Gold-bearing zones in the Virginiatown camp area commonly occur as repetitive tabular lenses within veined green carbonate rock and pyritic cherty mudstones. In the carbonates, erratic and often coarse gold in native form occurs in contained quartz veining and is locally referred to as “green carbonate ore”. In the cherty mudstones, gold generally occurs in crystal intergrowth with disseminated pyrite and is locally referred to as “flow ore”. There are other deposit types such as graphite-rich and within altered albitite dikes but these are minor and local.

Brecciated stockwork zones of green carbonate rock also constitute an important deposit type in the area. In these, native gold occurs at quartz vein contacts and is particularly strongly associated with flat or low angle veining. Typically, such zones on the adjoining Kerr Addison mine property could be up to 100 ft in thickness and several hundred feet in length and vertical extent.

Because of the erratic distribution of gold within them, the stockwork zones are very difficult to identify, and were often recognized in drilling at the Kerr Addison mine by the presence of 20 to 30 percent vein quartz carrying a few flecks of native gold. They were generally mined on a bulk shrinkage basis. The only well identified occurrence of this style of mineralization at the McGarry Project is on the 2250 Level in the gold zone encountered in the 600W cross-cut in the 260N Zone.

An important deposit t ........

Shrinkage and longhole mining, and a hybrid combination of these methods, are applicable to this project.

In shrinkage stoping, the ore is mined out in successive flat slices, working upward from the level. After each slice is blasted down, enough broken ore is drawn off from below to provide a working space between the top of the pile of broken ore (“muck”) and the back of the stope. Usually about 40% of the broken ore will have been drawn off when the stope has been mined to the top. After the stope has been mined to the top, the remaining 60% of the ore in the stope is drawn down until the stope is empty. Shrinkage stoping is a method often applied to the mining of narrow veins and has been widely used in the Abitibi gold district. There are variations on the method of access to the top of the stope, to the method of drawing off the broken ore and to the drill/blast techniques for bringing down each successive slice of ore.

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