Holt-Dern process
Silver and gold refining method / From Wikipedia, the free encyclopedia
The Holt-Dern process is a method by which silver and gold can be extracted from low-grade ores.[1]
The method was applied in mining at Park City, Utah, and in the Tintic Mining District at the Tintic Smelter Site. It was named for George Dern and T.P. Holt.