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

Both of these inferred stress directions differ from the current stress tensor in which the maximum
principal stress is oriented E-W and the minimal principal stress is near-vertical (Cochrane, 1991;
Coulson, 1996; Malek et al., 2008). According to Anderson (1951), this configuration of
maximum principal stresses should produce reverse faults. In the absence of high pore fluid
pressure, it is unlikely that the steeply-dipping SW-striking shear zones in Creighton Mine could
be reactivated in a reverse sense (Sibson, 1988).
The medium and intermediate stresses at Creighton Mine are similar in magnitude (Coulson,
1996). Inversion of the intermediate and minimum stresses would favor strike slip failure, which
is possible if faults are in a state of critical stability, as proposed by McKinnon (2006). Mininginduced
perturbations to the regional stress tensor are likely to produce either extensional failures
via reduction of normal force on shear zones (unclamping) incurred by rock extraction or stressinduced
strike-slip faulting. Failure mechanisms are explored through microseismic analysis
presented in the Chapter 3.
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