A few years ago, I met up with some of the guys and we hiked out to visit the ruins of the old Corkscrew Mine. The mine was worked for colemanite (an ore of borax) in the 1950s by the US Borax Company. Surprisingly, it was productive only for a few years.
The mine has been gated by the NPS and the beautiful ore bin fenced. Please respect this interesting bit of history.