Stillwater Mining Company - Processing Mined Material

Processing Mined Material

Stillwater Mining Company is engaged in the development, extraction, processing, refining and marketing of palladium, platinum and associated metals (platinum group metals or PGMs) from a geological formation in the Stillwater igneous complex in south central Montana known as the J-M Reef and from the recycling of spent catalytic converters. The J-M Reef is the only known significant source of platinum group metals inside the United States and one of the significant resources outside South Africa and Russia. Associated by-product metals at the Company’s operations include minor amounts of gold, silver, nickel and copper. The J-M Reef is a narrow but extensive mineralized zone containing PGMs, which has been traced over a strike length of approximately 28 miles (45 km).

The company conducts mining operations at the Stillwater Mine near Nye, Montana and at the East Boulder Mine near Big Timber, Montana. Both mines are located on the J-M Reef. The company operates concentrating plants at each mining operation to upgrade mined production to a concentrate form. The company operates a smelter and base metal refinery at Columbus, Montana at which it further purifies the mined production to a PGM-rich filter cake. The filter cake is shipped to third-party custom refiners for final refining before being sold.

The company recycles spent catalyst material to recover PGMs at the smelter and refinery. The company has a longterm catalyst sourcing agreement and spot contracts with other suppliers who ship spent catalysts to the company for processing to recover PGMs. The company smelts and refines the spent catalysts by the same process as the mined production is purified.