Abstract: An improved method and apparatus for preparing and oil sand slurry. Mined oil sand ore is deposited into a rotatable breaker tube. As the rotary breaker rotates, the ore is advanced and broken. Process fluid may be differentially distributed throughout the length of the rotary breaker, forming an oil sand slurry and assisting in the comminution and ablation of the ore. The comminuted oil sand and process fluid passes through perforations in the interior surface of the rotary breaker, and are collected in a hopper below, while oversized ore lumps are ejected out of the discharge end of the rotary breaker. The rotatable breaker tube is resistant to backflow at higher infeed rates.