The U.S. Forest Service and the U.S. Bureau of Land Management denied the renewal of two long-held federal mining leases of Twin Metals Minnesota LLC in the Iron Range region of Minnesota, according to a Dec. 16 release from parent Antofagasta Plc.

Twin Metals filed the lease renewal application in mid-2013 and is in the early stages of developing a proposal for an underground copper-nickel mining project in the region.

According to the statement, Twin Metals believes the denial of the leases is inconsistent with federal law, given that they have been held in good standing for more than 50 years and have been twice renewed without controversy.

The Antofagasta unit said it is committed to advancing the project and will continue to pursue legal avenues to protect its contractual mineral rights.