Mountain Pass Mine
CountryUSA
RegionCalifornia
Year Opened1952
Size/DepthVarious
MineralRare Earths
About Mountain Pass Mine
The only major rare earth mine in the United States. Discovered in 1949 through prospecting for radioactive minerals. Mining began in the 1950s. Supplied most of the world rare earths through the 1990s. Closed in 2002 when prices collapsed, then reopened in 2017. Its ore is rich in neodymium and other magnet metals.