Seismicity and stress changes subsequent to destress blasting at the galena mine and implications for stress control strategies. Report of investigations/1993

Destress blasting is commonly used as a stress control technique at the Galena Mine, Wallace, Idaho, where the U.S. Bureau of Mines maintains a cooperative research program with the mine operators (ASARCO). 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 destressing. Fault plane solutions and dislocation models established that stress changes induced by the event at 034500 PST on February 7, may have been significant in promoting the occurrence of the event at 122020 PST the same day. Theoretical investigations suggest that destress effectiveness can be improved by applying knowledge of the existing stress field, an understanding of rock burst mechanics, and fracture mechanics principles to the design of the destress.