Researchers say proposed copper mine poses risks to BWCAW

An underground copper mine proposed near Ely could have consequences for both the waters and woods in the Boundary Waters Canoe Area Wilderness, two researchers said Wednesday.

Twin Metals

An underground copper mine proposed near Ely could have consequences for both the waters and woods in the Boundary Waters Canoe Area Wilderness, two researchers said Wednesday.

The scientists, commissioned to study impacts of the proposed Twin Metals mine by Northeastern Minnesotans for Wilderness and the Campaign to Save the Boundary Waters, said the potential for polluted runoff into lakes, rivers and groundwater is high.

Water running over waste rock and out of the mine’s tailings basin could become acidic, which could leach toxic metals into the waterways and increase the amount of mercury that turns into a toxic form, said Tom Myers, a Nevada-based hydrologist.

Both surface and groundwater from the mining area eventually will flow north into the BWCAW, on into Voyageurs National Park and then north into Canada.

“This area has very little buffering capability,” Myers said in a news conference Wednesday morning.


Twin Metals is proposing a large underground copper-nickel mine southeast of Ely, near the Kawishiwi River. While the mining would occur underground, the operation’s footprint above ground - roads, transmission lines, parking lots, waste storage areas and tailings basins - would create a large disturbed area that would be “like building a suburb next to the Boundary  Waters,’’ said Lee Frelich, director of the University of Minnesota’s Center for Forest Ecology.

The large disturbed area would create ripple effects in the the BWCAW, spurring changes in tree seed distribution, blocking wildlife corridors and creating an urban-like heat island that would affect the ecology of the area, he said.

“Fragmentation flows away from the fragmented area like water flows across the landscape,” Frehlich said, adding that he neither opposes nor supports the mine project and that his assessment of potential impacts was his own and not the university's.

Frelich said the project also is likely to spur increased spread of invasive species into the BWCAW forest and that any change in the pH or acidity of water is the area would have a major consequence on the adjacent forest, even changing which trees thrive and which don’t.

Twin Metals Minnesota spokesman Bob McFarlin said the predictions of environmental harm are premature because the company’s mining plan “is still a few years in the making.” The company is continually making changes in how the mine might be built to avoid environmental impacts.

“At the point in the future when the TMM project is formally proposed, that proposal will be subject to extensive environmental review by multiple state and federal regulatory agencies,” McFarlin said in a statement to the News Tribune. “Speculation on impacts prior to a formal project proposal and formal environmental review is premature.”

McFarlin, however, said preliminary tests show the project’s mine waste will not generate acidic run off. The company is “fully committed to protecting Minnesota’s wilderness, natural environment and recreational resources,” he added, noting that the mine ultimately must meet “all state and federal environmental standards in order to be approved.”

“And, to be very clear, the TMM project will not pollute the waters of the Boundary Waters Canoe Area Wilderness,” he added.


Twin Metals has been collecting environmental data in the mine area for several years but has not begun any formal environmental review process and has not yet applied for any state or federal permits. The company - now a wholly-owned subsidiary of Chile-based Antofagasta - has been analyzing mineral samples from dozens of test drill sites across the 40,000 acres to which it holds mineral rights, both north and south of Minnesota Highway 1.

While the mine would be in the BWCAW watershed, the company said it hopes to process the ore in developed areas to the south, closer to existing iron ore mining activity and in the Lake Superior watershed in areas that will minimize environmental impact. The company hopes to use some already disturbed “brownfield” areas.

In August, Twin Metals released the results of a “pre-feasibility” study on the mine saying the project has substantial reserves, would have a low cost of production and could turn a solid profit.

The mining report said the proposed mine would take about three years to build at a cost of $2.8 billion and eventually would employ about 850 people mining about 50,000 tons of ore per day. The mine is predicted to produce valuable minerals for at least 30 years - including an estimated 5.8 billion pounds of copper, 1.2 billion pounds of nickel, 1.5 million ounces of platinum, 4 million ounces of palladium,1 million ounces of gold and 25.2 million ounces of silver.

The August report also predicted the mine would have $12.1 billion in revenue over the first 10 years, and profits would pay off the cost of building the mine in just 6.4 years.

John Myers reports on the outdoors, natural resources and the environment for the Duluth News Tribune. You can reach him at
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