Pressure drop and concentration distribution studies for the flow of multi-sized solid-liquid flow through slurry pipelines has been carried out over a wide range of efflux concentrations and mixtures of solids having different particle size distributions. The particle size effect on pressure drop has been analyzed through the measured solid distribution pattern in the pipeline. An integral flow model has been used for prediction of the pressure drop and solids distribution under various conditions. The model has been used to predict the optimum particle size distribution that gives the minimum specific energy consumption. (C) 2003 Elsevier Science B.V. All rights reserved.