Boundary Waters advocacy groups say they are concerned that a proposed platform for the next Republican president would have devastating environmental impacts by allowing mining in a protected, roughly 225,000-acre swath of national forest land adjacent to the Boundary Waters Canoe Area Wilderness.

Project 2025 is a proposed platform for the next president that was organized by the conservative think tank Heritage Foundation. The project has been disavowed by President-elect Donald Trump, even though some of his former cabinet members helped assemble it and he has praised their work on it previously. Democrats have helped raise the profile of Project 2025 with frequent criticism of its contents, and say it must be viewed as a blueprint for a possible second Trump presidency.

Vice President Kamala Harris attacked the Trump-aligned Project 2025 during the Sept. 10 presidential debate between the two candidates and throughout her campaign.

One paragraph in the nearly 900-page document calls for the president's administration to abandon the "withdrawal" of land for mineral leasing that President Joe Biden's administration ordered in 2023, which was meant to protect the Superior National Forest for 20 years.

Chris Knopf, executive director of Friends of the Boundary Waters, said he is "very concerned about what the future of the Boundary Waters holds" if Trump is elected and mining is allowed.

"This would be catastrophic, and it would absolutely decimate the Boundary Waters as we know it," Knopf said.

Project 2025 also calls for removing the protections on the Thompson Divide of White River National Forest in Colorado, and the 10-mile protected buffer around Chaco Culture Historic National Park in New Mexico. It says the president should "revisit associated leases and permits" for both energy and mineral production in the three listed areas, and consult with state officials on it.

Officials with Project 2025 and the Heritage Foundation did not respond to requests for comment.

The 225,000-acre area in question does not include the Boundary Waters, but Knopf said mining could still harm plants and wildlife in the protected wilderness because it's in the same watershed and would carry any pollutants into it if there was a leak.

"The issue with this type of mining is that the ore vein has sulfide in it, and when that's exposed to air and water it creates sulfuric acid, and that's why there's a big water risk," Knopf said.

Twin Metals Minnesota, a subsidiary of Chilean mining giant Antofagasta, had proposed a copper-nickel mine for the affected area in the Superior National Forest. Biden canceled the company's mining leases in 2022 and then enacted the 20-year protection on the area.

In a statement, Dean DeBeltz, Twin Metals' vice president of external relations and project operations, said the company has "no affiliation with and has never met with anyone from Project 2025." He added that the company still has plans for the area.

"We at Twin Metals are focused on advancing a clean energy minerals project, outside of the Boundary Waters Canoe Area Wilderness, that will be essential to our nation's ability to transition to a cleaner future, bolster national security, create American jobs and strengthen domestic supply chains," DeBeltz said.

While the Project 2025 mandate came out over a year ago, Knopf said the section singling out the Boundary Waters came on his group's radar in the last month. Since then, the nonprofit's staff members have been fearful that a Trump presidency could ruin the environmental beauty of the Boundary Waters, considered by many to be Minnesota's most iconic wild area.

Ingrid Lyons, executive director of the nonprofit group Save the Boundary Waters, said she believes the mandate is a "very telling document that serves as a stark reminder of what is at stake for our country's public lands" and that removing the protections would be a "major setback on so many levels."

The U.S. Senate is still considering a bill from Republican Rep. Pete Stauber, who represents Minnesota's Eighth Congressional District, that seeks to remove Biden's withdrawals on mining leases for the Superior National Forest. That bill was approved by the GOP-controlled U.S. House in April by a vote of 212 to 203. A spokesperson for Stauber did not return requests for comment.

Last month, Stauber defended the bill from environmental concerns and said mine operation plans must meet current environmental and labor standards. "We have [the National Environmental Policy Act] that we must follow, we have labor standards that we must follow. And when you've met those standards, you ought to be able to move forward," he said then.

Knopf and Lyons both raised concern about the potential economic impact of future mining in the national forest. Because the environmental beauty is tied to the outdoor recreation industry, Knopf said he believes the project would financially harm some by reducing the amount of people who visit.

"People come from all over the world to experience the Boundary Waters, and this risks the current jobs that are dependent upon it," he said.

Star Tribune staff writers Sydney Kashiwagi and Chloe Johnson contributed to this report.