Abstract: The development trend of the pillarless sublevel caving method is to increase the structural parameters and therefore, many existing mines have to confront with the transition of the stope structural parameter from the common space to a larger space.With Jinshandian Iron Mine as the case, in view of the ore drawing problem in the transition sublevel and guided by the pillarless low dilution drawing theory, it is suggested to comprehensively consider the optimized ore drawing mode of multiple sublevels and to find a corresponding caving space.On this basis, the optimal drawing measures are put forward, including the blast optimization, the ore drawing management and the control of the cut-off drawing grade.

Key words: Pillarless sublevel caving, Stope structural parameters, Transition sublevel, Ore drawing mode