斌郎煤矿401采区预抽瓦斯试验及治理利用建议

Gas pre-drainage experiment and treatment& utilization scheme of 401 mining area of Binlang Coal Mine

基于斌郎煤矿401采区瓦斯地质情况,参照相关规范计算并预测了采区瓦斯储量和瓦斯涌出量,预测值分别为15.08 Mm3和7.84 m3/min,以此为依据初步分析确定了该采区抽采瓦斯的必要性与可行性。为进一步掌握煤层预抽瓦斯的可行性,在401采区北端沿内连煤层掘进1条长度为309 m的瓦斯专用巷道。通过在±0西北大巷实施穿层钻孔和在采区内连煤层掘煤巷道实施顺层钻孔2种钻采方式,进行了采区瓦斯预抽试验。试验共实施了6个穿层孔和6个顺层孔,临孔间距分别为6 m和5 m,测得12个孔的平均单孔瓦斯流量和平均瓦斯体积分数分别为0.091 m3/min和47%,获得了较好的瓦斯预抽效果。综合分析采区瓦斯主要参数的预测结果和瓦斯预抽试验数据,提出了"以首先开采外连煤层并同时抽采内连煤层的卸压瓦斯为主,必要时预先抽采煤层瓦斯和围岩裂隙中瓦斯"的采区瓦斯治理方案和将U型通风变更为Y型通风的建议。参考相似矿井的瓦斯利用经验对瓦斯发电的投入及产出进行了预算和评估,将发电机功率初步确定为500 kW。

The paper is inclined to present our investigation over the ways of the gas pre-drainage experiments, the treatment ＆ utilization scheme of 401 mining area of Binlang Coal Mine. Based on the investigation, we have made our estimation on the basis of our observation of the geological conditions of 401 gas-tapping area of Binlang Coal Mine, its gas reserves and emission of the surrounding mining area. In the process of our calculation of the above said two gas parameters, we had widely referred to the similar corresponding home coalmine gas drainage standards and confirmed quite some coefficients so as to collect as much information as the geological conditions as for the gas reserves. What we have made sure is that the predicted gas reserves and emission results of this mining area are 15.08 Mm^3 and 7.84 m^3 /min. By conducting the comprehensive analysis of the existing research before any treatment measures, we have made necessary and feasible gas extraction schemes. Thus, before gaining further grounds to identify the feasibility of the gas pre-drainage measures, we had excavated a 309-meter-long specific coal drift along the underneath coal seam in the north of 401 mining area. Then the pre-drainage gas experiment was conducted by drilling through the beds holes from the ±0 northwest main roadway and drilling in-layer holes from the specific coal drift. All in all, we have drilled 6 through beds holes with the hole interval of 6 meters and 6 in-layer holes with the hole interval of 5 meters, with the average gas flow rate and bulk fraction of the total 12 gas holes being 0.091 m^3 /min and 47% respectively. The results of the main gas parameters＇ prediction and pre-drainage experiments tell us that the final gas treatment should be done in the following steps： （1） the gas from the underneath coal seam should be drained when the upper seam is exploited; （2） in case it is necessary to pre-drain the gas from the coal seams and the fractures of surrounding rocks, pre-drainage has to be done; （3） if necessary, reliable ventilation should be achieved by changing the ventilation mode from U-type to Y-type. In addition, we have made an assessment over the investment and profit of gas power generation by referring to the experiences of some similar coal mines, so as to select the preliminary capacity of electric generator as 500 kW for the use of the extracted gas.