Dynamic behaviour of mining-induced fault slip

• Mining depth and the friction angle of a fault significantly affect relative shear displacement increments along the fault.
• The dilation angle and stiffness of a fault do not significantly affect seismic source parameter of fault-slip.
• The maximum slip rates appear to increase with the maximum slip, although their locations do not coincide.
• Extremely high rupture velocity could occur in mining contexts, depending on the positional relationship between faults and stopes.
• Simulating fault-slip with the Mohr Coulomb criterion could underestimate the magnitude of the fault-slip.

Fault slip bursts induced by mining activities could inflict severe damage to nearby mine developments. Considering a variety of factors that might exert an influence on the fault slip, dynamic numerical analyses are conducted for models having a fault parallel to a tabular ore deposit. The results obtained from the analyses show that the maximum dynamic shear displacement increment induced by stope extraction is significantly affected by the friction angle of the fault, as well as mining depth and position of fault with respect to the orebody, while the stiffness and the dilation angle of the fault do not have as much influence. Seismic source parameters are computed based on the numerical results and as is the case with the maximum relative shear displacements, the position and friction angle of the fault appear to have the strongest influence on seismic moment and energy released by fault slip. The limitations of Mohr–Coulomb criterion as applied to the dynamic analysis of fault slip bursts are discussed in light of the results obtained. Lastly, slip rates and rupture velocity are investigated. The results show that the maximum slip rates are associated with the maximum increments of relative dynamic shear displacement. It is shown that extremely high rupture velocity could be induced by stope extraction. This could be the cause for a severe seismic event.