Field evaluation of air-deck blasting for improving rock fragmentation at the Gol-e-Gohar no. ۱ open-pit iron ore mine, Iran

Rock fragmentation plays a critical role in the efficiency of downstream mining operations and in the overall economics of open-pit production. This study investigates the performance of air-deck blasting under full-scale production conditions at the Gol-e-Gohar No. ۱ open-pit iron ore mine, Iran. . It compares its results with those of conventional fully coupled blasting. Over two months, ۱۴ production blasts were analyzed, including ۷ conventional blasts and ۷ air-deck blasts selected under comparable geological and operational conditions. Fragmentation was evaluated using a consistent image-based analysis procedure, and key particle-size distribution indices, namely D۲۰, D۵۰, and D۸۰, were obtained from cumulative size distribution curves. In addition to fragmentation characteristics, operational performance was assessed through specific charge, specific drilling, blast-hole productivity, oversize fraction, muckpile condition, and shovel loading behavior. The results showed that air-deck blasting generated finer and more uniform fragmentation than the conventional method, with D۲۰, D۵۰, and D۸۰ reduced by approximately ۳۰.۰%, ۱۸.۶%, and ۲۰.۷%, respectively. The improved fragmentation also enhanced digging and loading conditions, leading to an approximately ۱۰% reduction in shovel loading time and a ۹% increase in blast-hole productivity. Statistical evaluation confirmed that the differences between the two blasting approaches were significant for the tested field dataset. In contrast, Split-Desktop-based statistical validation produced coefficients of determination (R²) in the range of ۰.۷۱-۰.۷۳ and RMSE values between ۸.۹% and ۱۰.۱%. Although the findings are site-specific and should be verified under different rock-mass and operational conditions, they demonstrate that air-deck blasting is an effective and practical technique for improving fragmentation quality and operational efficiency in open-pit mining operations.

کلیدواژه ها:

Air-deck blasting ، Rock fragmentation ، open-pit mining ، Image-based fragmentation analysis ، Blast design optimization ، Gol-e-Gohar iron ore mine