Abstract: A method and apparatus for the recovery of bitumen oils from oil shale. The method comprises crushing the oil shale to a predetermined particle size and mixing with an organic solvent to form a slurry. The slurry is then subjected to supercritical temperatures and pressures whereby the kerogen materials break down into bitumen oils which solubilize in the solvent. The liquid and solids are separated and the solid components are further treated under supercritical temperatures and pressures to yield further bitumen oils. The extracted bitumen oils are separated from solvent by fractionation, and upgraded by removing an asphaltenes residue. Off-gases and asphaltenes residue from the system are burned in a limestone fluidized bed combustor, which results in environmentally acceptable emissions and supplies process heat and power. The apparatus includes a high pressure autoclave-type vessel with an internal venturi draft tube, and a plurality of high pressure decantation vessels with internal lamellae thickeners.