Evaluation On Water Abundance Characteristics And Water Inrush Risks Of The Limestone Aquifer In Taoyuan Coal Mine

The water inrush accident is easy to happen when the Taoyuan Coal Mine is threatened by the Limestone Karst Aquifer when mining the deep 10 coal seam of Permian System.According to the statistics,there were 17 times of water inrush from 10 coal floor and 5 times of Water Inrush over 100 m3/h in Taoyuan Coal Mine,which had a great influence on safety production.In order to ensure the safe opening of deep coal seam in Taoyuan Coal Mine,it is necessary to study the water-rich characteristics of Limestone Aquifer and the risk of water inrush from coal floor.(1)the hydrogeological conditions and water-rich characteristics of 1-4 limestone in the upper section of Taoyuan coal mine are analyzed based on the thickness of Limestone Aquifer,karst development,hydrodynamic characteristics,hydrochemical characteristics and pumping test results.It is concluded that 1-4 limestone karst in the upper member of Taiyuan formation is not well developed,and most of them are fractures.The 1-4 ash aquifer is weak to strong water-rich and unevenly distributed.(2)according to the characteristics of lithologic combination of floor and fractal dimension of fracture structure,the water-resisting ability of 10 coal floor is analyzed,and it is concluded that the water-resisting floor of Taoyuan Coal Mine is sand-mud interbedded and the water-resisting condition is better,the areas with strong structural development are mainly distributed in the south third mining area of the mine and near the F2 fault in the north.By means of numerical simulation software FLAC3D,the damage depth of 10 coal floor is simulated,and the maximum damage depth is 13.73 m according to geophysical data,the average thickness of the effective water resisting layer in the 10 coal floor of Taoyuan Coal Mine is 47.77 m.(3)according to the method of Water Inrush Coefficient,the value of water inrush Coefficient in the boreholes of Taoyuan Coal Mine is calculated.From the contour map of water inrush coefficient,the value of water inrush Coefficient from west to east of Taoyuan Coal Mine is getting bigger and bigger,and the value of water inrush Coefficient in most areas is greater than 0.06.By means of Fuzzy and comprehensive evaluation,taking the thickness of limestone 1-4 Aquifer,water inflow per unit,water pressure of Limestone Aquifer,thickness of effective water resisting layer,sand content of water resisting layer and fractal dimension of fracture as evaluation indexes,the risk of water inrush from 10 coal floor is comprehensively evaluated and subdivided,the risk of water inrush in Taoyuan Coal Mine is divided into relative safe area,relatively dangerous area,dangerous area and extremely dangerous area.The results show that the extremely dangerous area is mainly distributed in the north of the coal mine and near the third mining area in the south,from West to east,the risk level in central region gradually changed from relative safe area to dangerous area and then to extremely dangerous area.Based on the analysis of the water-rich characteristics of limestone in Taoyuan Coal Mine and the evaluation of the risk of water inrush,this paper provides the basis for the corresponding prevention and control measures in the process of 10 coal mining.Figure[26]table[25]reference[76]...