Mining Minnesota’s Canoe Country

A project could poison one of North America's most important watersheds for years.

A mining company has set its sights on northern Minnesota’s fabled canoe country.

If PolyMet gets its way, the first open-pit copper-nickel mine in the region will begin operations later this year, raising fears that the mine will leak acid and toxic metals into wetlands and waterways that feed into Lake Superior.

PolyMet’s NorthMet mine would sit along the Mesabi Range in Superior National Forest, about a mile south of an existing taconite mine. The company would dig up nearly 1,000 acres of spruce-dominated wetlands to depths of 700 feet, stockpiling waste rock nearby. It would haul ore to a nearby refurbished taconite plant for processing, and jettison tailings in an existing taconite basin. Over 20 years it plans to excavate some 533 million tons of waste rock and ore. The project, PolyMet says, would create up to 500 jobs during peak construction and 360 during operations.

Miners have dug sprawling open pits in Minnesota for more than a century. But unlike most mined ore, the region’s copper-nickel is locked in a sulfide- containing matrix. Once exposed to oxygen and water, sulfides oxidize to produce sulfuric acid and release metals in soluble forms, including mercury, copper, iron, and nickel. Acidic and metallic drainage from the mine pit, waste-rock stockpiles, and tailings basin could continue to leach into ground and surface water long after the mine is closed. PolyMet itself estimates that reclamation will take decades—and that’s if nothing goes wrong.

Environmentalists and local residents fear the effects of sulfide mining in this pristine area, home to three Important Bird Areas and effectively the headwaters of the Great Lakes. They point to disasters like the Berkeley Pit, an abandoned open-pit copper mine in Butte, Montana, with deadly waters; hundreds of snow geese died when they landed there in 1995. Hoping to prevent a similar calamity in their backyard, opponents are rallying to gather statements against the mine. The public comment period on the supplemental draft environmental impact statement closes March 13.

“Here is a mining practice that generates toxic materials in a really wet environment at the headwaters of a critical watershed,” says Matthew Anderson, Audubon Minnesota executive director. Mercury is “going to work its way into water, up through the food chain and cripple habitat and impact birds.”

NorthMet would drain into tributaries of the St. Louis River, a stream that ends up in Lake Superior. “It’s the most important on-reservation fishery resource for the Fond du Lac band,” says Nancy Schuldt, the reservation’s water projects coordinator. She’s concerned that sulfates from mining would raise mercury levels in a river that already has fish advisories due to the heavy metal.

Band members also contend that elevated sulfates in downstream waters might diminish or wipe out wild-rice beds in the upper St. Louis watershed—an important crop for area tribes, non-Indians, and migrating waterfowl and other birds. Sulfate levels already exceed the state’s stringent “wild-rice standards” in many places. “This project will just add to those impacts,” says Schuldt. “That’s one of the reasons we believe that it should not be permitted.”

PolyMet proposes treating water from the mine pit and captured from the stockpiles and tailings basin in a wastewater treatment plant. Minnesota law will require a financial package before permits are issued to ensure that reclamation and water treatment will continue as needed, even if PolyMet goes out of business. How long? “We think it’s a matter of decades,” says Brad Moore, PolyMet executive vice president of environmental and governmental affairs.

Civilization needs copper for thousands of uses. The average American home contains 400 pounds. One wind turbine contains nearly five tons. “We need the minerals,” says Moore. “We have the know-how, we’ve got the labor, the financial resources, and the laws to do it here as well as or better than anywhere else in the world.”

NorthMet isn’t the only threat around. Six copper projects are planned, including the gigantic Pebble Mine in Alaska, which, according to the EPA, threatens the world’s largest sockeye salmon fishery. Another company, Twin Metals Minnesota, is in the preliminary stages of planning a mine that would drain into the federal Boundary Waters Canoe Area Wilderness.

Opponents like Steve Piragis, a canoe outfitter in nearby Ely, says the water-rich region is the worst place possible for a sulfide mine. “We need the jobs, and we’re not against mining,” he says. “We’re just against mining sulfide ore in the Boundary Waters watershed and in the Lake Superior watershed. This is just not the place to do it.”

Speak Up!

Sulfide mining puts the water, birds, and natural treasures of the St. Louis River and the Lake Superior watershed at risk. Urge EPA administrator Gina McCarthy to protect our natural heritage.

To add your voice, visit

To correct an editing error, this article has been revised to clarify that the concerns about PolyMet's proposed NorthMet mine center on the Lake Superior watershed, not the Boundary Waters watershed.