无底柱分段崩落法多端壁倾角下崩矿步距优化

分析了崩矿步距优化的原则,确定以"回贫差最大"作为最优指标判据,以端部放矿实验为手段来测绘该结构参数下的放出体形态,利用实验获得的形态参数,计算崩矿步距的最优范围,辅助"相似矿山类比法和经验法",最终确定崩矿步距的最优范围为3.6~4.8 m.此外,考虑端壁前倾对降低贫化率和废石混入率具有较好的效果,参照国外生产矿山实际应用,以1∶50相似比开展了端壁倾角为80°,85°,90°条件下最优步距范围内3.6,4.0,4.4,4.8 m的放矿步距相似实验.实验结果表明,步距4.4 m,倾角90°方案对应的参数为梅山铁矿18 m×20 m条件下最佳结构参数.

Optimization of Caving Space for Different Angles of End-Wall During Pillarless Sublevel Caving

Based on the principle for optimizing the caving space,the optimal index in line with "the maximum difference between the recovery ratio and dilution ratio" was determined,and the shape of ore-rock mass drawn down with these structural parameters was measured using side drawing approach.According to the shape parameters of ore-rock mass drawn down,together with the analogy method among similar mines and the empirical method,it was determined that the optimal caving spaces range from 3.6 m to 4.8 m.Besides,it was suggested that the end-wall leaning forward may be helpful in decreasing the dilution ratio and reducing the mixed waste rock.In accordance with the practice of foreign operating mines,the similar experiments of drawing space under the similarity ratio of 1∶50 were conducted,and it was determined that the optimal drawing spaces are 3.6,4.0,4.4 and 4.8 m at the end-wall angles of 80°,85°,90°,respectively.The experimental results indicate that the optimal caving space for Meishan Mine is 4.4 m and the end-wall angle is 90° when the structural parameters are 18 m×20 m.