ABSTRACT
The main coal seam of DAYUAN coal mine in Shanxi province is NO. 2 coal seam, which has an average thickness of 6.5 m, the angle of coal seam is between 40°∼55°, and the average angle is 47°. The immediate roof is light gray/gray mudstone or sandy mudstone with a thickness of 0.1 m∼1.5 m. The main roof is gray siltstone with a thickness of 8 m, the immediate floor is siltstone with a thickness of 2.0 m∼2.6 m. The main roof is composed of gray medium-grained sandstone with a thickness of 12 m, and some parts of it are composed of grit stone and the cementation degree is not uniform. Specifically, most parts are rigid, some loose structures exist in a few area.
