Study On Gas Drainage Technology Of No.9 Coal Seam In Wuhushan Mine

Coal is one of the important pillar industries of energy in our country.With the continuous expansion of coal mining scale,coal mine gas has become an uncertain factor threatening people’s production safety.Therefore,it is necessary to carry out gas drainage for high gas mines.In order to achieve the effect of gas drainage and meet the requirements of the standard,it is necessary to determine the gas drainage radius of coal seam.In this paper,the 9# coal seam of Wuhushan mine is taken as the research object.By measuring the gas parameters of 9# coal seam,the gas occurrence law of 9# coal seam is analyzed.Then,by using the method of numerical simulation and field measurement,the process of gas drainage in 9# coal seam is studied,and the results under different drainage conditions are compared,the effective radius of gas drainage is obtained,and the parameters of gas drainage are optimized.First,the basic parameters of 9# coal seam gas are measured on site,and the gas pressure prediction model and gas content prediction model of 9# coal seam are obtained.On the basis of the obtained parameters,the mathematical model of coal rock gas solid gas coupling is established,and the numerical simulation of 9# coal seam gas pre extraction is carried out in Wuhushan coal mine.The results show that:(1)the reasonable suction negative pressure of the long borehole along the strike of Wuhushan coal mine is 30 k Pa,the pre extraction time of 9# coal seam working face is1 year,the long borehole spacing along the strike is 10 m,and the working face of 9#coal seam is pre extraction The pumping time is 1.5 years,the long borehole spacing along the strike is 15 m,the pre pumping time for the 9# coal seam working face is 2years,and the long borehole spacing along the strike is 20 m.(2)In Wuhushan coal mine,the reasonable extraction negative pressure of inclined borehole is 20 k Pa,the pre extraction time of 9# coal seam coal face is 2 months,the spacing of inclined borehole is 2m,the pre extraction time of 9# coal seam coal face is 4 months,the spacing of inclined borehole is 4m,the pre extraction time of 9# coal seam coal face is 6 months,and the spacing of inclined borehole is 6m.According to the numerical simulation results,the field test is carried out.The comprehensive methods of pressure drop method,reserve method test and content method verification are used to determine the effective extraction radius of 9# coal seam.Through the test of 010909 working face and the observation ofdepressurization method,it is found that the effective extraction radius of 94 mm bedding hole is greater than 3m and less than 6m for continuous extraction of 9# coal seam for 180 days;the effective extraction radius of Wuhushan 9# coal seam inclined to bedding hole for 180 days is 3.1m by reserves method test;after continuous extraction of observation hole(180 days),the effective extraction radius determined by observation hole is 3.1m The residual gas content of coal seam was measured near the edge of coal seam,and the test results were verified to be reliable and effective,meeting the requirements.The paper has 38 figures,30 tables and 70 References.