A conceptual protocol for integrating multiple parameters for risk assessment due to induced seismicity in a deep mine

Typically, the time-dependent b-value has been shown to decrease prior to the occurrence of a higher-magnitude event, thus providing a possible indicator of the timing of a significant event. The Energy Index relates seismic energy to seismic moment and an increase in the Energy Index has been associated with an increase in rock mass stress levels. The distribution of P-wave velocity also indicates rock mass stress levels and is provided from time-lapse passive seismic tomography. Finally, prior studies have correlated an increased production rate (blast rate) to higher stress concentrations, potentially triggering a seismic event. Therefore, Energy Index, P-wave velocity, and blast rate may be correlated to stress levels within the rock mass and may imply the magnitude and timing of an event. In this case study, these parameters are used in a back analysis to define a safety protocol for a deep, narrow-vein, underground mine. A catalog of b-value, Energy Index, P-wave velocity, and mine excavation blasting rate, was developed and integrated as a concept of hazardous thresholds. The combination of these various parameters can be helpful in determining the potential for high-risk times and locations due to induced stress.