崩落法分区交界矿体连续开采技术

Continuous Mining Technique for the Orebody at Sub-regional Intersection under Caving Method

小汪沟铁矿采用分区崩落法,沿矿体延深方向分为上、中、下3个采区同时开采,分区交界部位的采区矿柱受采动应力的长期作用,在距离空区边界15~25 m的范围内,产生了破损程度不等的采动裂隙,由此导致凿岩夹钎,增大了采准工程的施工与回采难度。总结上、中位采区矿柱回采经验,基于散体柱支撑理论,依据采空区冒落线接近于拱形及陷落角内倾的现场监测结果,对临空高度大、承压时间长的中、下位采区矿柱,研究提出钻孔探测空区边界、调整回采顺序与回采进路方向、增大巷道支护强度等综合技术措施,适应采动裂隙条件,使崩落法分区交界难采矿柱得到了安全连续回采。

The sub-regional sublevel caving method was adopted in Xiaowanggou Iron Mine,which is divided into upper,middle and lower mining areas for simultaneous extraction along the direction of ore body.Under the long-term mining disturbance on pillars at the intersection of sub-region,the mining-induced fractures with different damaged condition were generated within the limits of 15~25 m from the boundary of mined-out area,resulting in the drilling pinching and increasing the difficulty of mining construction and recovery in the quasi-mining project.Summarizing the experience of pillar mining in upper and middle mining areas,based on the theory of loose pillar support,and according to the field monitoring results of the caving line at goaf approaching the arch shape and the inclination of the caving angle,the comprehensive technical measures of detecting the boundary of goaf by drilling,adjusting the mining sequence and the direction of mining approach,and increasing the support strength of roadway are put forward for the pillars in the middle and lower mining areas with high goaf height and long bearing time.These measures adapts to the mining-induced fissure condition,and makes the pillars at the boundary of caving zone safe and continuous mining.