Optimizing Rock Fragmentation Uniformity and Kinematic Control in Bench Blasting via the Normalized Decking-Rhodes Parameter (DRP)

Achieving a balance between effective rock fragmentation and the mitigation of hazardous flyrock (front-row throw effects) is a persistent challenge in open-pit bench blasting. This study investigates the influence of vertically positioned air-deck charges on explosive energy distribution and rock damage evolution. We propose the Decking-Rhodes Parameter (DRP) as a novel, normalized characterization index for air-deck positioning to replace qualitative descriptors. Using a coupled Particle Blast Method (PBM), Finite Element Method (FEM), and Smoothed Particle Hydrodynamics (SPH) numerical framework, complemented by field monitoring at the Husab Uranium Mine, we evaluate the DRP’s performance across varying burden conditions. Results indicate that optimal energy utilization and fragmentation uniformity are achieved when the DRP ranges from 0.36 to 0.73. Field applications confirmed that at DRP = 0.73, fragmentation met stringent gradation requirements while significantly reducing excessive top-bench throw.