Abstract: A process is provided for the recovery of hydrocarbons, and especially heavy hydrocarbons, from oil-bearing strata, wherein mining liquids are injected at a bottom level and removed at an upper collecting level together with displaced liquid hydrocarbons, and the mining liquids are separated from the product hydrocarbons at the well-head and re-injected. The mining liquids may consist, in part, of an unrefined fraction from product cracking or semi-refining carried out in the vicinity of the well head, together with inorganic solvents, and are injected under pulsating pressure at a temperature not exceeding 100.degree. C. The strata can be deliberately fractured horizontally at the injection and collecting levels to promote desirable flow patterns, the fractures being propped open by means of a particulate filling medium. Hot gas under pressure can be injected at the boundaries of the working zone to create barriers to flow by the melting and re-solidifying of heavy hydrocarbons.

Abstract: The present invention comprises a method of mining a solid substance, such as coal, minerals, or the like, from an underground deposit in one of a plurality of earth strata. Void areas are created in the deposit so as to generally define an area within the deposit which is to be enclosed. Plugging material is injected into the void areas to form a relatively impervious barrier enclosing the aforementioned area of the deposit and isolating it from the remainder of the earth strata in which it is located. Conversion media, such as solvents or oxidation supporting media, are then injected into the enclosed area to convert the substance therein into flowable form. Finally, the substance as so converted is withdrawn from the enclosed area.

Abstract: A method of mining sulphur from an underground deposit overlying a soluble salt layer, wherein spaced parallel rows of repression boreholes and depression boreholes are drilled to penetrate into the salt layer, production boreholes are provided in a row intermediate the repression and depression boreholes, hot water or brine is introduced to the salt layer through the repression boreholes to create a superheated salt solution which is directed into the sulphur deposit, brine is pumped out through the depression boreholes thereby causing a flow of hot brine through the sulphur deposit from the repression to the depression boreholes which melts and entrains sulphur, and this molten sulphur is pumped up through the production boreholes. Hot water or brine is also introduced through the production boreholes to keep sulphur filters at the lower ends of the production boreholes clear.