Abstarct: In the present study, the energy consumption for rock fragmentation in Sungun mine has been investigated. In view of that, two rock zones of the mine were considered. The amount of energy for rock fragmentation in each zone was calculated using the model developed by Hamdy. In order to determine the Volumatic distribution of the in situ rock blocks, the geometrical properties of discontinuities and the number of joints in each zone were determined. Also, the probability distribution functions of the geometrical properties of discontinuities in each set of joints were specified. Then, the geometry, volume and Volumatic distribution of rock blocks were specified using 3DEC commercial code. In the next step, physical and geomechanical properties of the rock blocks were measured. In the final step, the size distribution of the fragmented rock blocks was determined using GOLDSIZE commercial code. According to the estimation model developed by Hamdy, the energy of rock fragmentation is related to the difference between the total surface area of the fragmented rock pieces and the total surface area of in situ rock blocks. So, the energy of rock fragmentation was measured using the geomechanical properties, Volumatic distribution of the in situ rock blocks and fragmented rock pieces. Results showed that in the dyke and mineral deposit zones, 13.6 and 9.6 percent of the total blasting energy is used for rock fragmentation, respectively. The rest of the energy is used for the catastrophic events such as earth quake, fly rock, etc. Furthermore, the evaluation the results showed that in the bigger rock block profiles (distancing, overburden), the amount of energy needed for rock fragmentation increases, which indicates that in the smaller rock profiles the energy dissipation is higher. In view of that, there must be an exact pattern of rock blasting and fragmentation in order to reduce the energy dissipation and gain desirable outcomes.