宽煤柱窄条带点柱式充填开采技术与实践

Technology and practice of point-pillar back-filling mining with wide coal pillar and narrow strip

针对某煤矿地下水保护的需要,提出一种宽煤柱窄条带点柱式充填开采技术。为成功实现条带式保水煤层开采,首先,分析条带开采时煤柱的留设;其次,分析了充填方法后,结合煤矿的充填材料来源,提出膏体充填工艺及流程;最后,对充填效果评价指标接顶率分析,提出点柱式充填加强支护效果。开采块段采用单翼长壁法布置充采双工作面,并形成全风压通风系统,在工作面内平行于切眼方向划分数量不等的宽煤柱,每个宽煤柱安排不同轮次的窄条带进行回采。条带开采后实施沿空留巷,采空区(回采后的窄条带)实行点柱式充填法与完全充填法相间的方法处理,第一轮与第二轮采用点柱式充填法、第三轮与第四轮采用全部充填法管理顶板。采用数值模拟分析,对充填后地表最大下沉量进行了预判与分析,地表最大下沉量发生在采区中部,为106mm,现场地表沉降监测数据和理论计算结果相吻合。研究成果在煤矿现场得到了应用,实现了地下水资源保护性采煤,提高资源回收率,降低充填成本,减少地表沉降。

Aiming at the need of groundwater protection in a coal mine,a point-pillar back-filling mining technology with wide coal pillar and narrow strip is proposed.In order to successfully realize the strip water retaining coal seam mining,the retention of coal pillar during strip mining is analyzed.After analyzing back-filling methods,combined with the source of back-filling materials of the mine,the paste back-filling technology and process of the mine are put forward,the top connection rate of the back-filling effect evaluation index is analyzed,and the point-pillar back-filling is proposed to enhance the support effect.The single wing long wall method is adopted to arrange the back-filling and mining double working faces in the mining block,and total pressure ventilation system is formed.In the working face,different numbers of wide coal pillars are divided parallel to the cut-off direction,and each coal pillar can be mined with different rounds of narrow strips for mining.After strip mining,the roadway along the goaf shall be retained,the goaf(narrow strip after the stoping)is processed by the alternate method of point-pillar back-filling and complete back-filling.The roof is managed by point-pillar back-filling in the first round and the second round,and all back-filling in the third round and the fourth round.The numerical simulation analysis is used to predict and analyze the maximum surface subsidence after back-filling,the maximum surface subsidence occurs in the middle of the mining area,and its maximum subsidence is 106 mm,which is consistent with the monitoring data of on-site surface subsidence and theoretical calculation results.The research results have been applied in the coal mine site to realize the protective mining of groundwater resources,improve the resource recovery rate,reduce the back-filling cost and reduce the surface settlement.