Are you confident the proposed PolyMet mine would avoid polluting Minnesota’s water?

“[The] DNR has described a mine that functions perfectly, exactly as intended, that has no problems whatsoever…but they don’t explore scenarios in which something goes wrong.” — Kathryn Hoffman, an attorney for the Minnesota Center for Environmental Advocacy

A reverse osmosis machine owned and developed by Polymet operates in a test facility Friday, September 27, 2013 in Virginia, Minn. The device will clean water coming from the mine site. Derek Montgomery / For MPR News

“Minnesotans have until Thursday to comment on the environmental analysis of the proposed PolyMet mine, a huge document containing detailed plans on how the company would keep pollutants from the mine and tailings basin out of nearby lakes and rivers. That plan hinges on new technologies and engineering that PolyMet added after its last proposal was sharply criticized four years ago,” writes MPR News reporter Dan Kraker.

Along the north side of the vast tailings impoundment, the company plans to build a five mile long wall to capture water that runs through the tailings and picks up metals, sulfate and other pollutants. Company officials are confident the process will work.

“The cut off wall that we’re putting in, that will go all the way down to bedrock,” Cherry said. “Those type[s] of technologies have been around for some time. This isn’t like a new technology that we’re trying out for the first time here.”

Similar walls have proven successful at mines from Montana to Alaska, and at landfills around the country.

But few have been built as large, said Dave Chambers, president of the Center for Science and Public Participation in Montana.

“The concern with the slurry walls that are that big,” he said, [is] “are you going to be able to guarantee that you’re going to be able to anchor that slurry wall in bedrock along that whole perimeter?”

Chambers said the bedrock could fracture beneath the wall when it’s installed, which could allow water to seep through.

Today’s Question: Are you confident the proposed PolyMet mine would avoid polluting Minnesota’s water?