The fight over Twin Metals' controversial copper-nickel mine in northeastern Minnesota is heading to a federal appeals court.

The Biden administration canceled Twin Metals' federal mineral rights in January 2022, citing potential damage to the Boundary Waters Canoe Area Wilderness. The company sued to get the rights reinstated, but a federal judge in Washington, D.C., upheld the lease cancellation in September.

Twin Metals Friday appealed that decision to the U.S. Court of Appeals for the D.C. Circuit. "With this move, Twin Metals is defending its long held mineral leases in northeast Minnesota from unlawful federal agency action," the company said in news statement.

Chris Knopf, executive director of Friends of the Boundary Waters Wilderness, said Twin Metals' appeal was expected. "I anticipate the result will be the same, that Twin Metals' unfounded claims will be rejected again."

Twin Metals, a subsidiary of Chilean mining giant Antofagasta, has proposed a mine near Ely. But it would be in the same watershed as the BWCA, a unique, federally protected area.

Environmental groups contend hard-rock mines like Twin Metals' threaten to pollute water with toxic acids and metals.

The Obama administration canceled Twin Metals' federal leases, but the Trump administration renewed them. The Biden administration canceled them again, prompting Twin Metals to sue.

In September, U.S. District Judge Christopher Cooper dismissed the case, agreeing with federal agencies and several intervenor environmental groups that the court did not have jurisdiction to hear some of Twin Metals' arguments.

Almost exactly a year after the mineral rights cancellation, the Biden administration also banned mining for 20 years on 225,000 acres of federal forest land — including the site Twin Metals was going to operate on.

A subsidiary of Twin Metals, Franconia Minerals, late last month received state approval to drill six exploratory boreholes near and around Birch Lake in St. Louis County — all within the watershed of the BWCA.