A physical modeling program was undertaken to assess and eliminate a significant vessel wear problem observed in a primary separation vessel used in the recovery of bitumen from oil sands. A 1:20 scale model was fabricated, and process rates and materials were selected on the basis of dimensional analysis. Experiments showed that the existing feedwell produced poor circumferential distribution and formed a localised jet that entered the vessel over a narrow sector. Tests were then conducted with several different modifications to the feedwell to improve the flow distribution. The final design produced uniform circumferential distribution and a modest improvement in model separation efficiency. This design has been in commercial service for several years and has eliminated the local wear problems.