Influence of drift width on ore drawing effects in non-pillar sublevel caving method

The structural parameters of non-pillar sublevel caving mining method have great influence on the loss and dilution of ore drawing.The drift width effecting on the amount of drawing-out ore, recovery and dilution rate is studied via using an ore drawing model with single sub-level and single drift, the ore drawing effects are also analyzed.The experiments find that the amount of ore released within the same caving step is obviously increased when the drift width increases, and the phenomenon of ore arching at the eyebrow line of the intersection is also greatly reduced; the fluidity of ore could is improved by increasing drift width, when drift width increases for each 0.5 m, the increasing of ore recovery rate is about 1.3%; with the increasing of drift width, the ore dilution is delayed by time and the increasing of dilution rate is slowed down, but the final dilution rate shows a small increasing trend.The research results show that the main reasons of the ore drawing effect changing is that increasing the drift width can improve the amount of ore and rock between the two sliding (or moving) surfaces, thus improving the amount of drawn-out ore; the re-disturbed range of ore and rock is decreased, the speed of waste rock mixing is slowed down with the increasing of the width of drift during the ore drawing process.