Abstract: 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.

Key words: Low dilution ore-drawing, PFC, Numerical modeling, Difference of the recovery and dilution