Gas Enrichment Regularity And Geological Controlling Factors Of 8₁^# Coal In Yangquan Wen Jiazhuang Mine

Through studies such as observation, sampling, combined with various experiments, coal characteristics and gas occurrence regularity and control factors of 8₁^# coal in Yangquan Wen Jiazhuang Mine are studied.Coal characteristics of 8₁^# coal are studied by SEM, mercury injection and gas adsorption isotherm test et al. The experiments analysis results of SEM, mercury injection show that, pore of the 8₁^# coal are development and they are mainly transition pore, accounted for about 50%. The experiments analysis results of gas adsorption isotherm test show that, adsorptive gas content of 8₁^# coal is between 32-37cm3/g, its adsorptive capacity of gas is strong.The performance of the gas occurrence regularity of Yangquan Wen Jiazhuang Mine is that gas content and gas pressure distribute with the trend of "south high north low, east high and west low", they are both affected by the depth of coal seam.Research shows that, geological controlling factors of 8₁^# coal seam gas enrichment mainly include geological structure, depositional environment, coal seam depth, the metamorphic degree of coal, hydrogeological conditions et al. And the buried depth of coal seam is the main control Wen Jiazhuang mine 8₁^# coal seam gas enrichment factors. In the aspect of structure, Wen Jiazhuang mine small faults and collapse column is developed, gas content in the structure is mainly by small fault and subsided column. In the aspect of sedimentary environment, the development of 8₁^# coal seam containing lingulata marine mudstone. Therefore, Wen Jiazhuang mine 8₁^# coal seam formed in delta front distributary Bay filling evolution of peat bogs in formation. The influence of gas enrichment is mainly manifested in the development of the coal seam thickness and coal seam roof and floor lithology development. From the relationship between the gas content and coal seam thickness in 8₁^# coal seam, the correlation coefficient of gas content and the thickness of coal seam is only 0.0432, with a low correlation. The main controlling factors of gas content is not the thickness of coal seam in Wen Jiazhuang mine, but the thickness of coal seam is still some effects to a certain extent. Wen Jiazhuang mine 8₁^# coal seam roof and floor mainly mudstone, sandy mudstone, and only in a borehole exposing its immediate roof is fine sandstone. The thickness of mudstone is much larger than the thickness of sandstone, is conducive to the enrichment of gas. In the aspect of coal seam depth, the level of the trend of the coal seam depth and gas content is basically consistent, from north to south, increased gradually from the west to the east. Coal seam gas content and is closely related to the depth, and the coal seam depth is the main control factors of gas enrichment Wen Jiazhuang mine. In the aspect of metamorphosing degree, Wen Jiazhuang mine 8₁^# coal mainly belongs to the lean coal and anthracite, a large amount of gas generation, and the adsorption quantity of gas is large, it is beneficial to gas enrichment. In the aspect of pore characteristics of coal, 8₁^# coal seam pores and fractures are well developed, the small hole and the micropores developed very well, they increase the surface area of coal, enhance the capacity of coal adsorbed gas, it is beneficial to gas enrichment.According to the distribution of gas unusual emission points in the Wen Jiazhuang mining area, the gas outburst occurs easily in those conditions that geological structures are complex, coal seam depth is deep, gas pressure and gas content are high, the prevention measures of coal and gas outburst are summarized.