Excavation begins at 4850 Level
Lead, S.D. -- The first blast in nearly eight years at the former Homestake gold mine was detonated at 4:30 p.m. on Sept. 23 in a tunnel 4,850 feet underground. "I never thought a pile of rock could look so beautiful," Sanford Laboratory Engineering Project Manager Willy McElroy said after the blast. "It's a huge milestone for the lab."
Mining ended at Homestake in 2001. Now the South Dakota Science and Technology Authority is reopening the mine as Sanford Underground Science and Engineering Laboratory. Underground labs protect sensitive physics experiments from background cosmic radiation, and Homestake is 8,000 feet deep. The first experiments in the Sanford Lab will be at the 4,850-foot level.
One of those experiments will try to detect an elusive substance called "dark matter." The Large Underground Xenon detector, or LUX, will be assembled in a large chamber excavated in 1965 for a solar neutrino detector that led to a Nobel Prize for nuclear chemist Ray Davis. This summer Sanford Lab technicians removed the steel from the Davis Cavern. Now they'll drive a new access tunnel to the cavern and excavate another smaller cavern for yet another neutrino experiment.
Sanford Lab technicians, many of them former Homestake miners, drilled nine holes for Wednesday's blast. They filled the holes with an explosive made of ammonia nitrate and fuel oil. The precision blast, which yielded 15 to 20 tons of rock, was the first step toward reopening the Davis Cavern for LUX. "It went very well," McElroy said. "Our goal is to create a very smooth surface."
Researchers working on the LUX experiment are eager to move in. "All the members of the LUX Collaboration are extremely excited that the Sanford Lab has reached another auspicious milestone," Dr. Rick Gaitskell of Brown University said. "The creation of the new underground lab is proceeding with great speed and efficiency. We are looking forward to doing science in the new lab in 2010." Gaitskell's colleague, Dr. Tom Shutt of Case Western Reserve University said simply: "One small blast for man, one big bang for mankind."
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