Influence and Treatment of Gas in Goaf on Upper Corner of Small Coal Pillar Mining Face
In order to eliminate the influence of gas accumulation in the adjacent goaf on the upper corner of the small coal pillar mining face,taking the 2305 mining face of Xiahuo Coal Mine of Shanxi Sanyuan Coal Industry Co.,Ltd.as the prototype,based on the research on the gas migration law in the goaf,three methods of drilling,parallel connection of goaf extraction branch pipes,and laying of dedicated pipelines were designed and selected for comparative extraction experiments,the effectiveness of different extraction forms and flow rates on gas control in goaf was analyzed.The results show that after the mining face enters the 8 m small coal pillar area,the gas in the goaf flows towards the current mining face through the roof cracks,and the volume fraction of gas in the upper corner increases significantly.Before extraction,the gas migration law in the goaf is that the gas near the mining face migrates to the vicinity of the current goaf extraction port.After extraction,the gas migration law in the goaf is that a small part of the gas near the mining face still migrates to the vicinity of the current goaf extraction port,and the majority migrates from the inside to the outside of the current goaf extraction port.The use of dedicated pipelines for extracting accumulated gas in the goaf has a good effect,which can significantly change the direction of gas migration in the goaf.The volume fraction of gas extracted by buried pipelines decreases with the decrease of gas volume fraction in the goaf.The two have a strong correlation,and this extraction method can effectively eliminate the influence of accumulated gas in the upper corner of the small coal pillar mining area.
small coal pillar mininggas control in upper cornergas extraction in goaf
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