Numerical Analysis of the Pile Movement Resulting from Rock Blasting in Open Pit Mines

Pile movement is one of the rock blasting outcomes that, considering the type of haulage machines, has a direct effect on the efficiency of the loading process. In this study, using UDEC discrete element software, the pile movement of fragmented material caused by the blasting operation is modeled. Since UDEC is not capable of modeling the whole process of rock blasting, to accurately model the pile movement of fragmented material, the damping coefficients must be changed in a way to allow the move freely out of the split blocks after the blast, be modeled. The numerical modeling results show that implementing a negative exponential function with three (the initial, threshold, and power) eigenvalues, as the fish-function to the damping coefficient, can model the results pile movement. With the help of this damping function, three blasting blocks with one and two rows of blast holes were modeled. The results of these modeling show that the pile movement for the two rows of blast holes depends on the inter-row delay time, and for the delay times of 17 ms and 50 ms, the maximum horizontal movement of the pile was 30 m and 55 m, respectively. These values show good agreement with the values measured in an actual blast operation. The results of this study show that by changing the negative exponential function eigenvalues defined for damping, the velocity of the fragmented blocks, the displacement, and the geometry of the pile, could be modeled. This shows the capability of the discrete element method in the modeling of the results of rock blasting.