In 2014, when she was 56 years old, Peta Barrett took a wild leap. Having recently sold her talent agency, she decided to build a new business around her passion for wilderness exploration, with a focus on creating positive outdoor experiences for women. She and her husband moved north from central Minnesota northeast to Ely, a mining town turned recreational gateway to the 1.1 million-acre Boundary Waters Canoe Area Wilderness.

Barrett says her guide service, Women’s Wilderness Discovery, is thriving, with high demand for canoe excursions, winter camping trips, and other adventures in the Boundary Waters and surrounding Superior National Forest. Hers is one of many northern Minnesota businesses—from B&Bs and breweries to fly-fishing shops and dog-sledding guides—whose success is tied to the Boundary Waters, the nation’s most-visited wilderness area.

It’s a remote territory of exposed bedrock, dense boreal forest, and more than 1,000 lakes so clean that some thirsty paddlers simply dip a cup and drink. Three federally threatened species—the Canada lynx, gray wolf, and northern long-eared bat—live there. Its woods, haunted by the Common Loon’s cry, host 24 species of breeding wood warblers, the highest such diversity anywhere in the world. “It’s a gem of the same ilk as Yellowstone or other national parks,” Barrett says.

But these days, when she’s not in the bush, Barrett is focused on fending off what she sees as an existential threat to her business and the backcountry she loves. Beneath the Boundary Waters lies part of a mineral deposit thought to hold more than 4 billion tons of ores containing copper, nickel, and other metals. Twin Metals Minnesota, a subsidiary of the Chilean conglomerate Antofagasta, wants to mine those minerals in the national forest, on the southern edge of the Boundary Waters.

In May, the U.S. Department of the Interior’s Bureau of Land Management (BLM) renewed a pair of leases held by Twin Metals that the department had canceled in 2016 over environmental concerns. The cancelation was the culmination of a series of Obama-era decisions about the project—aimed at protecting water quality and wildlife in the wilderness—that the Trump administration has overturned. Twin Metals can't start mining until it submits a formal plan and secures state and federal permits, a process that could take several years. But environmental advocates have nonetheless been alarmed to see a proposal that not long ago looked all but dead come rumbling back to life.

Barrett and other opponents say the mine is almost certain to discharge toxic pollution into the Rainy River watershed—which flows through the Boundary Waters and into Minnesota’s Voyageurs National Park and Ontario’s Quetico Provincial Park—and countless connected wetlands, streams, and aquifers. “To think that they can come to the very southern border of the Boundary Waters, within a quarter-mile of our protected wilderness area, and not pollute? That’s a fantasy,” she says. “I live downstream. I work in this watershed. If I can’t drink the water, a canoe-based trip is out of the question—you can’t haul enough water for a week-long trip. My livelihood and our home really depend on this ecosystem remaining healthy.”

Mining has a long history in Minnesota’s iron ranges, but the approach Twin Metals is proposing, known as sulfide mining, hasn’t yet been tried in the state. The method involves crushing huge quantities of rock to extract valuable metals from ore bodies called sulfides. (A nearby project planned by a company called PolyMet has received all the required permits and could begin construction soon, which would make it the state’s first sulfide mine. The Boundary Waters ultimately drains into Hudson Bay; the PolyMet project would be in Lake Superior’s watershed.)

When exposed to air and water, sulfides produce sulfuric acid, which can render lakes and streams too acidic for aquatic life. The acid can also leach harmful heavy metals such as copper, zinc, and lead out of surrounding rock, leaving surface and groundwater unsafe to drink. The U.S. Forest Service estimated in 1998 that as many as 50,000 mines were generating acid mine drainage on land it manages, contaminating 14,000 miles of streams. In Europe, this toxic cocktail continues to leak from some mines built during the Roman Empire.

Proponents of the project say it will produce materials needed for modern technology like automobiles, smart phones, and wind turbines. They’re also counting on the mine to create 700 full-time jobs with solid pay and 1,400 spinoff jobs in a part of the state with relatively high unemployment. But Rob Schultz, executive director of Audubon Minnesota, is skeptical of those figures. “When you talk with people in northern Minnesota, many of them remember a bygone era when their grandparents worked in the mines. They want to go back to that, but it’s not reality,” he says. “The mining operations that will come in are not going to hire thousands of people at good pay. They’re foreign-owned companies that will hire minimal people to run robots that pull this material out of the ground and pollute the water, and those resources are going to leave our country.”

Twin Metals assures Minnesotans that its underground mine will have a minimal footprint on the forest and use improved technology to avoid polluting local lakes and streams. The company “will provide data from extensive testing that demonstrates tailings from the mine would be non-acid generating,” said Twin Metals spokesman David Ulrich in an email.

“The problem is that engineering is never perfect. Leaks always occur."

Others say that’s wishful thinking. “If the engineering is perfect, contaminants can be contained,” says Tom Myers, a consultant who specializes in mining’s impacts on water. “The problem is that engineering is never perfect. Leaks always occur.” A 2012 analysis of 14 copper mines, which represented 89 percent of U.S. copper production, found that all 14 had pipeline spills or other pollution discharges, and 13 of them had water collection or treatment system failures “resulting in significant water quality impacts.” The Twin Metals site is particularly vulnerable, Myers and others say, because its geology lacks calcium carbonate, which—just as it eases heartburn as a main ingredient in antacids—helps to neutralize acid drainage at some other mines. “The Boundary Waters is an extremely sensitive, valuable, and pristine ecosystem, so the ‘acceptable’ risk there should be much lower than at many other locations,” Myers says.

Echoing those worries, the Obama administration in its last days in 2016 put the brakes on the project. In 2012, Twin Metals had applied for a 10-year renewal of the two leases totaling roughly 4,800 acres that it has held since 1966 but has not mined. The company said it had the right to automatically renew them, as it had done twice before. But the Interior Department rejected that claim, asserting that the BLM had the discretion to terminate the leases, and that they couldn’t be renewed without consent from the Forest Service.

After an environmental review, the Forest Service said it would not provide that consent. Sulfide mining “might cause serious and irreplaceable harm to this unique, iconic, and irreplaceable wilderness area,” Thomas Tidwell, then chief of the service, wrote. In addition to the threat of acid mine drainage, the roads and other infrastructure to support a mine would fragment forest habitat for moose, wolves, and other wildlife, and could provide a foothold for invasive species.

Acknowledging those risks, the Obama BLM rejected the lease renewal. At the same time, it announced a two-year moratorium on mineral leasing for 234,000 acres of the Superior National Forest that drain into the Boundary Waters while the Forest Service studied a potential 20-year ban on mining and prospecting in the area. It was, the local Timberjay newspaper reported, “a potentially fatal blow to Twin Metals’ proposal.”

But in one decision after another, the Trump administration has brushed aside its predecessor’s concerns and put the company’s plans back on track. In December, 2017, Interior issued a legal opinion that Twin Metals could renew its leases without BLM discretion, reversing the Obama administration’s position. In May of 2018, the department temporarily reinstated the leases. Four months later, U.S. Agriculture Secretary Sonny Perdue, who oversees the Forest Service, ended the study of the proposed 20-year ban—a study Perdue previously vowed he would let go forward. Then, this past May, the BLM officially renewed the leases for 10 years.

To Schultz, that’s a deeply troubling development. Some 163 bird species breed in the Superior National Forest—a designated Important Bird Area—and a total of 225 regularly occur there. They, like other wildlife, need clean water. People, too, need the Boundary Waters, Schultz says, not only for drinking water, but to quench a profounder thirst. “You can watch the northern lights dance above your head and literally feel like you’re in a different world,” he says. “Your phone’s not going to ring. It’s a magical and incredible experience. We have very few places like this left, and we need to protect and preserve them.”

Activists say the federal government, focused on clearing obstacles from Twin Metals’ path, is failing to acknowledge the high environmental stakes and shutting the public out of the decision-making process. “The way this process has unfolded under the Trump administration is really unconscionable,” says Jeremy Drucker, a senior adviser to the Save the Boundary Waters campaign. “They ignore pretty much anything that’s inconvenient to push this project through.”

The BLM points out that the lease renewal adds stipulations to protect the environment, such as prohibiting open-pit mining and strip mining. Twin Metals also won’t be allowed to disrupt any surface or groundwater flow without Forest Service approval. And the company must gain government approval for its formal plan before it can begin mining.

Twin Metals will also have to withstand ongoing lawsuits filed last year by Barrett, other business owners, and environmental groups that argue the BLM didn’t have the authority to reinstate the leases. The administration also faces legal challenges from the nonprofit groups American Oversight and The Wilderness Society alleging it has violated the Freedom of Information Act by failing to turn over documents about the lease renewal. (Members of Congress and others want to know if it’s coincidence that billionaire Andrónico Luksic, whose family owns Antofagasta, rented a six-bedroom home in Washington, D.C., to Ivanka Trump and Jared Kushner.) And U.S. Rep. Betty McCollum (D-MN) has introduced language into a funding bill for the Interior Department that would prohibit federal agencies from advancing any mining within the Boundary Waters watershed until the Forest Service completes the study Perdue canceled.

If Twin Metals is allowed to move forward, opponents worry it could open the door for other projects that will fundamentally reshape the area’s character, turning the Superior National Forest into an industrial zone. The federal government has already issued 28 prospecting permits in the area, and additional mineral lease applications are under review, Drucker says.

That’s not the vision of the Boundary Waters that Barrett had in mind when she launched her company. She figured she’d run it for a decade or so, then hand the reins to a younger woman and enjoy retirement in the north woods. “I want this to be something that continues beyond me, because I think it has great value,” she says.

Now, with the specter of Twin Metals looming, Barrett’s worried whether guiding in the Boundary Waters has much of a future. Will visitors still be drawn to a wilderness with an asterisk, where roaring machinery competes with the loon's call and the water's quality is no longer a given? After building what they considered their final home in Ely, she and her husband have even discussed retiring at a family farm down near Minneapolis instead. Barrett counts herself lucky to have that option. “But it might mean I’d need to close my doors,” she says. “It’s a sad reality.”