The Homestake Mine was a deep underground gold mine located in Lead, South Dakota. Until it closed in 2002 it was the largest and deepest gold mine in North America. The mine produced more than 40 million troy ounces (approximately 1.25 million kilograms) of gold during its lifetime. The Homestake Mine is famous in scientific circles for being the site at which the solar neutrino problem was first discovered. This became known as the Homestake Experiment. The deep underground laboratory was set up by Raymond Davis Jr.