The fire was contained during the weekend and there was probably no damage to the University of Minnesota research lab at the bottom of the shaft, nearly a half-mile underground, the Minneapolis Star-Tribune reported.
The fire apparently started Thursday from unknown causes. The mine was one of the state's first iron-ore mines.
Minnesota Department of Natural Resources spokesman Mark Wurdeman said pumps used to keep the shaft free of water were turned back on Sunday. He said elevators sent to the lab level returned dry.
Crews from nearby Breitung Township, the university and the city of Tower, assisted by the DNR, used water and foam retardant to fight the fire.
The mine is part of a state park that attracted nearly 38,000 visitors last year.