With all of this previous activity, CMC has established mine access portals, level development, raises and underground infrastructure that, in most cases, can be utilized for future operations. The proposed CMC restart considers utilizing existing mine infrastructure, access portals, rail transfer levels, ramps, and ancillary mine systems to produce approximately 550 tpd (198,000 tonnes per year) from underground mining. Multiple veins will be mined at the same time and sequenced to maximize value. A ramp-up period will be needed since existing access levels can be rehabilitated to allow for stope development.
Due to the geometry of the mineralized zones, highly selective mining methods must be used for all veins at CMC. Two mining methods are proposed, both as variants of the overhand cut-and-fill (CAF) mining methods. In cases where the vein width is narrower than 0.50 m, resue mining will be used. Resue mining involves selectively blasting and removing mineralized material, prior to blasting waste, to make-up the total minimum mining width of 0.90 m. This mining process is slower and more labor intensive than traditional overhand CAF, but it reduces the amount of waste rock that is shipped to the process plant.
In cases where the vein width is greater than 0.50 m, traditional overhand CAF mining will be used with waste rock as the backfill. In both cases, production stope dimensions are 50 m high by 60 m along strike. These two methods have been histo ........
