Posted by Mark Pat on December 18, 2001 at 21:42:18:
There have been several posts recently in a number of sites regarding the talc mines. The best details we have found on the Warm Springs (Grantham) is the California Division of Mines and Geogology, Special Report 95, titled Talc Deposits of the Southern Death Valley-Kingston Region, California and published in 1968. The original claims in Warm Springs Canyon totaled 60 and by 1959 over 310,000 tons had been mined. Don't know how much was mined later but basically closed due to depleted resource. The report details the underground workings. The Big Talc and Warm Springs #5 portals opened the most extensive deposits. This was by far the largest talc producing group of claims in the area.