Serving Northern St. Louis County, Minnesota

Groups seek DNR stay on PolyMet dam permit

Request comes in wake of latest deadly tailings dam collapse in Brazil

Marshall Helmberger
Posted 2/10/19

REGIONAL— A coalition of environmental groups, a longtime Minnesota state senator, and the Fond du Lac band are calling on the Department of Natural Resources to reconsider the tailings basin dam …

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Groups seek DNR stay on PolyMet dam permit

Request comes in wake of latest deadly tailings dam collapse in Brazil


REGIONAL— A coalition of environmental groups, a longtime Minnesota state senator, and the Fond du Lac band are calling on the Department of Natural Resources to reconsider the tailings basin dam permit the agency recently approved for PolyMet, after yet another collapse of a similar type of dam, this time in Brazil.

The environmental groups and tribal officials recently asked the DNR to put a stay on the dam permit, but the agency has, so far, declined to do so. Critics of the mine plan say the method of dam construction, known as the “upstream method,” is widely considered the least safe method of tailings basin dam construction. According to National Geographic, which has reported on the Jan. 25, 2019 collapse of a dam at the Corrego de Feijao mine in Brazil, it’s an inexpensive method of dam construction largely confined to Third World countries these days. The Brazilian dam collapse has reportedly killed at least 157 people, with nearly 200 still reported missing.

The latest dam collapse comes just over three years after a similar collapse buried villages near another Brazilian mine, killing dozens, and it has prompted the mining company involved, Vale S.A., to announce that it was suspending operations at ten mines and decommissioning 19 mine waste dams using the upstream method of dam construction. In 2014, the collapse of the Mount Polley tailings basin dam in British Columbia flooded thousands of acres with toxic mud and sludge.

Environmentalists in Minnesota say the DNR has ignored the advice of experts in allowing PolyMet to use the same methods here in Minnesota.

DNR officials, however, say it’s still too early to determine what caused the latest dam collapse and argue that there are differences that should make the PolyMet dam safer than the one in Brazil. “The permitted PolyMet tailings dam, does include “upstream” construction methods, acknowledges DNR Assistant Commissioner Jess Richards. “However, there are important differences compared to the typical construction methods in Brazil.” Among them, notes Richards, is that the PolyMet dam will be built on relatively flat terrain, rather than the mountainous conditions typically found in Brazil. “And PolyMet will use a “ring-dike” basin design compared to the typical “valley” or hillside designs in Brazil,” said Richards. “Plus, Minnesota puts strict limits on the rate that tailings can be deposited to ensure adequate time for drying. It is our understanding that the tailings placement rate may not be as restrictive in other countries. Finally, Richards notes that the “ratio of surface area to height is also much greater for PolyMet than a typical dam.

But such arguments don’t convince critics of the project. “This is yet another example of the DNR brushing aside concerns about how the dam will be built and failing to require less dangerous alternatives,” stated the coalition of Minnesota environmental groups in a joint press statement issued Jan. 31. “Two-thirds of global mine tailings dam collapses involve an “upstream construction” dam.”

State Sen. John Marty, DFL-Roseville, said he strongly supports the request for a reconsideration of the dam permit. “Defenders of PolyMet say ‘we have strong mining regulations, so such a tragedy could never happen here.’ But they are wrong,” he said. “The PolyMet mine waste dam could fail. In fact, Minnesotans should know that one of the engineers who analyzed the PolyMet plan for storage of mining waste described it as a ‘Hail Mary type of concept’ that ‘will eventually fail.’”

Kathryn Hoffman, CEO of the Minnesota Center for Environmental Advocacy, said the tailings dam plan is “obsolete and dangerous.”

“The disaster in Brazil has once again shown that PolyMet’s plan to store sulfide mine waste tailings behind an unsafe dam begun in the 1950’s is a risk that Minnesota can’t bear,” she said.

PolyMet spokesperson Bruce Richardson, however, stated that the tailings dam “was one of the most studied aspects of the entire NorthMet project during its 14-year environmental review and permitting process.”

Richardson said the dam safety was reviewed by independent experts and some enhancements were incorporated into the design as a result of input from those experts. That includes the addition of a rock buttress and additional monitoring stations. “The NorthMet facility was found to meet every factor of safety for dam stability,” he said.

PolyMet will be utilizing and expanding an existing tailings basin, originally built more than 50 years ago by LTV. “There are many more active and much-larger iron-ore tailings basins (of similar design) in Northern Minnesota that have existed for decades as well,” Richardson said in a statement.

According to Jess Richards, the DNR is still considering requests to put a hold on the PolyMet dam permit as it undertakes a review of the latest Brazilian dam collapse. Yet Richards argues that his agency has already studied the PolyMet plan in depth. “DNR’s analysis of the PolyMet tailings dam as well as other mining facilities in Minnesota has been informed by technical analysis of past dam failures that have occurred in Brazil and Canada over the past few years,” said Richards. “In fact, DNR hired both Minnesota dam safety experts, as well as one of the investigators of the Mt. Polley dam failure in Canada, to evaluate the proposed PolyMet tailings dam. Their expert input was invaluable and directly led to improvements in the PolyMet design that was ultimately permitted by DNR.”

But Paula Maccabee, Advocacy Director for WaterLegacy, notes that some of the DNR’s experts raised concerns about the dam design. “We are only learning now that DNR’s own consultants called PolyMet’s tailings dam plan ‘inherently unstable and irresponsible,’” she said.

Maccabee called on new DNR Commissioner Sarah Strommen to immediately make available all of the documents analyzing PolyMet’s tailings dam. “Minnesotans are tired of secrecy when our precious natural resources and human health are on the line,” she said.

Water Legacy and the other members of the environmental coalition, including the Fond du Lac band, have appealed a number of PolyMet’s permits to the state Court of Appeals. In addition, the groups are challenging the provisions of a federal land exchange completed last year between PolyMet and the U.S. Forest Service. That lawsuit was recently reinstated by the judge overseeing the case after efforts to enact the exchange into law failed in Congress.


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