Study On Occurrence Characteristics Of Gas And Drainage Method In Jiaoping Mining Area

Jiaoping mining area is a rare mining region of China in which coal, oil and gas associate. The large amount of gas from coal-bed and layer becomes the main factor that affects mine safety. By studying coal gas's formation, storage and emission characteristics and discussing the volume forecast of gas flow-volume, it is one of the main methods to prevent gas accidents.Through collection coal samples of Jiaoping mining area's two main production mine to be on proximate analysis, coal and rock composition analysis, coal-based surface characteristics analysis(SEM analysis), pores distribution and pore volumes characteristics analysis(porosity analysis, mercury penetration experiment, liquid nitrogen adsorption experiment), adsorption and desorption characteristics analysis(isothermal adsorption and desorption experiment) and mass of experimental data was analyzed, organized and mathematical fitted, the analysis shows that Chenjiashan 4#coal's liquid nitrogen adsorption capacity and mercury penetration saturation degree are larger than Xiashijie 4#coal. On 4#coal of two mines, the pore shape show as parallel plate crevice and open form. And the pore throat of Chenjiashan 4#coal show as bottleneck. The openness on Chenjiashan 4#coal's pore is better than Xiashijie 4#coal. Based on coal-based surface characteristics and the discrepancy of energy distribution, we select Weibull function, which influence by desorption discrepancy on sorbent surface, to describe desorption. Combined the isothermal adsorption experiments of Langmuir function model with experimental data desorption Weibull function, it shows that adsorption heat of Chenjiashan 4#coal is less than Xiashijie 4#coal and desorption of Chenjiashan 4#coal is easier than Xiashijie 4#coal.After evaluated the gas drainage probability, Jiaoping mining area coal bed gas have drainage probability. According to the characteristics of the intergrowth of coal, oil and gas, short cycle of coal seam natural catching fire, large gas emission amount, coal seam texture unsteadiness and discrepancy of coal mechanics parameters, it is suggested that roof gas drainage is the main means for mining safety. While excavating coal, gas drainage in current seam is the supplementary mean to ensure mining working safely, continuously, stably and effectively.