Mountain Pass rare earth mine. Storage area for waste minerals produced from the refinement and separation of rare earth ores to obtain their oxides. This mine is located in the Clark Mountain Range, California, USA. Operated by Molycorp, it is the only rare earth oxide (REO) mine in the Western hemisphere and the world's largest such mine outside of China. Dominating world trade from the 1960s to the 1980s, it was closed in 2002, with active mining resuming in 2010. These rare earth elements (including praseodymium, neodymium, yttrium, and terbium) are used in a range of high-tech equipment. Photographed in October 2011.