Numerical examination of mining-induced seismicity
Mark Board
Abstract
This paper describes a numerical implementation of the Excess Shear Stress (ESS) approach proposed by Ryder (1987) for providing an engineering estimate of the seismic potential of a rock mass. An approach is presented in which a geologic model of the structure of a rock mass is first developed using standard mapping techniques. A separate numerical analysis is conducted to estimate the mining-induced stress state for a given mining sequence. The stress state at each mining step is superimposed on the fracture model, and the ESS method is used to derive an estimate of the resulting seismic source terms. These source terms are used in comparison to the seismic data base provided by a waveform digitizing system as a means of calibration of the model. Once validated, the model can be used for relative comparisons of various methods or stope sequencing for mining a block of ground. An example application for examination of seismicity at the Lucky Friday Mine, Idaho, USA, is presented.