Identifying a migrating stress front using apparent stress for an unplanned rock mass cave

Throughout a mining environment, variations in geotechnical and stress conditions can lead to unplanned rock mass failure. For operations with microseismic monitoring capabilities, seismic event locations and source parameters can often provide significant insight into rock mass failure processes. This paper presents observed variations in the seismic source parameter, apparent stress, during an unplanned rock mass cave in a deep Canadian mine. Over the course of six months, the rock mass cave propagates upwards more than 75 m, at more than 1,000 m depth below surface. Emphasis is placed on identifying zones of relatively high rock mass stress as the cave propagates upwards over time.