Study On Gas Drainage Technology In Yuhua Coal Mine

In terms of energy supply in China,coal has always occupied a major position.However,along with the exploitation of coal resources,accidents continue to occur,especially those caused by gas emerge in an endless stream,and they are quite serious.Gas extraction is the only way to solve gas accidents,so in order to improve the effect of gas extraction,it is necessary to select appropriate gas extraction technology.For short-distance coal seam mining,protective seam mining is the most effective and economical technical measure to prevent gas disasters.This paper takes the 1# and 2# coal seams of Shanxi Yuhua Coal Mine as the research object,and studies the gas occurrence law of Yuhua Coal Mine by measuring the gas parameters of two coal seams.Taking the 2301 working face as an example,the advantages and disadvantages of the original pumping system of Yuhua Coal Mine were analyzed and the new extraction scheme of protective layer gas extraction was proposed.The scheme adopts the 1# coal seam of 10-12 m from the 2# coal seam as the protective layer.During the mining of the 1# coal seam,the 2# coal seam pressure relief gas is extracted by the high-level drilling and the goaf of the goaf;when the 1# coal seam is recovered After the end,the pressure relief gas during the recovery of the 2# coal seam is extracted through the buried pipe in the goaf to ensure the safe recovery of the 2# coal seam.In addition,numerical simulation(FLAC3D)was used to study the pressure relief law of the protective layer mining floor,and analyze the influence of the upper protective layer on the pressure relief law of the lower protective layer during the mining process.It is found that the pressure relief front of the bottom plate will move forward with the working face,and the full pressure relief area will dynamically move forward with the mining of the working face.The deep pressure relief area is maintained in the range of 20m~50m from the working surface.According to the results of numerical simulation,the pressure relief range of the upper protective layer was investigated by field test.The results showed that the upper protective layer had a relief angle of 53° and a tendency to relieve pressure of 72°.On the basis of the above research,the 2# coal seam 2305 working face was subjected to the protective layer gas drainage field practice.The research shows that the gas concentration in the working face can be effectively controlled within 0.5% when combined with the air discharge.The return airway control is below 0.3%,and the drainage effect is significantly improved compared with the previously adopted high-drainage gas extraction measures.The drainage of the protective layer not only solves the problem of gas accumulation in the goaf of the mining face,but also effectively solves the effects of,for example,the outflow of the goaf on the gas angle of the working face and the return flow.The extraction technology is simple,safe and efficient,and solves the problem of gas overrun in the upper corner and the goaf,and has high direct economic and social benefits,and has wide application value.