Study On Ascending Mining In The Mine Of Hejiata

In the group layers of coal seams and the layering thick coal seam, we generally use thedescending coal mining in every coal seam, however, in some special cases adopt ascendmining may receive better results. Hejita coal mine has a three-tier of minable coal seam, thelayer are 3-1,4-2,5-2 from top to bottom, among them, the coal-tier of 3-1, 4-2 are thin coal seamand the 5-2 coal is thick coal seam. If adopt the traditional production method of descendingcoal mining, coal is by 3-1→4-2→5-2 coal mining coal sequence, the initial exploitation of thethin coal seams, low output, low efficiency and poor benefit. Conversely, if adopt the ascendmining. first coal mining 5-2, then mining 3-1 coal ,4-2 coal , initial yield large output, highefficiency and rich benefit, conducive to the development of mine. In this paper, study ascendmining feasibility of Hejita coal mine.Through the simulation experiment research,after 5-2 coal mined appear three zones,thatheight of the caving zone is 18m,Highly fractured zone is 54m, 4-2 coal is in the curvesubsidence zone after 5-2 coal mined,show that 5-2 coal mining have little influence 4-2 coal.Through numerical simulation research, 5-2 after the coal mining in 4-2 coal floor place stressand displacement, the maximum stress little change for 0.25MPa less than floor rock tensilestrength 2Mpa; along the vertical direction mining maximum lowering value 0.09m; theplastic zone is not evolution to 4-2 coal. 5-2 coal mining does not affect the upper 4-2, 3-1 thenormal mining ,conclude that ascending mining feasible. the conclusion of that height of thecaving zone is 11.26m,highly fractured zone is 55m,and ascending mining necessarySurrounding balance height is 42.5m, while the minimum space is 93.7 m between 4-2coal and5-2 coal above surrounding balance,conclude that ascend mining is feasible. The aboveanalysis conclude that the coal-tier 5-2 have little effect to it's upper coal-tier 3-1 and 4-2 coal,and conclude that the ascend mining is feasible in the Hejita coal mine.The research provided areference for ascend mining and opened up a new way for resolving the similar issues.The attempts of the ascend mining, it's not only enriches the theory and practice of ascend mining, while have important practical value and practical significance for improving theresource recovery rate in Hejiata coal mines.