Simulation Of Broadband Seismic Wave Propagation In A Deep Mine in Sudbury Ontario Canada

Abstract:

In an active underground mine, amplitudes and travel times of seismic events are critical parameters that have to be determined at various locations. These parameters are useful to better understand the process of spatial and temporal stress distributions in a mine. In this study, variations of travel time and amplitude of seismic waves derived from the conventional constant velocity models are compared to the ones derived from 3D variable velocity model. The results show a significant variation in seismic energy distribution at the mine due to presence of very strong elastic contrast, and the observed complexity of the propagated seismic waves require the use of a variable velocity model. An active deep mine located in Sudbury Ontario Canada hosted this study. Dense 3D arrays of geophones, which are distributed around ore-bodies, have been monitoring controlled production blasts and microseismic events since the mine has started production. It is shown here that the conventional empirical method used to calculate peak particle velocities and accelerations (PPVs/PPAs), tends to underestimate the intensity of seismic waves in stopes or areas close to blast sites. This could be corrected if a more realistic model was implemented. Comparing the travel time information from recorded events in the past few years showed the temporal changes in the mine velocity model as mining progressed, thus updating the velocity model of the mine is needed if better accuracy of event location is required. In this study, a 2D/3D finite difference modeling method is used.