Abstract: A method of extracting bitumen from a subsurface tar sand bed wherein a shell of frozen earth is formed around the periphery of at least a portion of the tar sand bed, followed by recovering bitumen from such portion of the tar sand bed within the shell of frozen earth by suitable means such as, for example, solvent extraction. Also disclosed is apparatus for freezing the earth surrounding one of a plurality of boreholes drilled in the earth within earth freezing distance of each other around the periphery of such portion of the tar sand bed.

Abstract: Particulate materials are blended in a vessel provided with a plurality of vertically extending conduits therein. The vessel comprises a downwardly converging frustoconically shaped bottom wall which defines the lower region of the vessel. The lower ends of the conduits extend through corresponding openings in the bottom wall and are connected by suitable conduit means with a solids outlet at the open bottom of the bottom wall, an outlet conduit extending downwardly therefrom with a solids flow control valve interposed therein. A recycle conduit extends from the interior of the outlet conduit at a position above the solids flow control valve therein upwardly to a solids hopper positioned above the vessel. A blower is connected to the upper portion of the vessel and applies vacuum thereto and to the recycle conduit for withdrawing particulate materials or solids through the recycle conduit into the hopper.

Abstract: 1. Normally solid polypropylene, consisting essentially of recurring propylene units, having a substantial crystalline polypropylene content.