MMIJ Annual Meeting

In deep mining operations, ensuring the safety and stability of operations is vital. This study attempted to estimate the hazards associated with nearby fault slip that cause static deformation and emit seismic waves. Utilizing a 2-D plane strain model and the Finite Element Method (FEM), we evaluated the stress disturbance at the working face due to a nearby reverse faulting, focusing on the static and dynamic effects of the faulting. Our results suggest a significant static change in the vertical stress (σ_z) on the floor as well as the ceiling of the mine. This change in σ_z depends on the distance from the fault and the location relative to the hanging wall and footwall. For both hanging wall and footwall mining scenarios, σ_z at the working face near the fault increased approximately 3 to 4 times when the mining distance was between 120 m and 30 m. To assess the effects of seismic waves, we measured peak horizontal velocity (PHV) and peak horizontal acceleration (PHA) on the ceiling and the floor of the working face. Our analysis indicated that both PHV and PHA were approximately 1.2 times greater on the hanging wall side than on the footwall side. The dominant frequency of the seismic waves, observed to be in the range from 85 Hz to 110 Hz, comes from the characteristics of the seismic source. These results lead us to recommend specialized safety protocols, such as asymmetric support systems near faults, to mitigate the effects of deformation at the working face caused by nearby fault slip and seismic waves emitted from the fault.