Soudan Mine Park Closed For Fire Investigation

MINNEAPOLIS (AP) -- An unusual state park created out of a deep underground iron mine to help preserve Minnesota's mining history will remain closed to visitors indefinitely following a fire that broke out late last week.

The Minnesota Department of Natural Resources, which operates the park, thinks the fire is out at the Soudan Underground Mine but won't officially declare that until crews pinpoint where it started to confirm nothing is still smoldering, DNR spokeswoman Amy Barrett said. Crews that went down into the mine Tuesday encountered no smoke, carbon monoxide or other signs the fire was still burning, she said.

Barrett also said it's still too early to know when the half-mile-deep mine near the northern Minnesota town of Tower will reopen for public tours.

"We are really unable and unwilling to speculate because we need to do a very thorough safety inspection," she said.

That inspection, or what might be a series of inspections, can't begin until after crews pump out all the firefighting foam that was poured down the main shaft and get a look at the damage, she said.

"We're so grateful there were no injuries," she said. "We're only looking at property damage and for an incident involving a mine, that's good news."

The park counted 36,707 visitors in 2010, the vast majority of whom took one of the 1,823 group tours offered last year of the mine and lab. While most of the park is underground, it has some above-ground trails and provides access to Lake Vermilion. It's adjacent to the new Lake Vermilion State Park, which is still in the very early stages of development.

The mine is also home to a particle physics laboratory run by the University of Minnesota, which takes advantage of the extremely low levels of cosmic radiation there thanks to the hard rock shielding. Detectors installed a half-mile below the surface are looking for neutrinos beamed through the earth from Fermilab, near Chicago. The lab is also trying to find "WIMPs," or weakly interacting massive particles, which are predicted by theory but have not yet been observed. Scientists say they might make up a large part of the elusive "dark matter" believed to make up most of the matter in the universe.

The fire was detected Thursday night in timbers lining the mine's main elevator shaft. Nobody was inside at the time, and the cause hasn't been determined. Officials don't think the physics lab was damaged.

Park manager Jim Essig and lab supervisor Bill Miller did not immediately return phone calls Tuesday.

Barrett said Tuesday's goal was to try to re-establish power on the mine's bottom 27th level, where the lab is located, to get the water pumps there running again and continue knocking down the foam there, which may allow officials to get a look at the interior of the lab and assess its condition. Sump pumps on levels 12 and 22 were restarted Sunday.

The Soudan Mine was Minnesota's first and deepest iron mine. Dug into the Vermilion Iron Range, it produced more than 15.5 million tons of mostly high grade ore from 1884 until it closed in 1962. United States Steel Corp. then donated the 1,200-acre site to the state, and it became a park in 1965.

Barrett stressed that the DNR expects to reopen the mine for tours as soon as it safely can.

"We're committed to offering tours again," she said. "They're very popular, and we hope to be back in business as soon as possible. We just can't speculate on when that might be."

(© Copyright 2011 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)