Document Type : Original Research Paper
Authors
1 Faculty of Mining, Petroleum & Geophysics Eng., Shahrood University of Technology, Shahrood, Iran
2 Department of Mining, Petroleum and. Geophysics, Shahrood University of Technology, Shahrood, Iran.
3 The Department of Mining and Geology of Research and Technology Management of Gol-e-Gohar, Sirjan, Iran
Abstract
Rock fragmentation induced by blasting plays a critical role in the productivity and cost efficiency of open-pit mining operations. Among blast design strategies, air-deck blasting has been proposed as a technique to improve energy utilization by modifying the pressure–time characteristics within the blasthole. However, its performance under production-scale conditions and the reliability of numerical predictions remain insufficiently validated. This study presents an integrated field–numerical investigation of air-deck blasting at the Gol-e-Gohar Iron Ore Mine No. 1, Iran. Fragmentation characteristics were quantified using image-based particle size distribution (PSD) analysis of muck piles processed with Split-Desktop software. Characteristic fragmentation indices (D20, D50, and D80) were extracted to evaluate blast performance. Three-dimensional numerical simulations were performed using the LS-DYNA explicit finite element code to model stress-wave propagation, damage evolution, and fragmentation development for both conventional blasting and air-deck blasting configurations. Numerical models were calibrated using site-specific blasting geometry, explosive properties, and rock mass parameters derived from field measurements. The results show strong agreement between numerical predictions and field observations, with coefficients of determination exceeding 0.95 and RMSE values below 10%. Compared with conventional blasting, air-deck blasting produced finer and more uniform fragmentation, reducing D50 by approximately 10–15% and D80 by up to 18%. The improvement is primarily attributed to stress-wave reflection at the air gap and enhanced tensile crack propagation. The proposed field-validated numerical framework provides a practical tool for blast design optimization and demonstrates the potential of air-deck blasting to improve fragmentation efficiency in large-scale open-pit mining operations.
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