A fire in the Soudan underground mine near Tower, Minn., was contained over the weekend, allowing workers to drop into the shaft to assess damage and turn water pumps in the mine's upper levels back on.

Workers also determined that there probably has been no water damage to a $100 million University of Minnesota research lab at the bottom of the mine, 2,341 feet below the surface, said Minnesota Department of Natural Resources spokesman Mark Wurdeman. Elevators sent down to that level Saturday and Sunday morning returned without getting wet, Wurdeman said.

The upper-level pumps remove most of the water that infiltrates the mine, Wurdeman said.

The mine also includes a state park that attracted nearly 38,000 visitors in 2010.

Smoke started billowing from the mine Thursday, and volunteer fire crews from nearby Breitung Township and Tower fought the fire by pouring water and foam retardant down the shaft. Workers from the U and the DNR also were involved.

Workers determined Sunday that the fire burned mostly wood material cast off over the years, Wurdeman said. The cause of the fire is not known.

BILL MCAuliffe