Research On The Technology Of Gas Outburst In The Bottom Roadway Of The South Third Mining Area Of ??Shaqu No.2 Mine

At present,the main gas pre drainage by drilling gas drainage method,the main wear layer and hole drilling in two ways,which are suitable for different conditions of coal seam.According to the characteristics of the three mining area in Shaqu mine south two coal seam(high gas and low permeability,coal and gas outburst),and 3#,4# in the three South Eastern coal mining area coal seam spacing,design 3+4# section with mining,basically do not have the protective layer mining conditions,therefore according to the "coal and gas outburst prevention regulations" relevant regulations,outburst prevention plan using pre pumping coal seam gas in the southern region of the three mining area.The southern three mining area 3+4# coal seam and 5# coal seam roadway construction without adjacent bedding long borehole conditions,and considering the mining face under the layer of pressure relief drainage needs,so the southern three mining area using coal seam floor borehole gas drainage of the regional outburst prevention measures.This paper introduces the measures for outburst bottom pumping alley wear pre drilled layer seam gas drainage area in engineering practice in three District of Shaqu mine two south,and the main measures of the outburst prevention effect and application effect were investigated.Comprehensive drilling surrounding rock stress distribution,gas drainage flow of two kinds of theoretical calculation method and COMSOL numerical simulation,combined with the drainage time,determine the three mining area coal seam gas Shaqu mine south two effective drainage radius is 2.5m;with the drainage time,gas should be comprehensive drilling surrounding rock stress distribution,gas drainage flow of two kinds of theories calculation of the effective drainage radius,borehole drainage numerical simulation calculation and COMSOL gas hole spacing,determine the reasonable distance of gas drainage borehole drilling for 5.0m,at the midpoint of coal seam gas pressure is reduced to 0.58 MPa,less than 0.74 MPa.Combined method to calculate the residual gas pressure through the field test of residual gas content and theory to test the effect of the regional outburst prevention measures,the results indicated that the original gas content decreased by 56.7%,the original gas pressure decreased by 61%,and were less than the critical value of "Regulations of coal and gas outburst prevention regulations" in the.The K1 value of the gas desorption index of drill cuttings and the S value of drilling cuttings are all less than the critical value given by the regulation of preventing coal and gas outburst.