Feasibility study of dumping area on bearing capacity and slope stability analysis

Open pit mining, especially coal mining, needs cleaning and cutting of overburden. It needs an area for dumping overburden material. This area called disposal or dumping area. We need engineering geological mapping, analysis of bearing capacity, and slope stability analysis for preventing the failure of the dumping area. Therefore, this research aims to identify the best location of dumping area and the design of stable dumping area. Methods that were used in this research are: (1) field engineering geological mapping, soil and rock sampling from either outcrops or three bore holes i.e.: GT01, GT02, and GT03; (2) laboratory analysis method for gaining information about UCS, angle of friction, cohesion, and unit weight, and (3) office method be in the form of analysis of engineering geological map, bearing capacity (Terzhagi’s Formula), and slope stability. Then the design of stable dump could be made according to the result of slope stability analysis. The result shows that value of bearing capacity is different in each borehole. The location that suggested for dumping area is around boreholes GT03 (Engineering Geological Unit of Fine Soil II) because it has highest bearing capacity, among other boreholes, it is about 494.452 t/m²for continuous foundation. The simulation and analysis of slope stability show that safe design of dump is: single slope 25.6º, overall slope 15.5º, and maximum dump height is 50 m.