Abstract: The cone elimination method was used to generate the maximum boundary based on established numerical model of ore deposits considering slope angle and technical economic parameters.On the basis of the geological optimum candidate boundary sequence produced in the maximum boundary， five groups of staging ore volume were set up. By comparing the staging number， the amount of ore and rock in staging boundary， the net present value and the time span of each stage， the influence of staging ore volume on boundary optimization was analyzed. The optimization results showed that the lower limit of the staging ore volume remains unchanged and the upper limit increases， the staging number decreases from 9 to 8.The fluctuation of the mining amount and the rock stripping amount in the staging boundary mainly occurs in the first few stages. The total net present value has been increasing，however the increase is gradually decreasing. The lower limit of the staging time span is unchanged， the upper limit is gradually increasing. According to the total net present value and the staging time span， staging ore volume in 6~9a or 6~10a is more suitable to improve economic efficiency.

Key words: open-pit mine, boundary optimization, installment mining, staging ore volume, numerical model of mine deposit