Study On Coal Seam Gas Occurrence Characteristics And Control Measures Under Igneous Rock Bed Erosion

With the continuous development of coal mining,the problem of gas protrusion in mines is becoming more and more serious.When magmatic rocks intrude into the coal seam,the gas in the coal seam does not easily escape due to the nature of the magmatic rocks themselves,thus increasing the gas pressure in the coal seam.And when discontinuous magmatic rocks intrude into the mining area,because they are scattered in the mining area,it leads to more complex geological conditions in the mining area and makes mining much more difficult.Therefore,in order to effectively control the risk of protrusion under discontinuous magmatic rock erosion,the coal and gas protrusion risk under discontinuous magmatic rock erosion environment is predicted and evaluated with 7401 working face in the four mining area of Zouzhuang coal mine as the engineering background,which has a very important role in the safe production of the mine.The following conclusions were drawn.(1)Based on the basic theories of magmatic rock and coal and gas protrusion,it is found that the influence of discontinuous magmatic rock erosion on coal seam gas shows regional characteristics.The mechanical analysis of coal seam mining in the completely eroded area,partially eroded area,missing area of magmatic rocks and unaffected area under discontinuous magmatic rock erosion is studied.(2)By analyzing the risk of coal and gas protrusion under discontinuous magmatic rock erosion,the factors influencing the risk of coal and gas protrusion under discontinuous magmatic rock erosion are determined to be magmatic rock factor,coal and gas factor and geological structure factor.And these factors were analyzed and evaluated by using hierarchical analysis method,and it was concluded that geological structure factor has the most influence on gas protrusion control measures.(3)The local prediction sensitivity indexes of the mine,such as drilling chip desorption index and drilling chip amount Smax,were characterized,and the gray prediction model of nonlinear science was applied to actively explore and practice the local prominence prediction indexes,and the prediction results that match with the actual measurement were obtained,and the accuracy reached the prediction requirements.(4)Based on the analysis and research on the geology and mining technology conditions of 7401 working face,four gas protrusion control solutions were proposed in combination with the overall technical scheme of "protective layer mining + extraction".The optimal choice of gas protrusion prevention and control scheme was obtained by grey weighted clustering method and successfully applied to the actual project.