A feedwell system for delivering a slurry (for example a bituminous slurry) to a separation vessel (for example a primary separation vessel) includes a feedwell barrel with an inlet for receiving the slurry, internal baffles, and a bottom outlet. A downpipe extends from the bottom of the barrel directing the existing slurry onto a deflector plate deflecting the slurry radially and outwardly. A protector plate located between the downpipe and the deflector plate improves the underwash layer stability. Ventilation openings in the protector plate induce inflow which reduces the discharge velocity, limits the formation of an adverse pressure gradient and encourages circumferential distribution.