煤层群上保护层开采保护效果现场考察

摘要

In the mining process of coal group B with multi outburst coal seams in Xinzhuangzi Coal Mine,the mining method from top to bottom would lead to the decrease of effective protection region layer by layer and serious loss of re-coverable resource.According to the actual layout of the roadways,three suitable positions were selected to construct boreholes to investigate the gas pressure,gas content and coal seam deformation of trend and inclination in B6 coal seam,during the mining of 66208 working face.As results,the upper and lower pressure relief angles in the tendency of B8 coal seam were determined to be 79° and 86° respectively and the pressure relief angle of direction was 75°.All three pressure relief angles are larger than the theoretical value,which indicates that the actual effective protective region is extended.After the exploitation of B8 coal seam,the permeability coefficient of B6 coal increased by 902 times compared with the original coal seam,with the gas pressure and gas content dropping to the 0.22 MPa and 2.43 m3/t,respectively.So,the effect of eliminating outburst is remarkable.%针对新庄孜矿B组煤多层突出煤层开采过程中,大剥皮式的保护层开采方式造成保护范围逐层减小、可采出量严重损失等问题,根据巷道实际布置情况分别选择3个合适位置施工考察钻孔,对B8煤66208工作面开采过程中,B6煤层倾向和走向方向上的瓦斯压力、瓦斯含量和煤层变形进行现场考察.确定B8煤倾向上部、下部卸压角分别为79°和86°,走向方向卸压角75°,实际卸压角均比理论值大,保护范围也发生了扩界.B8煤层开采后B6煤的透气性系数相比原始煤层透气性系数增加了902倍,瓦斯压力和瓦斯含量分别降至0.22 MPa和2.43 m3/t,B6煤层消突效果显著.