Impact Assessment Of104Mining Area’s Limestone Water To Exploitation Of10Coal Seams In The Qingdong Mine

With well-developed situation of the limestone aquifer in the coal floor of coal seam, NO.10mining area in Qingdong coal mine of Huaibei mining group, as well as the maldistribution of the thickness in the floor of aquifer, the water inrush was easy to be emerged under the synergism of both limestone water pressure and mining failure. Therefore, the floor of coal seam and the characteristic of limestone were undertaken to be researched in this paper.Both the geology condition of limestone floor and hydrogeololgical characteristic in104mining area were analysed firstly, and the appearance of a closed unit, as well as weak run-off and strong or moderate water-richness were indicated, in limestone aquifer (from1~th to4~th) of Taiyuan group. And the conclusions about hydrogeological conditions of karst collapse column could hardly be formed was achieved, through a series of researches on the forming conditions about mining geology, hydrogeology and karst collapse column. Secondly, the failure depth of floor under the influence of mining was predicted by utilizing gray BP neural network and finite element simulation, and then achieved the closely similar results that, the average was14.65meters. The integrity analyses of10th water-barrier floor in NO.104mining area, were undertaken through fractal theory, and then the conclusions of the favorable watertight performance were achieved by combining aquifuge thickness and lithological conditions. The weak water-richness in faultage, yet the butt joint between10~th coal seam and limestone were indicated to cause the possibility of water-inrush, through numerically simulating influent flow conditions in10~th coal seam. And theoretical analysis results of water inrush coefficient indicated: the high water pressure of limestone aquifer, and thin aquifuge of the floor, which was in the state of "overrun exploitation" to cause the possibility of limestone water inrush. Finally, to use the formulas of "Steady flow" and "non-steady flow" to predict the water inflow of the mining area, the results showed that the maximum water inflow was498.35m3/h, which was within the drainage capacity of the mine. To use fuzzy comprehensive evaluation theory evaluate the risk of water inrush, in the floor of NO.10coal seam, and the demarcations were divided, according to the the risks of water-inrush, then provided the references for the preventions and control measures in mining NO.10coal seam.Figure47table32reference62...