Homestake Mine and Underground Physics Lab, South Dakota

Homestake is a mining area around Lead, South Dakota, a series of underground and surface gold mines that have been active for 125 years. Most of the area’s mines are closed now. One of the mines was turned into a neutrino observatory in 1965, and operated for a few decades. The 1.1-mile-deep mine shaft was selected to avoid interference from cosmic rays. A tank of perchloroethylene was installed at its bottom to capture neutrinos from the sun. Known as the Davis Experiment, after the scientist Dr. Ray Davis, who built the lab (and later won a Nobel Prize). Initiatives to expand the laboratory facilities in the mine include the Deep Underground Science and Engineering Lab project, which seems to have withered recently after NSF funds diminished. The Sanford Underground Research Facility forges ahead, mostly state-funded, and has excavated and enlarged the Davis Cavern, building a “research campus” nearly mile underground. On the surface, the Yates shaft is one of the principal portals to the underground. One recent research inititive involves the Large Underground Xenon experiment (LUX), said to be the most sensitive dark matter detector in the world.