It is quite common to encounter discrete element method (DEM) simulations of mills that present images, of the motion of grinding media, summaries of tangential and normal forces, and mill power. The usefulness of this data is questioned, with respect to modelling breakage. This work presents hypotheses of how the DEM simulations can be used as input to comminution modelling, and this guides the data logging and analysis requirements. Techniques are proposed for collecting and using this data in a manner useful for predicting breakage in a comminution device. Individual particle impact histories of contact angle, force, and impulse are required to realistically model breakage. It is argued that the majority of breakage results from cumulative damage, thus it is essential to track individual particle histories to realistically predict the breakage product from a mill. (c) 2006 Elsevier Ltd. All rights reserved.