An Empirical Model to Predict Particle Size Reduction Caused by Blasting in the Conglomerate Rock-Mass at Gotvand Olya Dam

The main aim of blasting operations in mining and civil engineering projects is size reduction of the rock-mass. Particle size reduction (P.S.R) affects the efficiency of the loading, haulage and milling equipments. Therefore, prediction of mean fragment size in designing optimum blasting patterns is crucial. In this research, a model is presented for predicting mean fragment size caused by blasting, using a combination of Grady & Kipp model (considering the number of radial cracks in the vicinity of the blast-hole) and concept of the mean fragment size. The proposed model shows that mean fragment size is a function of rock-mass characteristics, fracture toughness (KIC), explosive characteristics such as velocity of detonation, specific density and geometrical blasting parameters like burden, spacing, blast-hole diameter, etc. Considering validation of this model at the rock-fill mines of Gotvand Olya Dam, in real-scale, application of this model is recommended in open-pit mines blasting.