According to Mining News Pro - Antofagasta Plc said it had submitted a formal mine operation plan (MPO) to US federal and state permitting agencies but expected to wait several years for a decision.

Twin Metal’s proposed underground mine in Minnesota would border the Boundary Waters Canoe Area Wilderness and Superior National Forest but in 2016 the Obama administration announced a moratorium on new projects.

Environmental groups said mining in the area posed a risk to gray wolves, black bears, and moose and a variety of fish while the neighbouring Canadian government raised concerns about water quality.

The US government announced last September that the Forest Service would cancel the ban on mining in the area. The company said then that it hoped to produce 20,000 tons of mineralized ore per day in order to extract “metals of strategic importance to the US economy and national defense.”

Antofagasta expects the mine to create 700 jobs and also employ 1,400 contractors once operational.