ABSTRACT:
Microseismicity has been extensively used to monitor rock mass response to stress changes; in particular excavation induced damage at underground mines and engineered structures. A methodology has been developed to extract information on fracturing mode and orientation from existing microseismic catalogues. The interpretation is completed with the analysis of the temporal evolution of the energy content and growth patterns of the yielded volumes. The results from this analysis form the basis for the validation of the Synthetic Rock Mass Model for jointed rock presented in a companion paper by Pierce et al. Particle bond breaks in PFC3D are clustered into synthetic microseismic events following size and spacing criteria in order to simulate the activity recorded by a typical seismic array. The method to characterise the seismicity recorded in-situ is also applied to the clustered PFC3D bond breaks. The validity of the approach will be demonstrated by the good correlation found between the fracturing orientation and modes predicted by the model and those observed from in-situ recorded microseismicity. This combined approach can provide a robust method for understanding the factors controlling the behaviour and damage development within a jointed rock mass subject to different stress paths.
1 INTRODUCTION
Block cave mining is an effective method for the exploitation of large underground orebodies with relatively low grade. At present, this method is extending to deeper bodies, for which it is impossible to obtain representative samples for laboratory testing in order to understand the critical factors controlling the fracturing process. The development and testing of Synthetic Rock Mass (SRM) samples in PFC3D provides a unique method to simulate the stress conditions undergone by the rock mass under the conditions typical of deep block caved orebodies.
