RE:Arizona Silver Exploration may have found boiling zoneThis is the historical info from past mining. It was closed because of WW II and not for economic reasons although I suspect it was not a big money maker at the end looking at $20 oz for gold and $.50 oz for silver. At todays prices and if Beryllium can be economiclly added to the mined ore, Philadelphia has the potential to become a producer again.
Excerpts from the news release.
The mine operated intermittently until 1941 when it was closed by the War Order Act, which closed all non-essential mines in the US in order to focus resources on supporting the World War II effort. The mine reportedly produced about 35 gallons per minute of water, and flooded to approximately the 100 level during the shut-down in the 1940s. It has never been dewatered.
Production records are inconsistent, but the mine apparently produced between 50,000-75,000 tons at an average grade of 0.3-0.79 opt (10-27 gpt) Au. Silver production grades were not recorded, but more recent but still historical sampling in the Philadelphia#2 shaft demonstrates an average grade of 12.25 opt (420 gpt) Ag accompanying an average gold grade of 0.341 opt (11.69 gpt) Au, for a combined gold equivalent grade of 0.485 opt (16.63 gpt) Au(eq). Historical production grades may be in gold equivalents, as they were reported in USD/ton when the gold price was US$20/ounce and silver price was US$0.50/ounce.