title of the thesis - Department of Geology - Queen's University

The 7200 Level (Fig. D17) is an excellent example of how stress is modelled to be bounded and
channelled between faults. To the north of the excavation, high stresses are concentrated between
the Northwest and Fresh Air Raise Shear Zones, and bounded to the south by the Footwall Shear
Zone. High stress is modelled between the Return Air Raise and Plum Shear Zones to the south
of the excavation and is bounded to the north by the Footwall Shear Zone. This area corresponds
to dense seismic activity.
The 7400 Level (Fig. D18) model shows that high stress forms a ring around the excavation and
is bounded by faults, lowering stress to the southwest of the excavation. NE-striking faults act to
shield this area from high stress. Shear zones in this model act as a boundary to stress rather than
a conduit or concentrator for stress.
The 7530 Level model (Fig. D19) has similar excavation geometry as the 7400 Level and has a
similar stress distribution. Stress is diminished in the southwest, as highlighted best in the elastic
case (Fig. D19A, B) and is elevated in a ring around the excavation, as highlighted in the plastic
case (Fig. D19C, D). High stress occurs between the Plum and Return Air Raise Shear Zones.
Seismicity on this level occurs between the Plum and 402 Shear Zones and thus may not be
accurately represented by the 7530 Level model.
Damage domains are identified in Figure D20. The yield zone, damage zone and intact rock
correspond to those modelled in UDEC.
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