At the end of the open-pit mining process in large metal mines, the mining model must change from open-pit mining to underground mining, but the mutual interference between the two mining models leads to poor production safety conditions and difficulties in production convergence during the transition period. To solve these technical problems of poor production safety conditions and difficulties in production convergence during the transition period, in this study, based on the case of the Dagu Mountain Mine, a new transition mode of wedge switching for collaborative mining is proposed and established, which is suitable for collaborative mining. This new mining process completely eliminates the boundary pillar and the artificial covering layer, combining the technology of the mining-induced caving method and the technology of deep mining at the bottom of the open-pit. The results show that 1） the optimization of the open-pit boundary reduces the amount of rock stripping, and 2） it achieves a stable transition of collaborative mining capacity. The study shows that the proposed method uses the technologies of the mining-induced caving method in underground mining and deep mining at the bottom of the open pit in open-pit mining, and the method then optimizes the open-pit mining in detail by comparing the advantages of open-pit mining and underground mining. This study provides true and accurate technical support for the transition from open-pit mining to underground mining.
