Abstract: A method of extracting hydrocarbons in situ from an underground hydrocarbon deposit such as oil shale. A selected part of the deposit is heated by one or more electrical induction coils arranged in a quasi-toroidal configuration to temperatures high enough to drive off hydrocarbon fractions as gases or vapors, which are then collected and utilized in surface operations or recovered for transportation or temporary storage. The deposit may optionally be heated through a coking and cracking stage. Any remaining hydrocarbons may be burned in situ and the combustion gases utilized for energy. Steam may be obtained by injecting water into the heated shale after extraction of the hydrocarbons.

Abstract: The electric induction heating in situ of a selected portion of an underground deposit of hydrocarbons (such as petroleum, especially petroleum entrapped within a sand formation or the like, or lignite), for the purpose of facilitating extraction of hydrocarbons from the deposit. The heating is conveniently effected by passing alternating current through a conductor encompassing the selected portion. The conductive path is preferably a toroid, helix, or simulated toroid or helix, created by drilling and passing one or more conductors through the drill holes.

Abstract: A method of extracting metal from an underground ore body. The body is heated by electric induction to a temperature sufficient to break up the metallic ore compound and liquefy the metal. The metal flows into production wells where it is collected and transported to the surface, as by rapid solidification into powder or pellets in a pressurized gas stream. The electric induction is conveniently effected by passing alternating current through a conductor encompassing that portion of the ore body to be heated.

Abstract: A method of extracting hydrocarbons in situ from an underground hydrocarbon deposit (such as petroleum or lignite). A selected part of the deposit is heated by electrical induction to temperatures high enough to drive off hydrocarbon fractions as gases or vapors, which are then collected. The deposit may be heated through a coking and cracking stage. The electrical induction heating is conveniently effected by passing alternating current through a conductive path encompassing that part of the deposit to be heated.