BABBITT, Minn. — Swiss-based global commodities giant Glencore AG says it's taking a 72% stake in PolyMet Mining, gaining majority control over what's slated to become Minnesota's first copper-nickel mine.

PolyMet announced Thursday that Glencore's stake will rise from 29 percent after the completion of a stock offering to shareholders that cleared its balance sheet of debt. Glencore has long been the largest investor in the planned open-pit mine near Babbitt in northeastern Minnesota.

PolyMet is formally based in Toronto but is run from St. Paul with operational headquarters at the processing plant site near Hoyt Lakes. The company received the last federal permit it needed in March, after securing its state permits last year, and is now raising close to $1 billion in construction financing.

Environmental groups are challenging the project in court.