To address the absence of specialized explosives for mine presplitting blasting and excessive detonation velocity/power of conventional 32 mm emulsion explosives, this study proposed reducing the explosive diameter to moderate detonation characteristics. By combining critical diameter theory with numerical simulation analysis, a PVC tube charge model was developed in LS-DYNA. The detonation wave propagation was simulated using ignition-growth reaction-rate equations and fluid-solid coupling algorithms, with detonation-curve analysis verifying explosive stability. The BSS-1 intelligent ten-stage detonation velocity meter was employed to measure detonation velocities of emulsion explosives of different diameters, thereby enabling the determination of their critical diameter from experimental data. Results demonstrate strong agreement between simulations and experiments: stable detonation occurs at 14 mm diameter, while failure occurs at 12 mm, establishing the critical diameter range as 12 ~ 14 mm. Additionally, when the diameter exceeds 14 mm, the detonation velocity exhibits a positive correlation with diameter increase. This study, cross-validation of numerical simulations and field experiments, identifies the critical diameter range for industrial emulsion explosives in mining applications, offering empirical support for optimizing presplitting blasting parameters and enhancing safety management.

In order to realize the blasting demolition of 62.8 m high brick structure chimney in complex environment, various demolition options which fully consider the structure of the chimney and the surrounding environment were compared in the case of insufficient space for collapse on the east, west and north sides. After analysis, one-way and two-way folding blasting options were initially selected to blast and demolish the chimney. The circular angle of the upper and lower notch was designed as 220°. The lower notch was set as 2 m high at 0.5 m from the bottom of the chimney, while 30 m from the bottom of the chimney located the upper notch which parameters need to be simulated and optimized. ANSYS/LS-DYNA finite element analysis software was used to compare the collapse effect of the preliminary scheme, and it was calculated that the one-way folding blasting did not meet the demolition requirements, so the two-way folding blasting was selected. Then the chimney collapse process was simulated with the upper cut height of 1m, 1.5 m and 2 m and the delay times of 0.5 s, 1 s, 1.5 s, 2 s and 2.5 s between the upper and the lower cut. After analyzing the collapse process and the distribution range of the blast pile of the chimney under different working conditions, it was determined that the best folding effect with a small collapse space happened when the upper cut height was 1m and the delay time was 1 s. Furthermore, safety measures which were related to blasting vibration and flyrock protection were designed. The blasting effect showed that the chimney collapsed smoothly according to the designed direction during the blasting process, and no damage occurred to the surrounding buildings(structures). The overall blasting demolition effect was good enough to meet the expected goal. It can provide a reference for related scholars and demolition projects.

To investigate the effects of decked charge structure on the energy transfer and blasting outcomes, a study was conducted to improve the energy utilization rate of explosives and enhance the blasting impact based on the blasting operations of a limestone mine in Chenzhou. Combining LS-DYNA numerical simulations with on-site optimization experiments, this research examined the rock stress distribution across different charge structures during bench blasting. Simulations were performed on four charge structures: continuous charge, 0.6 m deck, 1.0 m deck, and 1.5 m deck, with effective stress monitored at key points. Field optimization experiments were then conducted using a novel transmissible explosive deck to analyze the overall blasting performance of the blast pile. The research results indicate that the rock damage extent and average maximum effective stress reach peak values at a 1.0 m deck length, resulting in favorable fragmentation. In field tests, the decked charge reduced the powder factor from 0.199 kg/t to 0.179 kg/t, lowered the fine ore rate by 6.54%, reduced the oversize rate by 3.7%, and increased the average block size by 5 cm. This approach minimized energy wastage and resolved uneven fragmentation issues with mixed emulsion explosives, enhancing the mine′s economic efficiency.