Study On The Gas Solid Extraction Technology Of Soft Coal Seam In Xiangshan Mine

Gas drainage is one of the most fundamental ways to prevent and control gas disasters.High efficiency and healthy operation of gas extraction system is the premise to ensure the effect of pumping.At present,most of the gas drainage system in our country has been established for some time,and gradually exposed more and more problems.The paper establishs a evaluation index system and comprehensive evaluation model of gas drainage system based on the pumping test and analysis of running parameters of XiangShan coal mine and the present situation of lack of the systematic evaluation theory system of gas drainage system in coal mine.The XiangShan coal mine gas drainage system is evaluated by the comprehen-sive evaluation system.The paper combines with XiangShan coal mine gas drainage system operation rules and evaluation results of the XiangShan coal mine creatively to optimize the gas drainage system.It has important practical significance to solve problem in the XiangShan coal mine gas drainage system and ensure the safety of production.Through the study of gas occurrence and migration in 3,5 and 11 coal seam of the object mountain mine,it is concluded that the occurrence rule of gas in Xiangshan mine is the result of multiple factors such as buried depth,floor elevation,geological structure and so on,and the influence factors of each coal seam gas occurrence are also different.Because the geological structure of Xiangshan mining area is mostly distributed in the edge of the mine,the gas content at the edge of the minefield is small and the gas content in the middle of the mine is large.For the 3 coal seams,the gas content from north to south is gradually high-low-high in the range of the well field.The Xiangshan mine is a soft coal seam.By studying the SEM diagram of soft hard coal,it is found that the pores and pores of the soft coal are complex,which provides larger space for gas storage and makes the migration of gas in it relatively complex.According to the current status of mining and gas occurrence and migration in Xiangshan,a gas solid drainage system is designed,which is composed of surface gas drainage boreholes,gas drainage boreholes and coal seam gas drainage boreholes.According to the characteristics of coal seam in this working face,a boring and hole forming technology suitable for soft coal seam is put forward,that is,whole casing method.This method can effectively block the area of coal seam damaged in the open hole area,so as to improve the gas drainage rate of boreholes.According to the process of sealing pressure sealing technology principle and the"two block a" belt,design a new type of pressure sealing device.The implementation process is as follows:by withholding water but the mechanical pulp banding pressed on drainage pipeline,through the injection of quick setting cement slurry and the drilling expansion sealing section to form an effective confined space,and then to the closed space with pressure injection of cement paste for sealing.Based on the analysis of the mine gas drainage system,a hierarchical model of the reliability evaluation of the gas drainage system is established,and the gas drainage system of the soft coal seam in Xiangshan mine is evaluated.The safety level obtained is in line with the actual situation.Therefore,this comprehensive evaluation method is feasible for the evaluation of the three-dimensional gas extraction system of the soft coal seam,and also provides the basis for the evaluation of the similar mine extraction.