A federal judge in Washington, D.C., heard oral arguments Friday in a lawsuit that could determine the fate of the highly controversial copper-nickel mine that Twin Metals Minnesota wants to build near the Boundary Waters Canoe Area Wilderness.

The project was all but dead in 2016 after the Obama administration denied the company’s request to renew its two federal mineral leases to mine on 5,000 acres of public land in Minnesota’s Superior National Forest. The U.S. Forest Service had objected, with former Chief Thomas Tidwell writing: “A regionally-untested copper-nickel sulfide ore mine within the same watershed as the BWCAW might cause serious and irreparable harm to this unique, iconic, and irreplaceable wilderness area.”

Under President Donald Trump, the two mineral leases were reinstated on the grounds that the language of the long-held leases gave Twin Metals a right to successive renewals. The project was resurrected.

A group of nine Minnesota businesses, including Voyageur Outward Bound School and River Point Resort and Outfitting Co., then sued the U.S. Department of the Interior, as did environmental groups such as the Wilderness Society and Friends of the Boundary Waters Wilderness and Campaign to Save the Boundary Waters.

The three cases were consolidated before U.S. District Judge Trevor McFadden, a Trump appointee, in Washington, D.C.

The litigation is part of an increasingly heated legal and political battle over whether Minnesota should allow the mining of hard-rock metals, which pose greater environmental risks than the longstanding taconite industry, in the watery ecosystems of northeastern Minnesota.

The case before McFadden centers on the terms of the Twin Metals leases, which were first issued in 1966 and renewed twice before.

A Twin Metals spokeswoman said the company doesn’t comment on ongoing litigation. But it has argued that the federal mineral leases were first issued “with a right of unlimited, successive 10-year renewals” and that they’ve been renewed before without controversy. Twin Metals sued the previous Interior Department when it didn’t reinstate the leases, saying it takes so much time and money to develop mining projects that no one would do it without the promise of lease renewals.

Ely resident Becky Rom, national chairwoman of the Campaign to Save the Boundary Waters, attended Friday’s hearing. Rom said a number of additional citizen supporters who live in the Washington, D.C., area also attended, as did members of environmental groups such as the Center for Biological Diversity and the Wilderness Society.

Rom reiterated her group’s position that reinstatement of the leases wasn’t automatic and that the company was supposed to have commenced commercial production by 1986 in order to get renewal rights.

“The outcome of this case will determine whether or not we have a Boundary Waters,” Rom said. “The outcome of this case will determine whether or not the people in the area will still want to live there.”

McFadden is expected to rule within a month. Cancellation of the leases has the potential to stop the Twin Metals project in its tracks.

Twin Metals this week submitted its formal proposal for the $1.7 billion mine to state and federal regulators, launching a permitting process that could take several years. It’s one of two copper-nickel mines, along with a project by PolyMet Mining, proposed for northeastern Minnesota.

Ivanka’s landlord

Jacob Eisenberg, a public lands advocate at the Natural Resources Defense Council (NRDC), which is not a party to the lawsuit, said his group is closely tracking the litigation. He called the dispute “a poster child for the way the Trump administration has managed America’s public lands.”

“It shows a disregard for science, arbitrary decisionmaking, blatant industry favoritism and there’s a hint of corruption here as well.”

Eisenberg was referring to the lobbying efforts of Twin Metals’ parent company Antofagasta in Chile, one of the world’s largest producers of copper. In 2017 the Wall Street Journal first reported that a U.S. real estate company owned by Andrónico Luksic, chairman of the family company that owns Antofasta, bought a $5.5 million Washington, D.C., home and quickly rented it to Ivanka Trump and her husband, White House adviser Jared Kushner. All parties have claimed the timing was a coincidence and the transaction was done at arm’s length, according to the Wall Street Journal.

Eisenberg said he would not be shocked if the Minnesota groups won their fight. He said the NRDC has prevailed in nearly all of its 62 legal challenges to decisions of the current administration that have so far been resolved.