A group of nine Minnesota businesses is suing the Trump administration, asserting irreparable harm from a U.S. Department of Interior decision to reinstate two long-expired mineral leases near the edge of the Boundary Waters Canoe Area Wilderness.

The leases are held by Twin Metals Minnesota, a subsidiary of Chilean conglomerate Antofagasta PLC, on Superior National Forest lands.

“My clients would be repelled by water and noise pollution and other harm to the Boundary Waters,” said Steve Piragis, co-owner of Piragis Northwoods Co. in Ely, in a statement released Thursday by the Campaign to Save the Boundary Waters.

In May, Twin Metals announced that if its copper-nickel proposal is approved, it would install a 100-acre ore-processing facility on the banks of Birch Lake, closer to the Boundary Waters than originally planned.

Twin Metals released a statement to the Star Tribune saying it is reviewing the complaint. “Twin Metals firmly believes there is no basis for a court to disturb the reinstatement of the leases, and will take appropriate steps to defend the government’s actions,” the statement reads.

A Department of Interior spokeswoman referred questions to the Department of Justice, which did not immediately respond to a request for comment.

The litigation is the latest salvo in an increasingly contentious legal and political battle over the fate of hard-rock metals mining in the vicinity of one of Minnesota’s most distinctive natural and recreational destinations.

President Donald Trump endorsed mining in Superior National Forest in a visit to northern Minnesota on Wednesday, saying his administration is taking steps to roll back an Obama administration policy to protect hundreds of thousands of acres in the national forest from mining and other industry.

“America’s rich natural resources, of which your state has a lot, were put under lock and key,” Trump said of the Obama years. But his administration will reverse course, he said: “It is going to happen, I will tell you,” Trump told a rally in Duluth.

U.S. Rep. Tom Emmer, R-Minn., who authored a bill that passed the House to restore mining rights to Superior National Forest, applauded Trump’s comments: “The president’s announcement last night is great news for Minnesota.”

Trump and Emmer see the potential for mining jobs — and with them, the votes of Iron Range residents who have long favored Democrats but helped Trump win the Eighth Congressional District by more than 15 percentage points in 2016.

The lawsuit by the business owners against the U.S. Department of the Interior — filed the day after Trump’s visit — illustrates the increasingly well-organized opposition to the proposed Twin Metals project. Environmental groups are incensed that the proposal would mean ore processing less than a half mile from Birch Lake, which feeds directly into the Boundary Waters.

The metals are contained in sulfide-bearing ore, which creates an acid when exposed to air and water that can leach heavy metals and other contaminants out of rock.

The lawsuit says the plaintiffs “depend on the BWCAW remaining in its undiminished, pure state, and on the Superior National Forest remaining a welcoming place for tourists and recreational users.”

The suit reviews the long history of the mining leases. In 2016, then-chief of the U.S. Forest Service Thomas Tidwell wrote to the Bureau of Land Management, warning of “the inherent potential risk that development of 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.”

Other plaintiffs include Voyageur Outward Bound School, Ely Outfitting Co., Hungry Jack Outfitters, Sawbill Canoe Outfitters, River Point Resort and Outfitting Co., Northstar Canoes, Wenonah Canoe and Women’s Wilderness Discovery. A local conservation group, Northeastern Minnesotans for Wilderness, is also a plaintiff.