A fire in the shaft of an old mine threatens the sole U.S. underground laboratory.
Smoke detectors went off at 9 p.m. Thursday at the Soudan Underground Mine State Park in northern Minnesota, signaling what appears to be a fire in the timbers lining the shaft. The park is home to the Soudan Underground Laboratory, a 36,000 cubic meter facility that houses half a dozen physics experiments including one  that uses a detector weighing 5400 metric tons to study neutrinos fired through the earth from the Fermi National Accelerator Laboratory 730 kilometers away in Batavia, Illinois.
The fire is burning between the mine's 23rd and 25th levels, between 610 and 660 meters underground. The lab lies on the 27th level, about 710 meters underground. Officials with Minnesota's Department of Natural Resources (DNR) are considering temporarily sealing the shaft to try to starve the fire of oxygen, says Marvin Marshak, director of the lab and a physicist at the University of Minnesota, Twin Cities, which runs the lab.
"The most important thing is that there was nobody down there and there's nobody injured," Marshak says. Scientists and technicians periodically visit the lab to attend to the experiments.
Marshak says that the lab is not in immediate danger. However, DNR officials are still trying to figure out how to fight the fire, he says. Ominously, a DNR press release  says "property damage inside the mine is anticipated to be extensive."
The greatest threat to the lab would come not from flames, which should travel up the shaft, but from water rising from the ground. Power to the lab was cut off when the alarms went off, in accordance with emergency procedures. Unfortunately, that also shuttered the pumps that pump the water away. "It's a matter of days or weeks before we would have such a problem," Marshak says. "I fully expect this to be resolved [before then]."