In this paper we focus on recent developments in DEM modelling of tumbling mills. Examples of 3D models of SAG mills are presented along with detailed predictions of power draw, liner wear rates, liner stresses and energy spectra. Comparisons of simulation results with photographs of charge motion in a scale model SAG mill demonstrate a high degree of accuracy. The inclusion of particle breakage in the DEM is demonstrated as is the methodology for predicting breakage rates, mill throughput, and equilibrium particle size distribution of the charge. Finally, the variation of power draw with liner shape throughout the lifter life cycle is illustrated.