Correlations between mining and seismicity for re-entry protocol development

Re-entry protocols are a strategic approach for controlling risk after large magnitude events or blasts in seismically active mines by monitoring the return of seismicity to background levels. Restricting access to areas of a mine affected by seismicity for sufficient time to allow this decay to occur is the main approach in most re-entry protocols. In the present study mining and seismicity are correlated for re-entry protocol development by using a uniform statistical technique for the identification of background levels. The relations are established relying on a theoretical framework that links the productivity of seismicity with the decay time of seismic sequences. Three case histories are presented and analyzed, selected to illustrate the possible effects of factors, such as: volume of mined rock, depth, and magnitude of large events, on the decay time of mining-induced seismic sequences. Positive significant correlations between the decay time and the mining factors studied here are found. (C) 2011 Elsevier Ltd. All rights reserved.