High up in the Inyo Mountains of southern California lies the ghost town of Cerro Gordo. Many abandoned mines are all over the surrounding mountainsides, and we decided to explore the abandoned 9000-foot long Estelle Tunnel. This is the lowest mine on the mountain, and it was dug with the hope of intersecting the vertical ore body that the mines up on top of the mountain in Cerro Gordo were tapping into. Nine thousand feet later, the miners never did find the ore body. A major collapse about a third of the way in prevented us from going further in the mine. The collapse was passable, but we opted not to do it.
http://www.youtube.com/watch?v=l7sOGd_fIxE