Mining engineers must certify that the capacity of excavations in their mine exceeds the expected demand. This requires the engineer to satisfactorily estimate the expected future loads that an excavation will be subjected to, as well as the capacity of the rock mass—ground support system. In seismically active mines, this essential task is more difficult as high rates of deformation and dynamic loading are still comparatively infrequent events and the simulation of support and reinforcement for dynamic loading is more complex. Empirical methods of estimating excavation capacity for dynamic rock related hazards are also very poorly evolved, and have limited efficacy. In this paper, computational forecasting of potential for dynamic deformation in rock masses surrounding mines as well as the simulation of potential large events themselves is discussed.
When a hard working pillar, or rock bridge in the mine fails, or a highly stressed fault slips, load is redistributed from that yielded ‘structural element’ of the rock mass. Other parts of the mine must do that ‘work’. Whether other components elsewhere in the mine subsequently fail is a function of their capacity and the load path and ultimate loading which evolves as the system converges to a new equilibrium. Subsequent failures are rarely due to impulsive loads or vibrations from the seismic wave emanating from the original failure. Though seismic waves do damage excavations in mines, the magnitude and occurrence of the hazard is less than the exposure of personnel to increasing rock mass damage and deformation due simply to load redistribution caused by mining and under-supporting of excavations.
