Abstract: The deep open-pit mining project of the Qidashan Iron Mines is in the process of transition from the first phase to the second phase.However，the transition started late，it’s quite difficult to achieve stable transition.According to the current situation of mining and the distribution of the mine rock within the scope of the second phase，a geological model corresponding to the mine’s reality was established.With the use of the optimized production technology parameters，the practical situation of the hysteretic transition and the productivity of existing developing transport system were analyzed.Contrasting to the primary design of the stable transition to the second phase of deep open-pit mining project and based on the geological model built，three different stripping schedule programs and suggestions of development transport system were drawn up，and the reasonable depth of the stable transition was presented.Through analyzing the technical feasibility，an efficient and feasible production expansion of stable transition plan and a proposal of the mine production were determined.

Key words: Deep mining, Expansion, Stable transition, Scheme optimization