Abstract: In a hot water process for extracting bitumen from tar sands comprising forming a mixture of tar sands and water, settling the mixture in a primary extraction zone to form an upper bitumen froth layer, a middlings layer, and a sand tailings layer, passing a part of the middlings layer to an air scavenger zone to recover additional bitumen therefrom, the improvement which comprises aerating the mixture of tar sands and water before separating bitumen froth from the mixture in a gravity settling zone. This aeration can be accomplished by adding an aerated recycle middlings stream to the tar sands water-mixture prior to the settling step.

Abstract: A method for reducing the sludge layer in an effluent retention pond associated with hot water extraction of bitumen from tar sands comprising recycling sludge from the retention pond to aid in removing the aqueous effluent discharge from the extraction process and thereby effect a reduction of the volume of the sludge layer in the pond.

Abstract: A method for improving recovery in a hot water process for extracting bitumen from tar sands comprising adding bitumen-depleted middlings recovered from a scavenger zone to the sand layer in a primary extraction vessel at a point below the surface of the sand.

Abstract: An environmentally attractive method for storing sludge containing water, mineral matter, bitumen, and liquid hydrocarbon formed in a retention pond used to store effluent discharge waste streams associated with aqueous extraction of bitumen from tar sands comprising inserting the sludge below the surface of an unpolluted pond.

Abstract: In the delayed coking process wherein hot coke is formed by destructive distillation of a petroleum feed in a coking drum to provide solid coke and distillate petroleum products, the method of regulating the rate of quenching the hot coke after the drum is full and coking has ceased which comprises regulating the rate of feeding quench water to the coking drum in accordance with the internal pressure measured within the drum.

Abstract: The specification discloses an apparatus for recovering bitumen from large water surfaces. The apparatus comprises a crowned continuous conveyor belt with screen-bottomed scoops spaced along the outer surface of the belt.

Abstract: A method for reducing the sludge layer in an aqueous effluent retention pond associated with hot water extraction of bitumen from tar sands comprising dispersing the aqueous effluent discharge from the extraction process containing bitumen, sand, water, silt and clay over the surface of the pond thereby effecting a reduction in the volume of the sludge layer in the pond.