Birch Lake and the waters of the BWCA that lie downstream are still at risk from mining, this time from Franconia Minerals. (Bob King for the Star Tribune/The Minnesota Star Tribune)

Opinion editor's note: Editorials represent the opinions of the Star Tribune Editorial Board, which operates independently from the newsroom.

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If copper-nickel mining on federal lands within the Boundary Waters Canoe Area Wilderness (BWCA) headwaters poses an unacceptable threat, then it's too risky to extract these metals from locations in the same fragile watershed.

That's why alarm bells should be going off statewide in the wake of a new exploration plan from a company owned by Chilean mining conglomerate Antofagasta. In late September, Franconia Minerals submitted to state regulators a proposal to drill exploratory holes on areas "scattered between the former Dunka mine, east of Babbitt, and the eastern edge of Bob Bay, a part of Birch Lake, in St. Louis County," the Star Tribune reported recently.

The push by Franconia comes after a serious setback for Antofagasta's proposed underground copper mine on federal lands near Birch Lake, whose waters flow into the BWCA, creating a pathway for pollutants to reach it. In January, the Biden administration declared a 20-year moratorium on this type of mining on about 225,000 acres, a historic step guided by a scientific analysis outlining the risk to this watershed. That inquiry began under former President Barack Obama and was then suspended and its findings kept secret by former President Donald Trump's administration.

In 2019, the Star Tribune Editorial Board special report "Not this mine. Not this location" detailed this type of mining's dubious environmental track record and called for a permanent copper-nickel mining ban within the BWCA's northern Minnesota watershed. Another high-profile Minnesota copper mining venture, PolyMet's NorthMet project, lies outside this watershed.

Mining companies owned by Antofagasta enjoy a significant advantage — access to its deep financial pockets. That apparently has enabled the firms' continued push to mine copper, nickel and other metals elsewhere on the BWCA's doorstep. The drilling exploration plan suggests that Antofagasta and its subsidiaries are simply switching gears to develop nearby resources in the state that are not affected by the new federal moratorium but still lie within the BWCA's headwaters.

That effort could lead to mining underneath Birch Lake, according to an Oct. 9 letter sent to state regulators by the organizations Save the Boundary Waters and Northeastern Minnesotans for Wilderness. The groups oppose copper-nickel mining near the BWCA and are suing to stop it.

Bruce Johnson, a retired Minnesota environmental scientist with extensive experience in sulfide mining, told an editorial writer that mining under the lake poses additional risks. It could be more difficult to track seepage containing potential pollutants from the mine, he said. In addition, there's a risk of collapse.

A spokeswoman for Twin Metals, which owns Franconia, did not answer a question about whether a new mine could go under Birch Lake. The DNR declined to say where the drilling would be because it is a "nonpublic trade secret," but a Twin Metals statement Friday said "targeted areas for the drilling program are not under Birch Lake."

Johnson has noted that there's already difficult-to-control water pollution from a nearby former taconite mine's sulfide-bearing waste rock. "We already know we have a problem on Birch Lake," Johnson stated in the Star Tribune news story. "To explore something we know we can't control ... why drill it?"

Minnesota lawmakers have only themselves to blame for leaving the door wide open for Antofagasta's attempted end run around the federal moratorium. Despite the federal scientific analysis, they have failed to put in place long-term copper-nickel mining protections in other areas draining into the BWCA.

Legislation championed by Sen. Kelly Morrison, DFL-Deephaven, and Rep. Sandra Feist, DFL-New Brighton, during the 2023 session called for permanent state protections but would not have prohibited "existing or future taconite, iron ore, sand, gravel, and granite mining." Unfortunately, the measures gained insufficient traction.

This is a dereliction of duty requiring legislative remedy in 2024. It's also frustrating after the Biden administration's conscientious moratorium. The feds have done the scientific and policy heavy-lifting. Now the state just needs needs to follow their lead.

Higher-profile advocacy on this from Gov. Tim Walz is also imperative. Walz effectively wielded the governor's bully pulpit during the past session to pass the state's historic new child tax credit.

Like that legislation, protecting the BWCA from copper mining pollution is critical for future generations' wellbeing. Until the state acts, Antofagasta and its risky mine regrettably aren't going away.

Editorial Board members are David Banks, Jill Burcum, Scott Gillespie, Denise Johnson, Patricia Lopez, John Rash and D.J. Tice. Star Tribune Opinion staff members Maggie Kelly and Elena Neuzil also contribute, and Star Tribune CEO and Publisher Steve Grove serves as an adviser to the board.