Development of a Rock Fragmentation Model for Using in Tunnel Blasts

Rock fragmentation due to blasting plays a crucial role in the total economics of mining, mineral processing and tunneling projects as it influences loading, transportation, crushing, and milling. In opencast blasts, various models have been employed as so to quantitatively predict fragment size distribution. Tunnel blasts, on the other hand, suffer from a lack of a reliable method of measuring rock fragment distribution. In this paper, an attempt has been made to develop such a model by the adjustment of the parameters used in conventional Kuz–Ram model and then the use of regression analysis. The new model was developed using 23 data sets gathered from four tunnels located in Bakhtiari dam, the world’s tallest double concrete dam which is under construction for providing power for a power plant with capacity of 1500 MW. To evaluate effectiveness of this model, the fragment size of four blast events has been compared with those of actual size obtained by image processing. The results of this study indicate that the new model with high correlation coefficient (R²) can be effectively used to predict rock fragment in tunneling projects where the main geology formation is made up from sedimentary rocks as the main source of aggregate used in construction.