Abstract: This invention is a method for recovering viscous hydrocarbonaceous fluids from a subterranean formation containing one or more vertically extensive, narrow, high permeability conduits. At least one injection well communicates with at least one production well via said conduits. Steam is injected into said injection well until the water-oil ratio becomes excessive at the production well. The production well is then shut in until the formation is pressurized. Stem injection is then stopped and the production well is opened for production by pressure depletion. This cycle is repeated until oil recovery becomes uneconomical.

Abstract: Method for separating a mixture of bituminous coal and a lower rank coal such as subbituminous, lignite, and mixtures thereof, comprising contacting the coal mixture with an effective amount of an aqueous chemical comminuting solution for a sufficient time to selectively comminute a substantial portion of one of the ranks of coal in the mixture. Thereafter, the comminuted coal and noncomminuted coal of different rank is separated from the chemical comminuting solution. The smaller comminuted coal particles of one rank are then separated from the larger noncomminuted coal of the other rank by screening. Substantially anhydrous methanol or an aqueous methanol solution is used to selectively comminute the bituminous rank coal whereas an aqueous alkaline solution, preferably aqueous sodium hydroxide, is used to selectively comminute the lower rank coal.

Abstract: Disclosed is a method for minimizing the entry of water into a mined cavity or underground formation which has thereabove a semi-permeable layer of a shaly material or rock directly below a source layer of water-saturated sand. By means of a borehole, a fluid such as air or oil is injected into a semi-permeable layer to displace water from it. The injected fluid acts as a barrier to reduce the downward leakage of water into the cavity.

Abstract: This invention is a process for comminuting run-of-mine crushed coal by contacting the coal with an aqueous methanol solution for a time sufficient to comminute a substantial portion of the coal to a predetermined particle size. Another aspect of this invention is a process for slurry mining coal which comprises contacting the coal in-situ with an aqueous methanol solution for a time sufficient to comminute a portion of the coal and to form a slurry, and then conveying the slurry to a receiving vessel where the comminuted coal is recovered. Still another aspect of this invention, is to transport the comminuted coal having a desired particle size in slurry form using an aqueous methanol solution as the slurry medium wherein there is further comminution of the coal to improve its burning characteristics.

Abstract: This invention is a comminution process for treating coal with a drying gas to form fractures which weaken the structure of the coal and make it easier to disintegrate mechanically, chemically or by fluid force. Another aspect of this invention is a process for treating an underground formation of coal with a dry gas for a time sufficient to form cracks and fractures in a portion of the formation in order to increase the permeability of the coal formation to the flow of fluids therethrough. Processes for in-situ combustion of the coal formation are therefore more efficient since the coal formation is more permeable to the flow of gas therethrough.