Stillwater PGM Mine, Montana

The Stillwater Mining Company is the only producer of “PGM” in the USA. These are platinum group metals, such as palladium and platinum. The deposit here is known as the J-M Reef, and is one of the rare high-concentrations of the material, which is used in various industrial and consumer products, such as catalytic converters of vehicles. South Africa and Russia are the main sources of this material. The Stillwater company was bought by a South African mining company in 2017 for $2.2 billion. Production started here in 1986. It is an underground operation, with substantial processing facilities and slag areas on the surface, though around half of the tailings are redeposited underground as infill. Another mine owned and operated by Stillwater is at another part of the deposit, at East Boulder. The company operates a processing facility nearby at Columbus.