Chilean firm seals Duluth Metals deal, moves toward mine

Chilean mining giant Antofagasta says it's completed its purchase of Duluth Metals, calling it a "positive next step" toward building a massive underground copper-nickel mine in northeast Minnesota.

Antofagasta and Duluth Metals had been partners in Twin Metals Minnesota, which for the past decade or so has been exploring the Duluth Complex, a rich untapped mineral deposit in northeast Minnesota valued at perhaps $100 billion near Ely and the Boundary Waters Canoe Area Wilderness.

The Duluth Complex remains an attractive geological deposit, and the merged company "will focus on further optimizations of the project and advance the permitting process," Antofagasta CEO Diego Hernandez said in a statement Wednesday.

Twin Metals completed a "pre-feasibility study" in August that predicted 30 years of profits and 850 jobs for the proposed operation. But critics argue a round-the-clock mining operation would harm the region's tourism economy, and threaten the pristine waters of the Boundary Waters with potential water pollution.

Before the $79 million Antofagasta acquisition, Twin Metals had said it was still more than a year away from submitting a specific mine plan to begin the environmental review process.

The proposed PolyMet mining project is much closer to possibly becoming Minnesota's first copper mine. The DNR is expected to release that project's final environmental impact statement this spring.