RE: RE: They Must Have Heard Me Reference to the extract from the Metanor Report below, indicates that it is likely that the present gold output has been extracted from narrow veins, which will eventually account for only 10% of total production when the “very productive long hole stoping method” can be brought into production in the Main and B structures.
Metanor Environmental & Social Impact Report (page 23)
Core sample recovery (and the resulting RQD3 estimate) is generally excellent, which confirms that the rock is competent. Considering all these parameters, the following two stoping methods are proposed for mining of the 900,000 t of the Bachelor Lake Mine:
• a conventional long hole stoping method, modified with internal pillars (applicable to about 90% of the sites);
• shrinkage stoping method (10% of the sites).
The very productive long hole stoping method allows better dilution control and results in lower unit costs. Internal pillars can be left in some sectors where the rock is less competent or the gold content is poorer.
To limit dilution, additional support in the form of anchor cables may be installed between the site pillars and in the sublevel galleries, on the roof side (wide wall of the formation above). The method also offers other advantages, such as development of large-scale sites and ore recovery in sectors where there are more geomechanical constraints.
The second stoping method, shrinkage stoping, may be used in sectors where the ore veins are very narrow, typically between 1.2 and 1.5 m. However, the ore must have a higher gold content to justify the additional costs.
Each sector will be analyzed according to the geological and geomechanical data, with the aim of choosing the appropriate stoping method. These analyses are not only essential, but required by the Quebec Mining Association (QMA). The ore extraction equipment used will be equipment commonly employed in the mining industry.