Underground coal mining in India contributes to a share of 55 Mt production with more than 500 mines in operation. In spite of using the well-established CMRI-ISM Rock Mass Rating (RMRdyn) classification system for roof support design successfully in Indian geo-mining conditions, accidents due to roof fall constitute the major challenge. These failures are generally due to the presence of weak beddings and laminations. Seismic refraction technique (for shallow depth) can be useful in detecting the rock mass conditions. Based on the study a modified rock mass classification system (RMRdyn) was setup by incorporating field P-wave velocity with a view to arrive at a real ground condition of the in situ rock. Rock loads were also determined in the field to develop a relation with RMRdyn. A comparison of rock load estimation by CMRI-ISM RMR, numerical simulation and RMRdyn clearly depicts that the latter approach is more reliable as the results are close to the actual scenario.
Keywords
CMRI-ISM RMR, RMRdyn, P-Wave Velocity, Rock Load, Support Design.
User
Font Size
Information