Twin Metals Minnesota on Thursday filed a petition in federal court asking to become a defendant in the three lawsuits filed in recent weeks over its right to mineral leases next to the Boundary Waters Canoe Area Wilderness.

It has a vested interest in the case, according to its legal petition, and wants the opportunity to defend the U.S. Department of the Interior’s decision to reinstate the leases. One lawsuit was filed by nine Ely-area businesses that rely on the wilderness for their revenue, and an advocacy group, Northeastern Minnesotans for Wilderness. The other two were filed by another advocacy organization, the Friends of the Boundary Waters Wilderness, and four national environmental groups. All three complaints are pending in federal court in Washington, D.C.

Twin Metals, a subsidiary of the Chilean mining company Antofagasta, has proposed an underground mine and processing facility next to the BWCA and a mine waste confinement basin just outside the watershed. In addition to a PolyMet Mining Co. plan, it is one of two proposed projects that would launch a new copper-nickel mining industry in northeast Minnesota that proponents say will create hundreds of jobs. But the proposals are highly controversial because copper-nickel mining creates far greater risks to water than taconite mining by producing acid drainage that leaches heavy metals and other contaminants out of rock.

Twin Metals relies on exploratory federal mining leases that it or its predecessors have held since the 1960s, and which were twice renewed by the Interior Department. But when they came up for renewal under the Obama administration in 2014, a concerted effort by environmental and outdoor groups helped persuade the federal agency to deny them. The U.S. Forest Service also declined to sign off on them, citing the significant risks to the ecologically sensitive wilderness from polluted mine runoff.

But last December, an opinion issued under U.S. Interior Secretary Ryan Zinke said that the decision to deny them was legally incorrect, and reversed it. Last month it reinstated the leases, prompting the legal fights.

All three lawsuits claim the federal government does not have the legal authority to reinstate leases, and that the U.S. Forest Service was required to sign off on them, which it didn’t do.

Twin Metals said in a statement that it has invested more than $400 million to date in acquisition, exploration, technical, environmental and other project development activities, and that its project would meet all state and federal environmental standards, and provide hundreds of jobs for generations of Minnesotans.