煤层综放初采高回收技术与顶煤促放效果验证

Verification of Initial Mining Height Recovery Technology and Top Coal Caving Promotion Effect in Coal Seam Fully Mechanized Caving

虎龙沟煤业采煤工作面初采中存在放顶煤块度大、回收率低等问题,造成煤炭资源浪费严重。根据矿井实际,设计了基于水力压裂技术回收方案,通过数值模拟分析促放后煤岩破断规律及顶煤运移情况,制定初采阶段水力压裂钻孔方案。结果表明:施工水力压裂钻孔后,煤岩界面形成水力裂隙,与原本存在的天然裂隙共同构成裂隙网格,改善了整体冒放性能;顶煤及基本顶裂隙发育良好,部分顶煤发育成网状裂隙结构;基本顶裂隙长度占裂隙总长的25%;与相邻的未压裂工作面进行对比,压裂促放后初采阶段顶煤平均回收率提高了42%,缩短了初次来压步距约30 m、周期来压步距约20 m,在一定程度上减小了支护工作阻力,降低了煤壁片帮与架间漏顶的概率。

During the initial mining of the coal mining working face in Hulonggou Coal Industry,there are problems such as large block size,low recovery rate of top coal caving and so on,resulting in serious waste of coal resources.According to the actual situation of the mine,a recovery scheme based on hydraulic fracturing technology is designed.Through numerical simulation analysis of the coal rock fracture law and top coal transportation situation after the caving promotion,a hydraulic fracturing drilling scheme is formulated for the initial mining stage.The results show that after constructing hydraulic fracturing drilling,hydraulic fractures are formed at the coal rock interface,which together with the existing natural fractures form a fracture grid,improving the overall caving performance;The top coal and basic top cracks are well developed,and some of the top coal develops into a network crack structure;The basic top crack length accounts for 25%of the total crack length;Compared with adjacent unfractured working faces,the average recovery rate of top coal in the initial mining stage after fracturing and caving promotion increases by 42%,shortens the initial pressure step distance by about 30 m,and the periodic pressure step distance by about 20 m,which to some extent reduces the resistance of support work and reduces the probability of coal wall caving and roof leakage between frames.