allow PolyMet to leave this all in place even after closing the mine (a “wet closure”), the pond and dam would be with us essentially forever. Even if everything were to work as promised, the company and DNR admit that it would still leak at least 16 million gallons of pollution into the groundwater, wetlands and rivers every year that the polluted pond exists.

So, there, behind the risky dam, the polluted water and mine waste would sit — 250 feet in the air, built on a pile of sand, with forever pumps, and a forever dam, leaking 16 million gallons of pollution into the Lake Superior Watershed every year. A quarter million northeastern Minnesotans, including in Duluth, Cloquet, and at Fond du Lac, would be living downstream of this threat in perpetuity.

What’s next?

In the two years since permits were issued by DNR, Minnesotans have learned a great deal about what PolyMet has proposed, very little of it good. And in the coming months the Minnesota Supreme Court will issue its ruling. If it joins the Court of Appeals in rejecting the permits, the Walz administration will have its own opportunity to do the right thing. That means rejecting the risky dam, rejecting the permanent pollution, and finally holding the neutral court hearing with experts from all sides that Minnesotans have been requesting for years. In other words, 2021 will bring with it opportunities for Minnesota’s leaders to act with more care and transparency in the face of a mining company that wants permission to leave behind a toxic lake upstream of our people, forever.

JT Haines is the Minnesota Center for Environmental Advocacy’s Northern Minnesota Advocate and is based in Duluth.

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