Ely-based Duluth Metals has signed a partnership with international copper mining company Antofagasta to help pave the way for an underground copper nickel project.
The deal comes with $130 million for a feasibility study. Duluth Metals President Henry Sandri called the finalized agreement an exciting step.
"It's taken a long time but we're very glad, and then Antofagasta is a very good partner, he said. "They've got an excellent world wide reputation, and we hope to bring a bunch of that into Minnesota as well."
A three-year study could be followed by an environmental impact statement and mining permits.
The company's underground mining plans are a concern to some who worry about acidic runoff that could pollute rivers flowing north into the Boundary Waters Canoe Area Wilderness.