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Should PolyMet’s proposed mine be compared to the Flambeau Mine?

Laura Gauger was living in northwestern Wisconsin when a small copper mine was built near Ladysmith. Now she’s written a booklet comparing the now-closed mine to PolyMet’s planned mine.

The Minnesota Department of Natural Resources (DNR) is giving the public more time to digest and comment on the massive Environmental Impact Statement on PolyMet’s proposed NorthMet copper-nickel mine in northeastern Minnesota. The new deadline is Dec. 21. Environmental activists have spent hours hunched over their computers, critiquing the document’s analysis and looking for potential problems with the project.

One campaigner who has already logged a lot of time analyzing similar documents is Laura Gauger. She was living in northwestern Wisconsin when a small copper mine was built near Ladysmith. The Flambeau mine, operated by a subsidiary of Kennecott, itself a subsidiary of Rio Tinto, operated just 140 feet from the Flambeau River from 1993 to 1997. Gauger and others fought the mine and monitored its activities. Years later, she couldn’t help noticing when advocates of the PolyMet mine in Minnesota pointed to the now-closed Flambeau mine as an example of a successful operation that did not hurt the environment.

“I saw how people were misled in Wisconsin,” Gauger said, “and I’m concerned that it’s happening here, too.”

Gauger has written a 16-page booklet, complete with a DVD packed with original documents, comparing the two mines.

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The much smaller Flambeau mine contained ore so highly concentrated that it was economically feasible to ship it to Canada for processing, so it produced none of the tailings (fine waste rock from milling and concentrating) that can be a challenge to store safely.

According to Gauger’s analysis:

Flambeau mine
  • Pit size: 32 acres
  • Wetland impact: 19 acres
  • Water treatment: five years
  • No tailings
  • Nine million tons of waste rock
PolyMet mine
  • Pit size: 528 acres
  • Wetland impact: 7,000 acres
  • Water treatment: indefinite
  • 225 million tons of tailings
  • Up to 308 million tons of waste rock

Of course there are similarities between the two mines. When mining was finished, workers at the Flambeau mine buried overburden (rock and soil dug up to expose the underlying mineral deposit) in the exhausted mine pit and allowed it to fill with water. This is the same “subaqueous” disposal method planned for PolyMet’s waste rock. Computer models prior to operation of the Flambeau mine predicted high levels of certain minerals in groundwater within the pit. But those predictions didn’t come close to actual levels monitored after closure. Sulfate turned out to be nearly twice as high; manganese, 76 times as high; iron, nearly 47 times as high; and copper, 62 times as high.

According to Ann Coakley, director of the Wisconsin DNR’s Waste and Materials Management Program, it’s taking longer for the pit to stabilize because the company used finer-grade limestone to buffer the mineral-laden rock than planned. But she says monitoring wells outside the pit, close to the river, show groundwater meets state standards.

“It’s not impacting the Flambeau River, and that’s the measure of success,” she said. “That waste pit could have high manganese for decades, if not centuries, and as long as it’s not moving outside of the waste pit and to the river, it’s not a problem.”

In an email, Flambeau Mining Company’s Dave Cline wrote, “All monitoring of the mine site continues to show that the Flambeau River was, is and remains protected … we are proud of our demonstrated commitment to and longstanding positive environmental record at the Flambeau Mine site.”

Just 140 feet of bedrock separates the river from the backfilled pit. Gauger and others worry that the rock could eventually allow migration of contaminated groundwater into the river. Coakley dismissed that concern.

“The bedrock is not very permeable at all; it’s quite tight; there are very few fractures,” she said. “So water moves very, very slowly, and will never get to the Flambeau River.” Nevertheless, the state plans to continue monitoring the pit and the river for decades.

One oddity about the Flambeau mine is that a small area was not reclaimed because the city of Ladysmith asked the company to leave its buildings and a road there for re-use. The company built a bio-filter and later an infiltration basin in an attempt to clean contaminated stormwater flowing from the area. Neither of these passive water treatment systems has proved effective. Now, a nearby small stream is loaded with enough copper and zinc to land it on the state’s list of impaired waters.

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Laura Gauger joined two environmental groups to sue the company for the pollution. In a federal court case that rivals a Dickens story for twists and turns, the trial court ruled that the company had violated the Clean Water Act, but the appeals court ruled that it wasn’t the company’s fault, because the Wisconsin DNR had failed to place limitations on contamination for the stream. Rio Tinto went after the plaintiffs for legal costs, in what Gauger describes as a campaign to discourage such citizen lawsuits.

The DNR’s Ann Coakley said the state has no plans at the moment to clean up the stream. “It’s not a very high priority compared to some others on the list,” she said. “It only flows during rainfall and snowmelt events, and the biggest problem is we don’t know for sure why the copper concentration is high.” Coakley said the ground around the entire area is naturally high in copper, and the stream wasn’t sampled before the mine was built.

Gauger draws on her study of the Flambeau mine to criticize Minnesota’s environmental study of the proposed PolyMet mine. In her comments to the Minnesota DNR, she says the study fails to provide baseline water quality data on surrounding streams, fails to explain limitations in computer modeling, and promises use of passive water treatment systems that didn’t work at Flambeau.