ABSTRACT
The No. 3101 long-wall fully-mechanized working face with large mining height is the first mining face in Chahasu coal mine, its buried depth is 398.8 m and the thickness is 6.45 m. Structures in zonation are simple and dip angle of coal seam is 1∼3°. The roof rock was composed of mudstones, sandymudstones and medium grain sandstones. Among them, the medium grain sandstone is the main roof and its thickness is about 12.55∼24.85 m. The immediate floor of coal seam is carbon mudstone with a thickness of 0.85∼1.8 m, the main floor is consisted of coarse-grained sandstones and its thickness is 5.35-14.18 m.
