In the extraction of bitumen, from Canada's oil sands reserves, bitumen droplet coalescence is an important factor in determining the efficacy of the separation process. In a simplified analysis of bitumen droplet interactions, the relative contributions of classical DLVO and non-DLVO forces occurring between a bitumen droplet and surface-treated, planar, collector were evaluated using the impinging jet cell technique. Initial experiments were conducted using a system consisting of silane-treated silica particles an a hydrophobic collector. This. system is, known; to exhibit attractive non-DLVO interactions as was clearly demonstrated by the present,study. The attachment of bitumen. droplets onto two different-hydrophobic, collectors was then examined. Results of these experiments indicate that bitumen droplet interactions involve an additional repulsive force that may be attributable to the heterogeneous nature of the droplet surface.