Comprehensive gas extraction technology for new and old goafs in gob-side entry retaining working face
Gob-side entry retaining application is becoming more and more common.However,the application of the gangue bracket is convenient for hanging and injection molds,it forms a drawer-type semi-enclosed space,which is easy to accumulate gas.In addition,due to the lack of coal pillar isolation,a large goaf will gradually form from the first mining face to the last mining face.The gas in the old goaf is affected by secondary or even multiple mining operations,and the accumulated gas in the new goaf is rapidly gushing out,leading to frequent risks of gas exceeding limits and even leading to gas accidents.For this reason,the gas control technology for long boreholes was further optimized:on the one hand,gas extraction from fractured zones was carried out through high-level boreholes with a strike direction;on the other hand,the construction tended to drill at a high level to the fractured zones on the roof of the old goaf,con-tinuously extracting gas from the new and old goaf,and minimizing the gas storage in the goaf and its roof fractured zones.The compre-hensive gas extraction in the new and old goaf has achieved significant results in gas control in the working face.
gob-side entry retaininghigh-level boreholeupper cornergoaf gas
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