Slope Stability Of Final Highwall Slope At West Bokaro Collieries, India

The paper deals with geotechnical study for the final slope of 140 m high final open pit mine slope at SE Block of West Bokaro Collieries, Tata Steel. It is mainly characterized by sandstone and coal. The bulk density and direct shear tests were conducted at Rock Mechanics Laboratory of CIMFR on the samples collected from the field. The geotechnical mapping was done on the exposed benches of the quarry as per the norms of International Society of Rock Mechanics (ISRM 1978). The kinematic analysis was done to determine the critical orientation of structural discontinuities. After identifying kinematically possible failure modes, detailed slope stability analysis was carried out by GALENA software based on limit equilibrium method. The present study reveals that the 140 m high final slope could be designed with 47 degree overall slope angle. The sensitivity analysis shows that the influence of water is also alarming. It was recommended that the slope should be kept in drained geomining condition by providing suitable drainage and keeping drainage effectively maintained.