Abstract
The performance of gravity-based coal-cleaning devices is customarily characterized by a generalized distribution curve, in which the amount of feed reporting to clean coal is plotted against reduced specific gravity. While several mathematical models in large varieties are there to describe the distribution curve, the need for a single generalized distribution model that can be used for all separation devices is recognized. However, the main challenge is to pick the right distribution model as the wrong selection of a model invariably can lead to conflicting results. Therefore, some deficiencies associated with the development of a generalized model are identified and discussed.