Analysis of Effects of Detonation Velocity and Stemming Length on Muck Pile Blasting Performance

This study investigates the mechanism by which detonation velocity and charge length influence blasting performance in muck pile blasting, aiming to optimize blast design parameters while enhancing explosive energy utilization efficiency and operational safety. By establishing a comprehensive evaluation system integrating fuzzy mathematics, the entropy weight method, and the analytic hierarchy process, this study analyzes the optimal ranges of detonation velocity and charge length that meet field construction requirements. Additionally, a mechanical model of muck pile blasting was developed using the discrete element software PFC. The study systematically examined stress wave propagation, fracture propagation, and energy transfer characteristics across various combinations of detonation velocity and stemming length. Field measurements of critical parameters, including blast vibration parameters, rock fragmentation distribution, and muck pile morphology, were conducted and cross-validated with simulation outputs, confirming both the engineering adaptability of optimal parameter ranges and the reliability of numerical modeling predictions. The experimental results demonstrate an optimal detonation velocity range (approximately 4500 m/s) for bull emulsion explosive in muck pile blasting operations, showing optimal compatibility with granite formations. Below this critical velocity threshold, insufficient explosive energy occurs, leading to increased oversize fragment generation in blasted rock masses. Excessive detonation velocities lead to elevated fine ore production rates due to disproportionately high peak stress-wave pressures. Furthermore, a critical correlation exists between charge length and bench height. Optimal fragmentation balance between the upper and lower bench sections is achieved when the charge length is 20% to 26% of the total bench height. Through targeted technical interventions, refined blasting implementation, and optimized adjustment of explosive detonation velocity coupled with charge length, significant enhancement of bench blasting performance can be achieved under existing burden and spacing. This research elucidates the coupling mechanism between detonation velocity and stemming length, establishing both theoretical foundations and practical guidelines for optimizing blasting parameters in open-pit mine muck pile blasting.