Source Analysis And Comprehensive Control Technology Of Gas Gushing In Multi-coal Seam Occurrence Working Face Mining In Qianjin Coal Mine

In the process of multi coal seam mining,the occurrence gas has the characteristics of multiple pressure relief effect,Complexity is a basic feature of gas emission,there are many difficults with the gas control in the working face.In paper,according to the condition of multiple coal seams in Qianjin,we studied the law of gas emission in multiple coal seams by experiments,theoretical analysis and field measurement.Combined with the situation of Qianjin mine,we established the gas control technology measures that apply to 2906 working face and 21506 working face,and the dynamic adjustment and effect inspection are carried out simultaneously.In this paper,according to field measurement,laboratory measurement and theoretical analysis,the content gradient law and pressure gradient law of gas occurrence in multiple coal seams in Qianjin coal mine are studied;the gas emission law of coal wall in 2906 haulage roadway and 21506 haulage roadway are measured;the gas emission law of coal mining in 2906 haulage roadway(9 coal)and 21506haulage roadway(15 coal)is tested;the gas emission law of coal mining in Qianjin coal mine is investigated.The relationship between the residual gas content and the exposure time of No.9 and No.15 coal seams in the coal mine;the gas emission source and composition of Qianjin coal mine comprehensive working face are analyzed.In the mining process of 2906 working face,the gas emission of this coal seam accounts for 66%?69%,with an average of 68%,the gas emission of adjacent coal seam accounts for 30%?34%,with an average of 32%.The gas emission is mainly from this coal seam;21506 working face in mining on Qianjin coal mine.The gas emission of this coal seam accounts for 47%?51%,with an average of 48%.The gas emission of the adjacent layer accounts for 49%?53%,with an average of 52%.The gas emission is mainly from the adjacent layer.Based on the research results,the gas control measures of"drilling along the seam+burying pipe+intubation"are put forward for the 2906 working face.In the later mining process,the total amount of drilling along the seam in the 2906 working face area is about 1171000 m³.The measured residual gas content is 2.2388?5.8985m³/t,and the gas concentration in the return air flow is less than 0.8%,which has achieved good gas control effect.According to the 21506 mining face,"high drilling+buried pipe+intubation"gas control measures are proposed,and the high drilling parameters are dynamically adjusted in the mining process.In the later mining process,the single hole concentration of high drilling reaches 60?70%,intubation concentration 20?28%,and buried pipe 8.8?12%.The highest gas concentration in the upper corner is 0.47%,with an average of 0.2%;the highest gas concentration in the return air flow is 0.31%,with an average of 0.22%.The S value of the working face is 1.8?2.0kg/m,and the value of?H₂ is 100Pa.