Abstract: This invention relates to novel leaching methods and apparatus for recovering minerals such as ores, high viscosity oil, and the like, from the subsurface earth formation. More specifically, the formation is penetrated by a plurality of mine shafts or large-diameter boreholes which are spaced apart as a function of the lithological characteristics of the formation. Thereafter, a suitable leaching fluid such as a liquid solvent, steam, free hydrogen, or carbon dioxide is injected into the formation through a plurality of drill holes radially extending from the lower portions of the shafts.In a particular technique for recovering high viscosity oil, the formation is initially subjected to a sequence of "soaking" cycles, wherein fluid is injected into the formation during separate discrete time periods, and wherein dissolved minerals or reduced viscosity oil is drained from the drill holes during the interval following each injection period.