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Longhole – This method is used where the ore zone is wide and dips fairly steeply. It was the

method used at the SG-1 mine, but it is not selective, and when the entire quartz vein must

be taken and the country rock is heavily sheared, there can be signifi cant dilution, which happened

at SG#1, where the grade dropped to about 0.08 oz/ton before it was shut down. In

the lower area of the Rice Lake Mine, we looked at the 4605-96E a LH stope where the HW

collapsed, fortunately after most of the broken ore had been removed. Although the 96 vein

has been reasonable stable at higher levels, this stope had been opened over a length of 140’

which was probably too great a span. The photo below shows the HW slabs at the brow of the

stope. Lessons learned here will be applied in future stopes to reduce the hydraulic radius on

the HW by leaving pillars, preferably in lower grade ore.

This method is used where the ore zone is wide and dips fairly steeply. It was the..Traps 7