Palladium is a precious metal, one of the platinum group metals (PGM), which typically are found together in ore deposits. The USA has only one primary palladium producer, the Stillwater Mining Company, which operates two mines in southern Montana. At that location, the palladium ore bearing layer called the J-M (Johns-Manville) Reef is the richest known palladium deposit currently being exploited anywhere in the world. Active mining from this location produces a high grade ore containing a palladium:platinum ratio of just over 3:1. After mining, the ore is refined by Stillwater at a site near Columbus, Montana, to a purity of 60% PGMs, then shipped to Johnson Matthey for final refining of palladium, platinum and other metals at a facility in New Jersey.

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The ore from Stillwater Mining’s operations is refined in a 3 stage process of extraction, concentration and refining. Some of the process produces biproducts that can be marketed, among them, copper, nickel and cobalt. In extraction, a crushing and milling process produces a liquid mix from which a concentrate is extracted. Following that, the concentration process dries and smelts the concentrate, and through two processes, separates a “converter matte” with high PGM content from other byproducts. In the final refining process handled by Johnson Matthey, standard electrolyte techniques are followed by separation and purification to produce refined metals.