Study On The Accumulation Characteristics Of Gas In The Goaf In The Goaf Under The Conditions Of Extraction

The gas concentration in the upper corner of the goaf is an important indicator for the normal and safe production of the production face.For China,most of the mine production working face adopts U-shaped ventilation system.The drawbacks of the ventilation system lead to the accumulation of gas in the upper corner of the road,which has always been an important indicator that plagues the production safety working surface.In addition to the ventilation system,the problem of gas accumulation in the upper corner is directly related to the leakage of the goaf to the working face.Due to the problem of air leakage in the goaf and over-limitation of gas in the upper corner,most of the production work faces in China have adopted the extraction measures in the goaf.Therefore,it is very necessary to study the influence and mechanism of the air leakage from the goaf in the extraction conditions on the accumulation characteristics of the upper corner gas.In this paper,the 12409 working face of the Red Mine in Shaanxi Province is taken as the research object.Through the theoretical analysis of the research topic,the basic laws of gas migration in the goaf and air leakage in the goaf are obtained,and the goaf of the 12409 working face of the coal mine is passed.The air leakage area is divided,and the main components of the air leakage in the coal mine goaf are obtained through the actual measurement of the air volume distribution along the working face,and the flow pattern of the air leakage in the goaf of the 12409 working face of the coal mine without the extraction measures.Through the high-level drainage conditions of the 12409 working face of the mine,the distribution of air volume along the working face under different pumping flow rates,the air leakage strength,the extraction data,and the pressure difference of the return air side of the working face are measured and analyzed comprehensively.In actual production,increasing the pumping flow rate will reduce the air leakage on the return air side of the working face,and reduce the air leakage flow range on the return air side of the goaf,thus obtaining the air leakage to the upper part of the goaf under different pumping flow rates.The initial influencing mechanism of the angular gas accumulation characteristics.Finally,combined with theoretical analysis and actual monitoring data,the geometric model is established according to the actual situation of 12409 working face,and the distribution of gas concentration in goaf under different working surface air distribution is analyzed by numerical simulation of fluent software.The relationship between the air leakage side of the return air side of the goaf,the influence range of the gas concentration of the extraction,and the change of the gas concentration of the upper corner are obtained,and the gas accumulation in the goaf of the goaf is obtained under the extraction conditions.The influence mechanism of the coal mine is 150m3/min-210m3/min.