Stability analysis of underground stope pillars using three dimensional numerical modelling techniques

An underground chromite deposit of strike length 290 m, width 20 m and having dip of 10 degrees with horizontal is bounded between the county rock of weathered serpentinite, serpentinite, quartzite and pyroxenite and is planned to be extracted by sub level open stoping method. The portal of the decline and shaft are located in the foot-wall of the orebody. The stope dimensions are to be determined for safe extraction of chromite ore body. For this purpose, three dimensional finite element method is adopted to develop the stope model along with decline and shaft. This study establishes the suitable pillar dimension, length and width of stope and roof bolting based on development of stresses, displacements and yield zone around the excavations.