Abstract: To address the technical challenge of blast−induced dynamic damage to the adjacent 1880 m−level sublevel drifts during the transition from open−pit to underground mining in the Luodang mining area of Liangshan Mining Co., this study systematically investigated the dynamic disturbance mechanisms of surrounding rock masses under continuous column charges, axially decoupled charges, and radially decoupled charges. A comprehensive methodology integrating theoretical analysis, LS−DYNA numerical simulations, and field experiments was adopted. The results demonstrate that axially decoupled charges significantly reduce the dynamic response at critical positions of the drifts through the spatiotemporal interference effect of stress waves. The peak vertical particle velocity at the drift crown is reduced from 26.15 cm/s (with continuous column charges) to 14.50 cm/s, achieving a 44.6% reduction, which effectively satisfies the regulatory limits stipulated in the Blasting Safety Regulations. Numerical simulations further reveal that axially decoupled charges reconstruct the rock fragmentation mode via the superposition of multiple stress wave segments, resulting in a higher overlap ratio of the crushed zones compared to radially decoupled charges. Based on the threshold zoning control technique for blast epicenter distance (R ≤ 20 m as the critical protection zone), a synergistic optimization scheme is proposed, employing a 4.0 m × 4.0 m dense borehole pattern and 125 kg/hole axially decoupled charges. Under a constant specific charge of 0.65 kg/m³, field experiments validate that 81.28% of the blasted muck falls below 60 cm in size, with a boulder rate (>100 cm) of only 5.18%, and the vibration velocity in the drift is stably controlled below 15 cm/s. These findings provide both theoretical support and practical reference for the coordinated control of blast−induced vibrations and mining efficiency enhancement in open−pit to underground transition mining operations.