Optimization of blasting parameters for steeply dipping narrow gold veins

Abstract This study addresses the optimization of blasting parameters for narrow gold vein. A PFC2D numerical model was built based on an underground metal mine in China. A systematic simulation of blasting were conducted under 3 borehole layouts (square, zigzag, and quincunx) using 9 blast hole network parameters. The relationships among excavation ratio, fracture number, and peak particle velocity (PPV) at the free surface were studied. The findings show that the blasting effect is energy-dominated; Inadequate rock fragmentation arises from insufficient energy to fracture the rock mass when the number of fractures is less than 2800 and the PPV is less than 15 m/s. There is more underbreak when the weight or hole spacing is increased. A comprehensive multi-index study indicates the quincunx borehole layout as the ideal pattern, with the best parameters being a burden of 0.6 m and a hole spacing of 0.6 m. Field tests revealed that this improved technique results in regular blast cavity, homogeneous fragmentation, and near alignment with the planned contour. For the safe and effective blasting extraction of narrow veins when confined, this research offers a useful reference.