A modified Suspension-Partition Model has been developed to predict partition curves of the smaller particle size fractions from experimental data of density tracer rest at large particle sizes in dense medium cyclones. In this model, the sedimentation pur caused by a centrifugal farce is balanced by the turbulent diffusion flux. In addition, medium segregation and the dependence of particle diffusivity on particle size are also taken into account in the model. Three model parameters are estimated by fitting experimental data for a large particle size fraction to the model, and the model can be then used to calculate partition curves of the smaller particle size fractions. The capacity to predict the partition coefficients of finer particle sizes is demonstrated in a number of examples. The benefit of using this improved mathematical model is a cost reduction in the experimental determination of the performance of a given dense medium cyclone.