ABSTRACT
The purpose of this research is to use back analysis for mine waste dump slope stability and to determine the causes of the landslides that occured. The research method that we use is the Limit Equilibrium Method and Probabilistic Analysis with the help of the Rocscience SLIDE2 application. In this case study, it can be seen that the slope has a 1.299 static FoS (Factor of Safety) value. This value is categorized into the safety condition FoS category on slope stability if we referring to FoS classification i.e from Read and Stacey (2009). However, in fact the land- slide occur on the slope itself even has a safety FoS category. Therefore probabilistic analysis was carried out to to be follow up with back analysis for the mine waste dump slope in this case study. In the back analysis of the waste dump slope it is assumed the landslide will occur if the FoS value is 1. From the probabilistic analysis, it is found that the closest possibility for the slope landslide failure is when the cohesion and unit weight of the materials decrease to 88.97 kPa and 24 kN/m3. This shows that the amount of water pressure from the recharge area that supply the slope body can reduce the strength and the slope factor of safety. The material cohesion (c) is reduced by 9.54 % and increase the material unit weight value by 3.52 %.
