Characteristics of Mining-Induced Seismicity and Rock Bursting in a Deep Hard-Rock Mine

摘要

Over a recent 20-month observation period, seismogram records were obtained from a single vertical-component short-period seismometer installed at the surface of a metal mine in the Coeur d'Alene mining district of northern Idaho. The seismic events were analyzed for magnitude, time of occurrence, location, and relation to rock bursting and production blasting. Approximately 150 seismic events with local magnitude (M) ranging from -0.5 to 2.9 were located within the mine, yielding a b-value (slope of the logarithm of the number of events with magnitude greater than M versus M) of 0.5. Event locations were constrained using a dense underground array of high-frequency accelerometers. Twenty of the surface-recorded events, with magnitudes ranging from +0.5 to 2.9, were associated with rock bursts that produced damage requiring at least one-half day of clean up and/or repair. Other possibly hazardous rock bursts, with magnitudes as small as -1.1, were numerous, especially at the working face, but were not associated with significant structural damage.