ABSTRACT
The working face 120207 of Yangchangwan mine exploits coal seam 2# which is 7.3 m thick, 10° incline, and 570 m from the ground. The friable immediate roof of working face is a layer of 0.4 m thick carbon mudstone. Above the immediate roof is a 2.6 m thick layer of siltstone and a 1.6 m thick layer of fine sandstone. The main roof is 17.2 m thick sandstone, and the floor is 2.1 m thick sandy mudstone.
