| Temporal and spatial variations of mining-induced microseismicity associated with selected stages of a blasthole panel excavation and subsequent post-excavation rockburst sequence, at Strathcona mine, Sudbury, Canada, are investigated in this thesis. The objectives of this study are to relate observed temporal and spatial trends in microseismicity to known geological structures, excavation techniques, and the local/regional stress field, in an attempt to characterize rockburst prone rock masses. This involved discerning trends in: microseismic event locations, their fault-plane solutions, and their source parameters.;Based on the observed spatial and temporal trends in microseismicity, the results could be grouped into general trends in microseismicity and source parameter scaling relations, and into trends directly related to the panel excavation and post-excavation microseismicity. The microseismic events generally located within active mining areas or away from mining next to observed dykelets and late-stage faults, primarily along the footwall-ore contact. An observed temporal migration of microseismicity associated with the rockburst events occurred between areas of active mining; these could be explained by invoking models of stress transfer. The nodal plane orientations for the microseismic events were found to be similar to mapped features associated with ground problems, and could be separated into four sets: an east-west moderately dipping set (late-stage extension fractures), a northwest-southeast moderately dipping set (extension fractures parallel to the dykelets), a northeast-southwest steeply dipping set (late-stage faults); and a northeast-southwest flat-lying set (extension fractures). The nodal planes for the rockburst events were either northeast-trending (late-stage-faults) or were subparallel to the dykelets. The pressure (P), null (B), and tension (T) axes for the microseismic events were compatible with the principal axes of the local stress field (northwest, northeast, and sub-vertical, respectively). The P axes of the rockburst events, however, had a northeast trend, and were compatible with the maximum principal stress axis of the regional stress field. (Abstract shortened by UMI.)... |
