Slope stability assessment and its effect on pit design at Kaolin mine, Ranong province, Thailand

Abstract

This thesis presents a slope stability analysis by a numerical method. Several slope models are established and analyzed with the finite difference software (FLAC3D). In the step of slope stability analysis, some important factors are required to complete the modeling such as geomaterials properties and the dimension as well as shape of slope. To discover the geomaterials properties, geotechnical laboratory testing has been performed on several samples. However, it is quite difficult to test such weathered rock properly. The strength of materials in the study area is quite highly varied, cohesion changing from 13.7 to 178.1 kPa and the frictional angle from 3 to 57.6 deg. For comparison, three (3) different configurations of pit slopes have been designed and analyzed with various face slope angle and overall slope angle. After intensive analysis, Pit Ver. 1 with bench height 4 metres, slope angle 40 deg. and overall slope angle of 28 deg. is the most appropriate to be recommended for final pit design of Sub-Pit MF-10. Even though it gives the lowest reserve for mining but it guarantees the safety for both short and long term mining operations. However, there is still another important aspect need to be studied further which is the effect of erosional process on the pit slope stability. This effect is quite obvious on other pits in the mine.