底抽巷一巷两用瓦斯治理技术实践

Practice on Gas Control Technology of Floor Drainage Gateway with Two Uses

为解决保护层开采瓦斯抽采中底抽巷利用率不高,工作面瓦斯浓度控制效果差,巷道及钻场布置成本较高的弊端,结合顾桥煤矿的地质条件,合理确定底抽巷的位置及瓦斯抽采钻孔的布置,采用底抽巷"一巷两用"瓦斯抽采方法,既抽采上覆被保护层的卸压瓦斯,又抽采下伏保护层回采后采空区及上隅角的瓦斯。采用底抽巷抽采后:被保护层瓦斯最大和最小残余瓦斯压力分别为0.49、0.21 MPa,平均0.38 MPa,较煤层原始瓦斯压力0.67 MPa明显降低。随着抽采进行,回风流瓦斯体积分数控制在0.17%左右,上隅角瓦斯体积分数在0.7%以下,瓦斯抽采体积分数在30%左右,抽采量在50 m3/min以上。

In order to solve the low utilization ratio of the floor drainage gateway in the gas drainage of the protective coal seam mining, the low control effect of the gas concentration in the coal mining face and the high layout cost of the gateway and drilling site, in combination with the geological condition of Guqiao Mine, the location of the floor drainage gateway and the layout of the gas drainage boreholes were rationally determined.The gas drainage method in the floor drainage gateway with two uses was applied to drainage the pressure released gas from the above protected seam and to drainage the gas in goal and upper comer after the mining operation in the underlying protective coal seam. After the gas drainage operation completed in the floor drainage gateway, the maximum and minimum residual gas pressure in the protected coal seam after the pre-drainage was 0.49 and 0.21 MPa individually.The average pressure was 0.38 MPa and was much lower than the in-situ seam gas pressure of 0.67 MPa.With the gas drainage operation conducted, the gas volume fraction in the air returning was controlled at about 0.17% ,the gas volume fraction in the upper corner was below 0.7% ,the gas drainage volume fraction was about 30% and the gas drainage quantity was above 50 m3/min.