As mines are getting deeper, mining induced seismicity becomes a major hazard threatening the health, safety, and security of operations. In today's mines, seismicity is well measured and documented. However, the ability to foresee events lags behind. This paper will discuss the correlation between numerically simulated Rate of Energy Release (RER) and measured seismic potency in the real rock mass. RER is defined as the rate of elastic strain energy emitted into the surrounding rock as a result of abrupt fracture or deformation. RER has proven to be a good candidate for probabilistic forecasting of seismic potential (the capacity to develop seismogenic activity) in the rock mass. In the following sections, we will describe a computational framework for simulating RER and subsequent analyses for evaluating the likelihood of mining induced seismic events. We will present example results from mines where model predictions matched measured seismicity.
As underground hard rock mines are getting deeper, they are experiencing more seismicity and ground control challenges. Seismicity poses the highest risk to the frontline crew at the mining or excavation face. Whilst improvements in seismic monitoring systems have enabled operations to monitor mining induced seismicity and identify areas with high seismogenic activity, these systems do not have the predictive power to forecast if and when the risk of a high magnitude event is elevated. Therefore, seismicity remains one of the major hazards in mining.
The source of seismicity in mines is very similar to acoustic emissions captured at various stages of the stress-driven failure process during a simple compression test. A seismic event is the sudden release of potential or stored energy in the rock as a result of abrupt deformation or failure. The released energy is then radiated through the rock mass as seismic waves that are captured by seismic monitoring sensors (seismic event). The nature of seismic events depends on physical and mechanical properties of the rock mass and discrete structures.
