Transportation of coarse coal, up to a size of 7 mm, in a fine-coal slurry medium with a particle size < 150 mum has been studied up to 58% by wt of the overall concentration in a 50 mm dia pipeline. A model has been established for calculating the yield stress with respect to the addition of coarse particles to a fine-particle slurry by analysing the laminar slurry flow. For the turbulent flow, an equation has been developed to predict the pressure drop accurately.