In order to develop a better understanding of the role of the froth phase in coal flotation, froth stability measurements have been conducted using a continuous flotation cell. The results indicate that the mass flow rate of coal or mineral matter reporting to the product is linearly related to the flow rate of water reporting to the product. This relationship has been used to distinguish the relative contributions of hydrophobic attachment or hydraulic entrainment to the total product recovery. Simple mathematical expressions have also been developed to characterize the cleanability of various coals. A mathematical model based on first principles has been developed to provide additional insight into the complex relationship between the various operating parameters of a flotation cell and the froth behavior. The predicted results compare favorably to actual flotation test data for most conditions. In addition, a simple method was developed to study the fundamental interactions of various frothing agents with coal particles. The results of these studies indicate that the adsorption behavior of frothers in the presence of coal depends on both the physical properties of the frothing agent and the coal. / Master of Science