A model based on the Discrete Element Method (DEM) was used to simulate various types of mill (ball mill, centrifugal mill and vibration mill). The model is capable of describing the motion of balls and predicting the types of force between ball and ball, and ball and wall. In the case of ball mill, it was found that the movement of balls was mostly cascading type at the low speed, and at the speed beyond the critical value, the movement of balls was mostly centrifugal. Also, it was found that the movement of balls mainly depends on the lifter design of the mill. In the case of centrifugal mill, the operation characteristics of the mill were observed with the change of G/D (gyration diameter to mill diameter). The result of the simulation showed that the ball movement was similar to that of vibration mill at a low G/D ratio, and that of planetary mill at a high G/D ratio. In the case of vibration mill, different patterns of ball movements to the various ball filling conditions were observed and there was a linear relationship between impact energy and specific rate of breakage. The developed 3-dimensional DEM model can provide the ways of improving the energy efficiency and the operating at the optimum milling conditions.