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Seismicity and stress changes subsequent to destress blasting at the Galena Mine and implications for stress control strategies.
Boler FM; Swanson PL
Denver, CO: U.S. Department of the Interior, Bureau of Mines, RI 9448, 1993 Jan; :1-21
The U.S. Bureau of Mines conducts research at the Galena Mine, Wallace, Idaho, with the aim of mitigating the effects of rock bursting. Destress blasting is commonly used as a stress control technique at the mine. A digital seismic array and an array of borehole pressure cells (BPC's) had been installed near the site of a stope undergoing mining and periodic distressing. The instrumentation was being monitored at the time of a distress blast of the 46-99 stope. No significant seismic events occurred coincident with the distress. However, the destress was followed by a 21/2-week period of increased seismic activity, including two damaging events on February 7, 1990, at 034500 (hour, minute, and second) and 122020 Pacific standard time. BPC measurements indicated coseismic ground pressure changes on the order of 200 to 300 kPa associated with the damaging events. Fault plane solutions and dislocation models established that stress changes induced by the event at 034500 may have been significant in promoting the occurrence of the event at 122020. theoretical investigations suggest that applying knowledge of the existing stress field, an understanding of rock burst mechanics, and fracture mechanics principles can improve distress effectiveness.
Mining-industry; Rock-bursts; Rock-falls; Safety-research; Safety-measures; Safety-monitoring; Rock-mechanics; Geology; Miners
Report of Investigations
NTIS Accession No.
Denver, CO: U.S. Department of the Interior, Bureau of Mines, RI 9448
Page last reviewed: November 12, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division