Southern Operations - The Southern Operation mining engineers design all stopes and development
workings based on current local geological information and ground conditions. Various structural
features, such as the shear zone that forms the contact for much of the Lead lode, the Flat Fault, and
the Main Shear zone have a major influence on the approach chosen for stope design and ground
support. Ground conditions within the mine are quite variable, ranging from more competent
ground in the upper levels to highly stressed and foliated ground in areas such as the Lower 2 lens.
Stope and development design in the Pillars area (see Figure 19-1) is further complicated by the
presence of local structures associated with previously mined stopes, as well as the presence and
quality of backfill in the old stopes. Ground conditions are evaluated through a continuous
program of diamond core logging, visual inspection, geologic mapping of development drives, and
through the use of a micro-seismic monitoring system.