The Cave Mine produced high-grade copper, lead, zinc, silver and gold ores from 1871 to 1900.
Ore deposits occur as chimneys, fissures and mantos, cutting Devonian limestone and dolomite. Mineralization occurs as gossans with base metal oxides, gold and silver.
Few reliable production records exist but there are over 10,000’ of underground workings so production was considerable. From 1878 to 1884, 12,013.5 tons of ore were produced at an average recoverable grade of 0.30 oz/ton gold, 15.65 oz/ton silver, and 15.13% lead, Kramer (1947).
Mining operations were discontinued in the early 1900’s at a depth of 100m at the base of oxidation when sulfide mineralization was encountered that could not be processed in the Frisco smelter. GCSM believes that the sulfide core of the system has never been explored.
Figure 5 shows the generalized geology, underground workings and mined stopes. The down-dip projections of mineralization is the target of GCSM’s exploration work.
At least three holes are planned to test these targets. Intercepts may contain very high grades of Cu, Pb, Zn, Ag and Au in the sulfide zone and particularly in a zone of supergene enrichment at the base of oxidation. Drill holes would be to about 300m but significant mineralization may be encountered at much shallower depth.
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