无底柱分段崩落法低贫化放矿数值模拟

分析了无底柱分段崩落法现行截止品位放矿的缺点，提出了低贫化放矿管理方法。与前者相比，该方法的特点是以一个回采区域为统计目标，上部回采时有意识的预留矿石，最后在最低水平集中出矿，从而减少矿石贫化过程。该方法在确保总回收率不降低的条件下，可以显著减少矿石的贫化率。以某金矿为例，拟定了8种低贫化放矿方案，通过离散元数值模拟，以回贫差作为优劣指标，对各方案进行了比较，最终确定了上面两个分段采用20%的矿石贫化率放矿，底下分段采用0.5 g/t的截止品位出矿时，回采指标最优。

Numerical Simulation of Low Dilution Ore-drawing of Non-bottom Pillar Sublevel Caving Method

The weakness of current ore drawing by cut-off grade in non-bottom pillar sublevel caving method is analyzed,the low dilution ore-drawing method is proposed.Compared with the former method,the characteristics of low dilution ore-drawing method is the ore in the upper sublevel is reserved consciously,the large number of ore is drawn in the bottom sublevel,so,ore dilution is reduced.The method of low dilution ore-drawing method can significantly reduce the ore dilution rate during ore-drawing,at the same time the recovery rate can be lowered obviously.Take a gold mine as an example,eight eight schemes of low dilution ore-drawing are proposed.Using the value of recovery rate minus the dilution rate for the indicator, the eight schemes are compared by conducting the discrete element numerical simulation.The results show that when the top two sublevels drawing by cut-off grade with 20% dilution,and the bottom sublevel drawing by cut-off grade of 0.5 g/t, the value of recovery rate minus the dilution rate is the highest indicator.