Abstract: To obtain an optimized ore-drawing scheme with low ore loss and dilution in natural caving,the software REBOP was introduced to conduct three-dimensional simulation and loss-dilution prediction of multiple hopper drawing with regard to hanging wall,footwall and medium drawing in nickel mine.Results showed that an Isolated Movement Zone (IMZ) of nearly 70 m in height and an Isolated Extraction Zone (IEZ) of higher than 30 m were formed at drawing points after uniformly ore drawing for 30 days under three schemes.The ore-drawing percentages of hanging wall,footwall and medium drawing were sequentially 85.6%,85.4% and 85.7%,while the drawn ore grades were sequentially 0.56%,0.43% and 0.47%.Additionally,the maximal drawn ore volume and the ore grades of footwall were higher than that of other schemes,and drawn grades throughout the production period reached the designed grades,therefore the footwall drawing was selected as the optimized ore drawing scheme.

Key words: Caving, Loss-dilution prediction, Maximal ore-drawn volume, Optimization of ore drawing