Cone crushers are used in the aggregates and mining industries to crush rock material. A model was previously developed to predict the worn geometry of a cone crusher. In that model there was some disagreement between predicted and measured geometry. A suggested explanation for the discrepancy is that the flow model used is not accurate enough to predict the pressure and wear on the liners. In this study an alternative flow model is presented that is better adapted for pressure and wear prediction. In the new model, the same mode of motion as in the old model is assumed to occur but only below the choke level of the crusher. Above the choke level it is assumed that downward flow is stopped by other particles that are squeezed further down. To determine the size distribution and bulk density above the choke level, an iterative process was necessary. Simulation results show that the new flow model has improved the accuracy in the prediction of operating parameters of the rock crusher, such as hydraulic pressure, power draw, and close side setting, CSS. There is also some improvement of the prediction of worn geometry as compared to the old model. (C) 2004 Elsevier Ltd. All rights reserved.