Study On Prevention And Control Of Coal Mining Water Damage In Group A Of Steeply Inclined Coal Seam At Huainan Mining Area

In the period of the whole coal mining,the mine water damage has been one of the main threats.The steeply inclined coal seam is one of the important coal resources in China.It is widely distributed and has abundant reserves.In the mining of steeply inclined coal seam,the threat degree of mine water inrush is greater,and the mining of coal seam is seriously threatened.Therefore,the prevention and control of water damage in the mining of steeply inclined coal seam is of great significance.The geological structure and hydrogeological conditions of the steeply inclined coal seam in Huainan coalfield are complex,and the coal seam mining is very difficult.With the depletion of the shallow resources,the mining area is gradually turning to the coal mining in the group A.Because the coal mining in the A group is threatened by the Taiyuan limestone aquifer of the floor,the difficulty of coal mining is further increased.Therefore,it is necessary to study the prevention and control of water damage in the mining of the steeply inclined coal seam in group A in the Huainan mining area.Steeply inclined coal seam in Huainan coalfield are mainly distributed in the Huainan mining area in Lizuizi Mine and Xinji NO.3 Mine in Xinji Mining Area(It used to be the Balitang Coal Mine).Based on collecting Lizuizi Mine and Xinji NO.3Mine exploration stage and the stage of production data,the mine mining engineering geological and hydrogeological conditions are analyzed.It puts forward targeted methods of prevention and control,and the results are as follows.(1)It is proved that there is a certain relation between the Taiyuan limestone aquifer and the Ordovician limestone aquifer under floor of group A by using the water quality type evaluation and the grey correlation method.(2)According to the drilling data statistics,the floor aquifuge thickness of group A in Lizuizi Mine is small.The distance between the 3 coal seams in the Xinji NO.3Mine is close to that of the overlying limestone aquifer.Both have the possibility of water inrush.(3)FLAC3D numerical simulation software is used to study the evolution law of coal floor failure in A group of Lizuizi Mine.The results show that the failure depth of the coal mining floor in the A group is 22 m.The failure range of floor mining may affect the underlying limestone aquifer.(4)Using UDEC numerical simulation software to study the roof failure of No.3coal mining in Xinji No.3 Mine.The results show that the development height of the water flowing fractured zone of the roof is between 31.03m~33.0m.The development of water flowing fractured zone of the roof may extend to overlying limestone aquifers.(5)According to group A coal hydrological engineering geological conditions in Lizuizi Mine and Xinji No.3 Mine combined with mining practices,it is proposed that the methods of prevention and control of the floor coal water damage in the steeply inclined A group coal seam are as follows: drainage and decreasing pressure,pressure limiting mining,sand control and closure by grouting.The method of prevention and control of roof water damage is the combination of drainage and decreasing pressure and grouting reinforcement.It summarize the method of prevention and control of water damage of the steeply inclined coal seam in group A in the Huainan mining area.The research results can provide a good reference and guidance for the mining of steeply inclined coal seam with similar conditions.