A Congressional Review Act move overturned a Biden-era pause on new mining leases near the Boundary Waters in northeastern Minnesota, clearing a path for Twin Metals Minnesota—backed by Antofagasta—to pursue a major underground copper and nickel project. Envir
At dawn, loons slice the Boundary Waters’ placid lakes, and by nightfall bright stars break across the dark. It’s a landscape federal protections were built to preserve—more than a million acres of wilderness near the Canadian border. about four hours north of Minneapolis. defined by lakes. streams. and islands with hardly any human infrastructure.
Now, that quiet has a new pressure point at its edge. A company called Twin Metals Minnesota—an affiliate of the Chilean copper giant Antofagasta—has been pursuing copper and nickel mining just outside the southern boundary of the Boundary Waters. The stakes sharpened earlier this year when Congress and President Donald Trump moved to remove a major obstacle that had stood in the project’s way: the House and Senate overturned a Biden-era mining ban in the region. allowing Twin Metals to revive its mining push within the watershed.
Environmental advocates say that decision matters because the Boundary Waters’ hydrology means the consequences of a mine don’t stay contained. Even though mining and other extractive industries are prohibited inside the wilderness area. pollution from a project nearby could flow into the protected ecosystem—potentially harming forests and wildlife and undermining livelihoods for Native Americans who fish. hunt. and harvest wild rice.
“This mine is going to pollute,” said Ingrid Lyons, executive director of the advocacy group Northeastern Minnesotans for Wilderness, which leads the campaign Save the Boundary Waters. “It’s not a matter of if this mine is going to pollute, it’s a matter of when.”
Twin Metals disputes that framing. The company says concerns are rooted in misinformation and argues it can operate safely. It also points to the approvals process: before any mine could begin. a project would have to meet both federal and state environmental safeguards—Minnesota’s. he says. are particularly strong.
On another front. Twin Metals leans into a different argument: that the world needs metals such as copper. nickel. and cobalt to build clean-energy technologies like batteries for electric cars. If those minerals aren’t produced in Minnesota. the company argues. they may come from other countries with less rigorous environmental regulations.
The clash is more than environmentalists versus a mine. The question Twin Metals’ advocates and opponents both circle—each for different reasons—is whether the tradeoffs are worth it, and whether the risks can be controlled where the watershed is most vulnerable.
The project Twin Metals wants to build centers on the Duluth Complex. one of the world’s largest unexploited deposits of copper and nickel. Twin Metals says it would excavate and crush ore—metal-rich rock—down to as far as 4. 500 feet underground. then bring it up to the surface. There. the company would remove compounds containing copper. nickel. and other minerals. which it would ship elsewhere for refining into usable metals.
Twin Metals says it would return some of the leftover rock, known as tailings, back underground. The rest would be placed into a pile on land nearby. The company has also said it has put more than a decade of work into the planned mine, investing about $650 million.
But the project has repeatedly run into federal roadblocks.
In 2022, the Biden administration canceled Twin Metals’ two mineral leases. Those leases gave the company rights to explore and mine in certain areas but did not amount to approval for specific projects. Then. in early 2023. the administration imposed a 20-year pause on approving new leases near the Boundary Waters in the region where Twin Metals had planned to mine.
“In protecting this special place for future generations, I have made this decision using the best-available science and extensive public input,” then-Interior Secretary Deb Haaland said when announcing the pause.
That temporary ban was later overturned. Congressional Republicans, led by Minnesota Rep. Pete Stauber, used the Congressional Review Act—an obscure law—to undo the ban and also prevent future administrations from issuing similar protections without an act of Congress.
The rollback didn’t reinstate the two mineral leases that were canceled in 2022. Twin Metals had challenged the lease cancellations and was still waiting for a court decision at the time described. Congress is also considering a bill that would re-issue those leases to Twin Metals. If the company acquires leases. federal and state agencies would still conduct reviews that could block the project. and even with federal approval. the Minnesota Department of Natural Resources could decide not to grant a permit.
Twin Metals says the mine’s design is built to reduce harm. The company describes an underground operation with a small surface footprint, including a processing facility about the size of a Super Target.
It also argues its approach avoids a water pollutant known as acid rock drainage. According to the company, metal in the ore is bound to sulfides. When sulfides react with air and water, they can form sulfuric acid—toxic to plants and animals—and leach heavy metals such as arsenic out of rock.
Kathy Graul. a Twin Metals spokesperson. told Vox. “Twin Metals Minnesota is focused on responsibly developing the minerals in the Duluth Complex. Any proposed project in this region. including Twin Metals. must undergo a yearslong. multi-agency regulatory review before earning permits to begin construction of a mine.”.
Environmental advocates and scientists aren’t persuaded that permits can eliminate the risk.
Lyons said that if the mine is built, there would be runoff and mine discharge, and that discharge would contain sulfate. She also disputed the company’s insistence that the drainage would not be acidic.
Lee Frelich. a forest ecologist at the University of Minnesota who has studied the impacts of sulfide mining. described concerns about harmful chemicals moving through the system and reaching the Boundary Waters. He said those chemicals could damage trees and aquatic animals through cascading effects.
Emily Onello, a physician and medical researcher at the University of Minnesota Medical School Duluth, added that sulfate pollution could impair the growth of wild rice, a critical and sacred food resource for Indigenous peoples in the region.
Twin Metals and supporters of the project recognize that mining historically caused serious environmental problems. Their position is that modern mining is different—cleaner, safer, and subject to stronger oversight.
Regulations have indeed tightened over decades, and companies seeking permits now must comply with them. Graul pointed to that reality, telling Vox that projects must prove they can meet stringent Minnesota environmental standards before moving forward.
But what neither side can fully guarantee is a total absence of pollution.
Dustin Mulvaney, a researcher at San José State University who studies the impacts of resource use, said, “New mines are going to be cleaner, they’re going to be better, they’re going to be better permitted—but they also are going to have impacts.”
That uncertainty is echoed in a 2022 report from the Interior Department that stated: “Hardrock minerals mining of sulfide-bearing rock. no matter how it is conducted. poses a risk of environmental contamination due to the potential failure over time of engineered mitigation technology.” The report also noted that many of its authors were still government employees.
The Interior Department’s warning is blunt: mitigation technology can fail over time, and drainage problems can last for decades or even centuries.
Mulvaney said it comes down to whether society is willing to accept those risks.
The political fight has sharpened into a question of placement, not just extraction.
Congressman Stauber told me he believes the minerals should be mined where they are. saying the mine shouldn’t pollute if approved by the state. Julie Lucas. executive director of MiningMinnesota and a former water resources director for Twin Metals. has argued that producing more minerals is fundamental to the energy transition. Lucas said. in a 2024 commentary in The Minnesota Star Tribune. “Mining is fundamental to our lives today and more important than ever for our future.” She also said. “We aren’t doing the Earth any favors by declaring a definitive ‘no’ against potential mining projects.”.
Opponents counter that “no” isn’t the issue—it’s where.
Grace Wu, who studies the tradeoffs of clean-energy technologies at the University of California Santa Barbara, said there is “almost always a better place to build that infrastructure.”
Mulvaney pointed out that there are other places to mine copper in the United States, most of which comes from Arizona. He also said there is already an active nickel mine in Michigan.
On recycling, Mulvaney said the United States throws out a lot of copper each year, and in 2023 only about a third of post-consumer copper was recycled. He argued that politicians pushing for more mining have not focused on that shortfall.
“There’s no place that has to inherently be mined,” Mulvaney said.
Lyons and other opponents say Minnesota’s wilderness is still one of the few remaining intact expanses where the public interest should weigh most heavily. Lee. the University of Minnesota ecologist. argued that the value of such areas for future generations is infinite—dwarfing what a single mine might bring.
Alex Falconer, a Democratic state Rep. in Minnesota who also works for Save the Boundary Waters, said the issue isn’t mining in general but mining “precisely here.” “It’s just the wrong place for this type of mine,” he said. “Society can pick and choose where mining should happen.”
The comparison that drives some opposition is precedent at other protected landscapes. During the first Trump administration, then-Interior Secretary Ryan Zinke announced a 20-year ban on hard-rock mining near Yellowstone National Park. Zinke said at the time that there were “places where it is appropriate to mine and places where it is not.”.
For the Boundary Waters fight, what comes next is murky—especially with the Trump administration unlikely to block Twin Metals. One factor supporters of the project say may help Twin Metals’ cause is the company’s lobbying effort: a lobbying firm hired by Twin Metals was founded and chaired by David Bernhardt. Trump’s other former Interior Secretary.
If the federal path opens, the battle shifts to the state.
Falconer is pushing a Minnesota state bill aimed at preventing regulators from issuing permits for copper mining in the Boundary Waters and its headwaters. Falconer said he hopes it will be brought to a vote early next year and, pending the results of the midterm elections, become law.
“The watershed of the Boundary Waters is sacred to me,” Falconer said. “It’s off limits.”
If those efforts fail and Twin Metals begins digging up metals, Lyons said it would serve as a warning to other natural treasures across the country.
“If something bad can happen in the boundary waters,” she said, “it can happen anywhere.”
Boundary Waters Twin Metals Minnesota Antofagasta copper mining nickel mining Duluth Complex Congressional Review Act Deb Haaland Pete Stauber Minnesota environmental safeguards acid rock drainage wild rice Native Americans wilderness protection clean energy metals