ABSTRACT
The paper takes the mine in Shigou Area of WangJiaShan as the research background (Zhang 2007). There are two main coal seams with dip angle of 51°. One of them is about 3∼16.7 m thick in No.2 seam, the other is 10 ∼ 23 m thick in No.4 seam. The direct roof consists of gray and dark gray mudstone and siltstone, which is 8 m thick. Under the roof, there is a soft roof with a thickness of 0.5 m consisting of carbonaceous mudstone. It is easily to collapse for the soft roof. The basic roof consists of gray or off-white medium-sized sandstone, which is more than 25 m thick. The direct bottom with 0.8 m thick consists of the dark gray mudstone. The basic bottom consists of the off-white grit stone, which is 18 m thick.
