Antofagasta PLC started the environmental permitting process for its US$1.7 billion Twin Metals copper-nickel-platinum project in Minnesota, Reuters reported.

The London-listed copper miner submitted a formal mine operation plan to federal and state permitting agencies, but expects to wait years before a decision is reached.

The move was made possible following a Trump administration order to reverse a 2016 protection order that halts new projects over the nearby Boundary Waters Canoe Area Wilderness and Superior National Forest. Environmental groups said the operation may pose a risk to endemic wildlife, while the Canadian government raised concerns over water quality.

Meanwhile, a group of Minnesota environmentalists, including former Natural Resources Commissioner Tom Landwehr, are urging Governor Tim Walz to stop the proposal as it would endanger one of the state's greatest assets, the Star Tribune reported Dec. 18.

The Minnesota news outlet's report said Landwehr also called on state regulators to consider the permit application for the Twin Metals project incomplete as it will not include findings of a halted federal study on hard-rock mining within the forest.

The U.S. Forest Service was conducting the study under the Obama administration, but the Trump administration canceled it after the reinstatement of the mining leases held by Antofagasta unit Twin Metals Minnesota LLC.