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Twin Metals quietly moves its waste storage closer to the Boundary Waters

Twin Metals says its new storage method will reduce risk of pollution, but critics say the company just "made a bad plan worse."

Twin Metals says its new storage method will reduce risk of pollution, but critics say the company just "made a bad plan worse." Aaron Lavinsky, Star Tribune

Twin Metals, a Minnesota company owned by Chilean mining giant Antofagasta Minerals, is closing in on building its new copper mine. The location: Ely, right next to Minnesota’s treasured stretch of silent lakes and untouched wilderness, the Boundary Waters.

Environmental groups are, frankly, upset. This kind of mining produces sulfide-bearing ore. It’s pretty much harmless if it stays in the ground, but once it comes into contact with air, rain, or snow, whatever runs off becomes toxic sulfuric acid.

Opponents fret the mine could end up contaminating the lakes, the groundwater, and the animals, leaving the Boundary Waters irrevocably damaged.

Antofagasta has experienced a few spills while attempting similar mining operations in Chile—including dumping some 130,000 liters of copper concentrate into the Choapa River in 2009.

Twin Metals claims it has everything under control. The company announced last week that it planned to use a new method to store waste known as a “dry stack.” Normally, tailings—everything left over after you get the ore and minerals out of the rock—would be stored in a pond with a dam to keep them out of the surrounding environment. (These have been prone to failure.)

But with a dry stack, the tailings are instead squeezed down into “low-moisture, sand-like deposits” and stored in a “lined ground facility” near the site. Twin Metals is arguing it’s a win for those worried about the impact on nature. After all, there can be no dam failure if there is no dam.

But a lot of people—including those involved in the grassroots organization Save the Boundary Waters—aren’t impressed. Under the new plan, only about half of the tailings would actually be underground. The other half, instead of being carted away to a storage facility to be built in Babbitt, would be sitting around in a “huge, lined pile,” as MPR put it, near the mine’s processing plant.

Which is just a couple of miles from the southern edge of the Boundary Waters.

“What they [Twin Metals] didn’t say as publicly was that they were moving the waste storage closer to the Boundary Waters,” spokesperson Jeremy Drucker says. “They’re going to make a bad plan worse, essentially.”

Twin Metals also insisted that the byproduct would be “non-acid-generating” and “almost completely free” of the sulfides. But Save the Boundary Waters chair Becky Rom told the Star Tribune the tailings would still be toxic, full of heavy metals that could leech out and poison the water.

Meanwhile, Chris Knopf, director of Friends of the Boundary Waters Wilderness, told the Tribune that the new storage method “is an improvement in the sense that drinking a cup of rubbing alcohol is an improvement over drinking a cup of bleach.”

Twin Metals spokesperson David Ulrich sent a statement saying locating the stack near the plant "reduces potential impacts from transporting tailings long distances."

"...All of Minnesota's watersheds hold value, and our project supports the protection of our environment," he said. 

But in the end, Drucker says, there’s probably nothing the company can say that will put him and other objectors at ease.

“As the issue continues on, Twin Metals is going to try to distract from the overall point,” he says. “This is the wrong mine in the wrong place, and there’s no way they can mine sulfide ore copper safely.”