Twin Metals Minnesota (TMM) is seeking approval build the state’s first underground mining operation in 50 years, near a wilderness area that the Obama-era tried to take off bounds for mining.

TMM, which is owned by Chile’s Antofagasta, on Wednesday formally submitted its project proposal for a $1.7-billion copper, nickel and platinum mine state and federal agencies for approval.

The submittal includes a mine plan of operations issued to the US Bureau of Land Management and a scoping environmental assessment worksheet data submittal issued to the Minnesota Department of Natural Resources.

The site is in an area of the Superior National Forest designated for mining and logging within the US Forest Service Superior National Forest plan. The project is outside of the Boundary Waters Canoe Area Wilderness and the federal and state mining exclusion zones meant to provide a buffer from mining development.

Before leaving office, Barack Obama moved to take about 95 000 ha in the Superior National Forest off the table for exploration and other activities while a study was conducted on the environmental impact. The withdrawal requested a 20-year ban on industry activity, with a two-year moratorium to conduct the study, in a bid to protect water quality and wildlife in the wilderness. President Donald Trump overturned that and opened up the remote area to mining.

Environmental groups argue that a mine could not be allowed to operate in the pristine nature area. Three federally threatened species – the Canada lynx, gray wolf, and northern long-eared bat – live there.

"I truly believe the Twin Metals project will be a model for modern, sustainable and environmentally responsible underground mining," said TMM CEO Kelly Osborne.

Submission of the project starts a multi-year scoping and environmental review process that will thoroughly evaluate this proposal. The review process will include additional baseline data collection, impact analyses, and multiple opportunities for public input.

TMM, to date, invested more than $450-million and is expected to amount to about $1.7-billion through construction of the mine.

The construction phase of the project will require several million labour hours under a project labuor agreement already in place with the Iron Range Building and Construction Trades Council.

Once the mine is operational, it will bring more than 700 new full-time, skilled positions and 1 400 spinoff jobs to the region.

TMM is proposing to mine 2 000 t/d of mineralised ore. Mining operations would occur between 400 ft and 4 500 ft below the surface.