More groups are suing the U.S. Department of the Interior, claiming its decision to reinstate Twin Metals' mineral leases was unlawful.

In two separate lawsuits filed Monday - the Friends of the Boundary Waters Wilderness in one lawsuit and the Center for Biological Diversity, Izaak Walton League of America and Wilderness Society in the other - the groups contend the department did not have the authority to reinstate the copper-nickel mining company's mineral leases and that the proposed underground copper mine poses risks to the Boundary Waters Canoe Area Wilderness.

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In early May, Twin Metals won back federal mineral leases previously withheld by the Obama administration. The leases cover areas at and around the proposed mine site along the Kawishiwi River and Birch Lake just outside and upstream from the BWCAW.

"The federal government is flip-flopping in a way that it does not have power to do," Chris

Knopf, Executive Director of Friends of the Boundary Waters Wilderness, said in a news release.

Scott Kovarovics, Executive Director of the Izaak Walton League, echoed that statement in a separate release.

"The natural resources in and around the Boundary Waters are too important to put at risk from sulfide mining," Kovarovics said. "The Department of Interior has just amplified that risk by arbitrarily reversing its previous decision not to renew Twin Metals' mineral leases."

Although separate lawsuits, the group of plaintiffs coordinated the filling.

Last week, nine northern Minnesota businesses filed a lawsuit against the Department of the Interior over its decision to reinstate Twin Metals mineral leases. The businesses, mostly canoe outfitters, claimed the proposed copper-nickel mine would hurt their business by polluting the nearby BWCAW.

In an email, Twin Metals spokesman Bob McFarlin said the company will use same statement issued after last week's lawsuit.

"Twin Metals is reviewing the complaints filed earlier today challenging the federal government's reinstatement of Twin Metals' leases in the Superior National Forest," McFarlin said. "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 series of lawsuits follows the delivery of three letters signed by more than 170 businesses and outdoor groups opposing the reinstatement of the expired mineral leases and the mining company's updated plans to build a concentrator and processing plant - the operation's major above-ground feature - closer to its mine site. The copper-nickel concentrate produced there would then be shipped to smelters in other regions, likely Canada or the western U.S.

Twin Metals is a wholly owned subsidiary of Chile-based Antofagasta.