| To solve the problem of gas governance in seam group ascending mining of upper seam mining, basing on the actual mining coal group circumstances of the 11 th mining area of Jin Jia colliery, using the theoretical analysis, numerical simulation, field test and measurement methods, analyzed after the first mining No.22 seam mining overburden rock fissures and relief regular of coal mining host No. 18-1, and the gas transported relief move regular and rich region, combined with the actual conditions of the mine gas drainage engineering practice. Specific research results are as follows:This paper has combined with the similar simulation experiment results to analysis the failure modes of overlying strata, overlying rock collapse and separation crack distribution of the host No. 18-1 coal mining process, inferred the maximum height of collapse and fracture zone as 8m and 31 m respectively, calculated the height interval 6.9 ~ 9.2m of the caving zone using the empirical formula with value when upper coal seam mining, with highly fractured 32.4 ± 5.1m.Basing on the mining geological conditions of Jin Jia colliery, this paper has maden the use of numerical simulation software FLAC3 D to simulate the mining process of first coal mining on the 22 nd of postharvest host No. 18-1 coal, analyzed overburden stress of the upper vertical as well as the distribution of plastic zone overlying strata, found that stress concentrating area is on the face, eyes open and cut into the back alley near the wind, moving forward with the mining advance at the working surface area. Plastic region overlying rock increases with mining depth gradually, tested in the strike and dip rounded trapezoid.The paper analyzed the upper coal seam relief gas migration pathways. Using the numerical simulation software FLUENT to simulate gas migration regular in fissure zone of stope, to contrast and analysis the gas concentration of different drainage conditions stope regional. The results has showed the upper corner gas concentration could be higher only a U-shaped lower ventilation;The gas concentration was significantly reduced when increased the drainage of pipe on the corner return airway. It indicated that gas drainage pipe on the return airway could better solve the problem on the corner gas accumulation. Under the conditions of U type ventilation and bottom drainage roadway to drainage, the gas concentration of mined-out area declined, indicating the bottom drainage roadway to drainage has good treatment effect on gas emission of stope extraction fractured. The integrated use of the return airway has been buried with bottom drainage pumping lane which could be a very good way to solve the problem of gas emission on the face upper coal mining. To further enhance the effect of extraction,it still needs to add a high drilling and some other ways to bring crack stope extraction ministry emission gas. According to the distribution of relief regional and the regular of relief gas moving, established engineering model of mining crack and relief gas rich region anout upper coal seam.Using sub source method to predicting the 11 group number 18-1 seam mining gas emission quantity in Jin Jia colliery, this paper selected several methods of gas comprehensive govern technology as bedding drainage of the coal seam gas drilling, bottom lane pumping gas drainage under near layer, high drill field and internal borehole layout, bottom Lane pumping and drainage pipe gob gas on return airway. The paper inspected the gas concentration in return airway during the face advancing, the gas drainage concentration, the volume and efficiency of gas drainage. The results show that: the return airway ventilation air methane concentration averaged within 0.35 percent, roadway drainage bottom pumping gas concentration averaged of 13.58 percent, leaving the tube drainage concentration averaged of 5.78 percent and the amount of gas drainage pipe averaged of 9947m3 /d. 111811 Work Face during mining gas pumping rate averaged between 70.33%-89.22%. |
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