Abstract: Disclosed is a method for mining minerals at depths where strip and deep mining methods are not practical or economical. After site layout, a plurality of generally parallel-spaced, elongated trenches are formed to expose the mineral bed. Continuous mining equipment is used to mine the minerals from the base of the trench. A conveyor is disposed in each trench to convey the mined minerals to one end of the site to a collection conveyor. After the minerals are mined from the base of the trench, mining tunnels are formed to the opposite sides of and generally perpendicular to each trench and adjacent one end thereof. The tunnels are extended distances at least several times the width of the trench and thereby form longwall mining surfaces. Longwall mining equipment is disposed in each tunnel and the minerals are mined by advancing the longwall mining equipment in a direction parallel to the trench and toward its opposite end. As the longwall mining equipment advances, the overburden caves behind the equipment.

Abstract: An electrical generating plant comprising a generator which is driven, during on-load periods, by a gas turbine; the gas turbine operates continuously and is powered by a continuous supply of fuel gas from a suitable fuel source and compressed air from an air storage reservoir; the reservoir is recharged periodically from an air compressor driven by the gas turbine during off-load periods only. The air storage reservoir thus serves to store energy supplied by the system during off-load periods and to return that energy to the system during on-load periods, in which the air compressor is inoperative and places no load on the gas turbine.