The conceptual geologic model that best applies to the Commonwealth Silver and Gold Project is a variation of the rift, low sulfidation, epithermal chalcedony-ginguro model of Corbett (Corbett, 2002). The characteristics of this model are mineralogy derived primarily from dilute, near neutral pH fluids, an extensional, dilatant structural setting, competent host rocks that fracture well, and abundant banded chalcedonic quartz.

The mineral deposits within the Commonwealth Project area are typical of silver dominant, low sulfidation, epithermal veins and stockworks emplaced in a near surface environment. The veins are best developed in the andesite to rhyolite units of the Pearce Volcanics. These volcanic rocks fracture well, are densely fractured to shattered, and host dense quartz stockworks, breccia zones and banded quartz veins. Cretaceous marine sediments of the Bisbee Group also host mineralization and are chemically favorable hosts. The calcareous sandstones and siltstones of the Bisbee Group are very similar to the “dirty carbonate” host rocks of many sediment hosted disseminated gold deposits in Nevada and in northern Mexico. These rocks seem to be especially favorable hosts for gold mineralization and there is a higher Au:Ag ratio in the assay results from mineralized Bisbee Group samples as compared to the mineralized volcanic rocks at the Commonwealth Project. The Bisbee Group sediments are soft enough that they do not fracture well on faulting.  Minerali ........

The Commonwealth Project contains mineralization at or near the surface that is ideal for open pit mining methods. The method of material transport evaluated for this study is open pit mining by a mining contractor using two 12.2-m3 front end loaders as the main loading units with a third 12.2-m3 front end loader as a backup loading unit and feeding the mineralized material stockpile when required. The mineralized material will be loaded into 90-tonne haul trucks and transported to the primary jaw crusher, which will be set up at the south end toe of the waste dump. The plan assumes that the contract mining company owns, operates, and maintains all equipment.

Production of mineralized material is planned at a nominal rate of 10,000 tonnes per day (tpd), equivalent to 3.65 million tonnes per annum with an 8.5 year mine life. Mining is planned on a 7 day per week schedule, with two 12 hour shifts per day. Other mining schedules may prove to be more effective, but are not expected to significantly change project economics. Peak mineralized material and waste production is estimated at 33,000 tpd during year five with an average rate of 20,000 tpd. The average life of mine stripping ratio is 1:1 waste-to-ore, using a 0.30 g/t AuEq cutoff. Lower grade material is stockpiled using 0.24 g/t AuEq cutoff in order to improve project economics, which results in a maximum low grade stockpile of 2.4 million tonnes. The stockpile is used to balance the feed of mineralized materi ........

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