A model based on the potential energy minimization principle allowing for the dispersive effects due to panicle-particle and particle-fluid interactions is developed and applied to the jigging of coal. The model requires only a single parameter, the specific stratification constant. The model generates the equilibrium stratification profile for all components in the jig bed and the separation of each component is then calculated as a function of the total yield of solids. The model is validated against experimental data obtained from a laboratory batch jig and against operating data from several industrial single and two-compartment Baum and Batac jigs. The model calculates the performance of continuous jigs for arbitrary compositions of the feed and is paticularly useful for the reliable simulation of washing plant performance.