Abstract: If Baiyunebo East mine can rationally develop and utilize resources outside the boundary, it will be able to continue the mine life cycle.This paper analyzes the mining plan of the resources outside East mine from the aspects of technical feasibility and economic rationality.It is found that the underground mining is the only option for the exploitation of resources outside East mine.Based on the application of Dimine digital mine software to establish the 3D geological model of the East mine, the underground mining division is studied according to the shape of the ore body, the distribution of resources and the relative position with the open pit.In order to realize the convergence of East mine open to the underground non-stop production:the outer boundary of the southern boundary is opened in the open pit, and the mining in the northeast boundary is subsequently implemented.The final implementation of mining is outside the open pit.The recovery of the external ore body in the open pit mine not only fully recovers the national mineral resources, but also provides a new way for the sustainable development of open pit mines.