... ABSTRACT: The existence of the overlying compound key strata would cause stress distribution in surrounding rock, breaking of the key strata and the periodic weighting of a mining face, which are also related to variation of the mining height. Based on the compound key strata theory...

... seam dip angle is 0 °; the mining height is 6.2 m; the mining face is 240 m in length. The size of rectangular roadway is 5 m x 3.6 m. The three- dimensional grid computing model and the ver- tical stress distribution are shown in Figure 1. 2. Simulation scheme and stopping process. The coal pillar...

.... The results showed that with the increasing of mining height, the scope of abutment pressure is gradually increased, but the peak point pressure is not increased. Compare to the routine mining height workface, the periodic weighting length is shorter and the dynamic factor is bigger. 1 INTRODUCTION...

.... With the development of the large cutting height mining and top-coal caving theory and techniques, as well as the improvement of fully-mechanized equipment, the extremely-thick coal seam is increasingly considered to be mined by top-coal caving with great mining height. And this mining method positively combines...

... ABSTRACT: Because of higher space of mined out area in large mining height stope, and direct roof cannot completely fill the space of mined area, hence, there is a larger space need main roof rotary deformation, violent strata pressure behavior and catastrophic accidents easily occurred...