Outdoor enthusiasts travel by canoe through several of the hundreds of fresh water lakes that make up the Boundary Waters in the northern woods of Minnesota.
Andrew Lichtenstein | Corbis News | Getty Images
The Senate on Thursday overturned a mining moratorium in Minnesota’s Superior National Forest, a boon for a Chilean mining company subsidiary and a stinging loss for environmentalists trying to protect the Boundary Waters Canoe Area Wilderness.
The chamber voted 50-49 to overturn a protection imposed by President Joe Biden in 2023 that he set for 20 years. It clears the way for a long-stalled mine project proposed by Twin Metals Minnesota to restart plans to access the immense stores of copper and other minerals in the Superior National Forest near the Boundary Waters. It’s the latest step in a long battle over mining in the area, which has seesawed for years between Democratic and Republican administrations as environmental groups warn the project could pollute the country’s most visited wilderness area.
The mine sought by Twin Metals, a subsidiary of Chilean mining conglomerate Antofagasta, seeks to access copper, nickel, cobalt and platinum buried deep under the Superior National Forest. While the site itself is outside of the Boundary Waters and the company dismisses pollution concerns, opponents say it would inevitably spill toxic chemicals into the Boundary Waters.
“Twin Metals Minnesota is one of several companies focused on responsibly developing the minerals in the Duluth Complex, which is the world’s largest known undeveloped copper, nickel, cobalt and platinum group metals deposit,” Twin Metals spokesperson Kathy Graul said in a statement to CNBC. “A significant portion of these resources were locked up as a result of the mineral withdrawal enacted in 2023, negatively impacting communities across the Iron Range.”
“The Twin Metals team looks forward to a robust discussion and engagement with our communities through any future regulatory processes,” Graul added.
Republicans who pushed the resolution lauded the result. The change went forward under the Congressional Review Act procedure that allows Congress to undo new executive rulemakings by a simple majority vote. It cleared the House in January.
“A major victory for America and Minnesota’s 8th Congressional District was secured today,” Rep. Pete Stauber, R-Minn., said in a post to X. “The Senate just passed my bill to reverse Biden’s illegal mining ban in the Superior National Forest – it’s now headed to the President’s desk!”
The vote came over the objection of Democrats and two Republicans, Sens. Thom Tillis of North Carolina and Susan Collins of Maine, who warned of irreparable harm to the Boundary Waters and irregular use of the Congressional Review Act that could come back to bite the now-majority Republicans if Democrats control the Senate.
The Boundary Waters was established as a federal wilderness area by a 1978 law. Motorized boats and other vehicles are mostly prohibited on the nearly 2,000 lakes spanning 1.1 million acres in northeastern Minnesota bordering Canada.
A lake within the Boundary Waters Canoe Area Wilderness in Ely, MN. (Photo by Salwan Georges/The Washington Post via Getty Images)
Salwan Georges | The Washington Post | Getty Images
Sen. Martin Heinrich, D-N.M., the ranking member of the Senate Energy and Natural Resources Committee, said the vote was a “dark day” and a “stain” on the Senate.
“I can tell you, as somebody who has been a natural resources trustee, who has had to negotiate with copper companies in my own state, that this type of copper mining has never been done without polluting the water. Never, not once,” he said in a floor speech before the vote. “So we’re guaranteeing that we’re going to pollute the Boundary Waters.”
The resolution was also passed over the objections of the Minnesota Senate delegation, Sens. Amy Klobuchar and Tina Smith, who are both Democrats.
“You can support mining, but that does not mean that you support every mine in every place,” Smith said. “Whatever the outcome of this vote this afternoon, we will not stop fighting, and we will not stop our work to protect the Boundary Waters.”
Actor Nick Offerman holds a discussion in the U.S. Capitol on Wednesday, April 15, 2026.
Bill Clark | CQ-Roll Call, Inc. | Getty Images
Overturning the mining moratorium also drew considerable outside pressure, including from figures like actor Nick Offerman.
“Enjoying the Minnesotan/Canadian wilderness by canoe or other lesser watercraft is one of our nations greatest available pastimes, and one I have personally enjoyed my entire life,” Offerman said in a post to X on Wednesday. “We must protect these public lands from the rapacious capitalists threatening to turn them into a poisoned wasteland.”
Ingrid Lyons, executive director of the advocacy group Save the Boundary Waters, said the vote goes against the will of Minnesotans.
“Today is a dark day for America’s most beloved Wilderness area, the Boundary Waters Canoe Area Wilderness, and a stark warning call for public lands nationwide,” she said in a statement. “Minnesotans and the American public writ large have been loud and clear — this iconic place needs to be protected. Today, by the very people who claim to represent them, they were ignored, and even worse, silenced.”
Public lands have been a flashpoint during this Congress. Some Republicans pushed to sell off a large portion of federally owned property as part of their tax and spending bill last year, which was quashed after the resistance of outdoor and hunting groups and the staunch opposition of members of the Montana delegation.
The bill now heads to President Donald Trump’s desk. He is expected to sign it.