High Efficient Gas Drainage Technology And Its Application In No.6 Coal Mine Of Hebi Coal Power Co.,Ltd

The NO.6 coal mine of Hebi Coal Power Co.,Ltd belongs to a single thick coal seam high gas prominent mine,with the increase of coal seam gas content and gas pressure gradually increased,resulting in the increase of coal seam prominent danger.This geological factor manifests it in the process of coal lane excavation area verification many times exceeding the standard,digging speed seriously restricts the mine production replacement work;From this,it can be seen that the mine uses comprehensive coal seam gas is the safest and most reliable method of preventing and using coal and gas prominent technology.The main methods of extraction are comprehensive extraction gas technology combining layer drilling,sub-layer drilling,top plate high drilling and extraction in the mining area.In order to improve the effect of gas drainage in coal seam,Hebi No.6 Coal Mine studied the technology of optimizing the hole layout to improve the effect of gas drainage,and optimized the existing problems in the current drainage holes,so as to achieve the purpose of gas drainage and eliminating the risk of coal seam outburst.Based on the basic parameters of gas extraction in the existing the sixth coal mine coal seam,the basic situation of gas extraction and the existence of major problems,gas geology,this paper puts forward the gas extraction technology suitable for the high-burst coal seam of NO.6 coal mine of Hebi Coal Power Co.,Ltd according to the conditions of coal seam gas extraction and diffusion-seepage theory.The following conclusions are drawn:(1)The characteristics of gas storage and gas gushing out of the 2145 bottom pumping lane of The Sixth coal mine of Hebi Coal Power Co.,Ltd were analyzed,and the gas content of the work surface was 4.11-10.12m³/t,of which the highest value was reached at 500 m,while the combustible base reached a maximum of 10.12m³ at 650.The gas pressure measured was 1.65MPa relative pressure and 1.76MPa,while the coal seam gas gushing showed a negative power index decrease trend over time,with the correlation coefficient squared to 0.9351 and the drilling attenuation coefficient0.0192d^-1.(2)Combined with the actual situation of the sixth coal mine,it is found that the drilling depth and the sealing quality of the borehole are the key to affect the concentration of gas extraction.The drilling technology,including drilling process,sealing length and sealing depth,clearing process,material and seal pipe length,special section of the sealing technology,etc.,is adopted to optimize the drilling extraction gas sealing technology model to improve the extraction effect.(3)In the aspect of extraction negative pressure optimization,the appropriate hole negative pressure needs to consider all aspects of factors.It can be calculated that under the condition that the sealing hole quality is satisfied,the new hole negative pressure can ensure that the gas concentration in the hole tube is not less than 45%.(4)Through the analysis of the effect of extraction optimization,it is found that:100 meters drilling pumping volume in general with the extraction time extension showed a decreasing trend.Perforated drilling sealing effect is generally better than coal hole sealing effect,extraction of coal seam gas with the extraction time extension of the effective extraction radius increased,but increased to a certain range tends to balance,extraction effect will be reduced,need to take certain measures to enhance the permeability of the coal seam to improve the extraction effect.(5)Before comparison and optimization,the purity of coal seam gas extraction increased gradually with the increase of extraction time.The drilling purity of the perforated drilling reaches more than 3 times the purity of the coal seam extraction,the rate of increasing the purity of the perforated drilling is greater than the rate of the increase of the drilling extraction of the coal seam,and the concentration of gas from the ground extraction pump is increased from 14%to 17%.This paper has 32 figures,15 tables and 81 references...