What you need to know about copper-nickel mines in Minnesota

Long before he was elected, President Donald Trump promised to reinvigorate mining in northeast Minnesota. Since January, his administration has taken many actions to clear the way for new hardrock mines, which would be the first in Minnesota.

Each mine could supply copper and nickel, crucial minerals for electric vehicles and electrification in general. Yet the mines pose threats to lakes, rivers and wild rice. Years of debate, study and legal action have snarled two of the mine proposals in regulatory issues. A third is beginning environmental review. Here’s what you need to know about the three main copper-nickel mine proposals in Minnesota.

The Twin Metals mine would be dug underground in Lake County, between Babbitt and Ely. It would produce 20,000 tons of ore a day, including copper, nickel, cobalt and platinum group metals. This mine would be in the watershed of the Boundary Waters Canoe Area Wilderness.

NorthMet would be an open-pit mine near Babbitt, and the mine plan calls for producing 32,000 tons of ore, mostly copper, each day. The ore would be processed at a former LTV Steel site in Hoyt Lakes. The project was first proposed by the company PolyMet.

Talon Metals’ Tamarack Mine would be an underground project in Aitkin County, a part of the state without any large-scale mining. It would extract 3,300 tons a day of nickel, copper and platinum group metals. Those would be shipped to Beulah, N.D., for processing at a former coal mine. The company intends to supply nickel to Tesla for its electric vehicle batteries.

Twin Metals is a wholly owned subsidiary of the Chilean mining company Antofagasta. The company has a focus on copper mining, and all of its operating mines are in Chile.

The NorthMet project was originally proposed by a subsidiary of the Swiss conglomerate Glencore. In 2022, the company pleaded guilty in a bribery and corruption case and agreed to pay $1.1 billion in fines. Charges included a global chain of bribes and a scheme to manipulate oil prices at two U.S. ports. Today, NorthMet is owned by NewRange, a partnership that includes Glencore and Teck Resources, a Canadian company that has been exploring a deposit near NorthMet.

Talon Metals has a registered headquarters in the British Virgin Islands but is traded on the Canadian stock exchange. The company owns 51% of its Tamarack Mine project, and the British-Australian conglomerate Rio Tinto owns the remaining 49%. Talon has entered an agreement with Rio Tinto to purchase up to 60% interest in the mine, if it hits certain benchmarks.

NorthMet’s owner did not estimate when it might start production, but a spokesman said permitting and pre-mine construction could take up to 5½ years. This proposal is the furthest along of the three mines. The company said it was re-tooling its plan last year after losing a key federal wetland permit and after a judge recommended rejecting a permit to mine over waste handling issues. The Trump administration boosted the project when it put it on a list of projects to fast-track earlier this year.

A spokeswoman for Twin Metals did not have an estimate for a date when the mine could open. It still needs to secure mineral leases that were revoked by then-President Joe Biden, but that the Trump administration said they would restore. Biden also banned any type of mining in 225,000 acres of Superior National Forest, including the Twin Metals site. Even if the leases are restored, Twin Metals will have to re-start a lengthy environmental review.

Talon officials estimate they will begin mining in 2029. The company has started environmental review with the state of Minnesota. It submitted a big-picture plan for its mine which will help the state decide what environmental issues need to be studied.

Proponents of mining say these projects could be a lifeline for the industry, as taconite mines face long-term pressure and short-term shocks. This year, both the Minorca and HibbTac mines were idled and workers laid off. The automotive industry, taconite’s main buyer, is struggling to navigate an edgy market and tariff shocks.

The mines would provide copper, a metal in high demand for its ability to conduct electricity, and nickel, a metal that has been used often in electric vehicle batteries.

Twin Metals estimates it would employ 700 people full-time. The NorthMet project would employ at least 360 people full-time. Talon’s Tamarack Mine would employ 300 people.

Twin Metals estimates its mine would operate for 25 years. NorthMet would mine for between 16 and 20 years. Talon has pegged its lifespan for the Tamarack mine at seven to 10 years.

The main concern is the potential for toxic drainage from the mines, which would likely come from waste rock and tailings, or the material left over after ore has been processed.

If not handled properly, the resulting waste could release sulfates into the surrounding watershed. Sulfate is highly toxic to wild rice and other aquatic plants, and Minnesota has a water quality rule limiting it in places where rice grows, though it has not been well enforced in the past. In some lakes, sulfate also plays a role in helping mercury build up in aquatic life.

Another risk is that these sulfides, if exposed to air and water, could create sulfuric acid, commonly called acid mine runoff. This happened decades ago at a former iron mine not far from the Twin Metals site, which stripped sulfides off the top of a taconite deposit and then left the minerals in piles exposed to the elements. The site has since been mitigated, but it still leaks sulfates into nearby Birch Lake.

Twin Metals asserts that its mine would not create acid mine drainage, in part because it would be putting some of its waste back into the underground pit after processing. Talon Metals’ underground mine would ship everything it pulls out of the ground to North Dakota for processing.

NorthMet had planned to put processing waste into an old taconite waste dump, but that basin leaks. A judge recommended denying a major permit because of the waste plan, so NewRange to studying alternatives.

In a watershed, falling rain and melting snow all flow to the same place, like a major lake or river. The watershed that each proposed mine would sit in is important because it reveals areas downstream that could be affected if a project releases pollution.

The Twin Metals mine is in the Rainy River watershed, which flows through the Boundary Waters Canoe Area Wilderness. This has made it the most controversial of all three projects, because of the proximity to the beloved, 1.1 million-acre matrix of streams, bogs and lakes.

In fact, a federal study in 2022 determined that a mine in that watershed risked contaminating the Boundary Waters, even if modern mitigation measures were put in place.

NewRange’s NorthMet project is in the St. Louis River watershed, which flows into Lake Superior. That project has also faced major environmental hurdles in part because the Fond du Lac Band of Lake Superior Chippewa has its own water quality standards downstream of the mine, which served to scuttle the mine’s wetland permit.

Talon’s Tamarack Mine is in the Mississippi River watershed. The Mille Lacs Band of Ojibwe have expressed concern about contamination nearby in some of the most productive wild rice beds in the state, including Rice Lake National Wildlife Refuge.

Copper and nickel are mined around the world. In the United States, the only active nickel mine is the Eagle Mine in Michigan’s Upper Peninsula, which opened in 2014. Copper is mined in western states including Arizona, New Mexico, Utah and Nevada.

Some in the industry argue it is better for minerals to be mined in Minnesota, because of the environmental protections here. Most of the world’s nickel is mined in Indonesia, where researchers have found that mines have accelerated deforestation and harmed the health of villagers who live nearby. Indonesian President Prabowo Subianto canceled mine permits for four companies in June 2025, in response to a report about forest destruction on the coral-reef-ringed Raja Ampat islands.

Minnesota has the right geology.

The Twin Metals and NorthMet projects would mine parts of the Duluth Complex, a massive area of sulfide minerals that flowed across the Arrowhead region 1.1 billion years ago, as lava flowed out of a midcontinent rift.

The Talon project is proposing to mine the Tamarack Intrusion, a geologic formation that is not as well studied as deposits to the north. The tadpole-shaped intrusion also formed out of the midcontinent rift, though its most concentrated deposits flowed through relatively narrow underground channels. Talon has a robust drilling program that found nickel concentrations as high as 12.65% — which would put it on par with some of the richest nickel deposits in the world.