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在拉杰普拉-达里巴矿,老采空区的存在给浅部矿体的开采带来一些问题。在这种情况下,继续采用目前的分层充填法是不可能的。有鉴于此,建议采用分段崩落法开采这部分矿体。要用这种采矿方法回采现有分层充填法采场上部的矿体,而且不留任何顶柱。矿体的可采高度为40m,建议将矿体分成4个分段(矿块),每个分段高10m。数值模拟分析表明,如果各分段之间的超前步距保持4m,并且回采工作面线保持成一对角线,则分段崩落采矿法的回采作业是可以安全进行的。但是,如果超前步距增至8m,则最下部分段的稳定性就会受到威胁。在这种条件下,在最下部分段和紧靠其上的分段的接触面附近产生的张应力会导致岩体破坏。
At Rajputra-Dariba mine, the presence of an old goaf poses some problems for the mining of shallow ore bodies. Under such circumstances, it is not possible to continue with the current method of layering. In view of this, it is recommended to use sub-caving method to mine this part of ore body. This mining method is to be used for the recovery of the existing ore body in the upper strata of the stope by the existing stratified filling method without leaving any top pillar. The recoverable height of the ore body is 40m. It is suggested that the ore body be divided into 4 sections (nuggets), each section 10m high. The numerical simulation shows that the mining operation by the sub-level caving mining method can be safely carried out if the advance step distance between the sub-sections is kept at 4m and the working face line is kept in a diagonal line. However, if the lead step is increased to 8m, the stability of the lowest section will be threatened. Under these conditions, tensile stress generated near the contact surface between the lowermost segment and the segment immediately above it will result in failure of the mass.