16 soil samples from the Main Pit areas and 1 soil sample from the West Sub Pit area have been collected and analyzed to determine the mineral composition by x-ray diffraction method. If analysis results indicate the main components of soil is clay mineral species montmorillonite, It will be called "expansive soil or shrink-swell soil", is a very common cause of the foundation problems and slope stabilization, especially when expansive soil has excavated and dumped at the main dump area, it effect to the Main equipment, i.e. Waste conveyor line and the spreaders. Because of the expansive soils are soils that expand when water is added, and shrink when dry out. The Location of soil sampling in the Main Pit and the West Sub Pit are as shown in Figure 1.