Field Application of Mixed Emulsion Explosives with Decked Charge Technology in an Open-pit Mine

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.