Abstract: The present invention provides a method of in situ extraction of bitumen from an oil-sands body which method comprises sinking an access shaft through the oil-sands body, driving an access drift in the rock strata underlying the oil-sands body, delineating a rectangular block of oil-sands in said body by drilling and blasting the oil-sands body to provide substantially vertical planes of fractured oil-sands on all four sides of an enclosed mining room capable of retaining liquids and gases under pressure and comprising solid pillar walls, providing generally upwardly extending bores in said block of oil sands from the access drift in the said body, providing perforated pipes in those portions of the bores in said block, the perforations of said pipes being dimensioned to prevent sand particles from said block passing therethrough, increasing the permeability of the block of oil sands within said room by fracturing said block, flooding the mining room with a hot fluid at a temperature and for a residence time