Abstract: This invention relates to the extraction of oil shales and tar sands by using a solvent under supercritical conditions at a temperature within 200.degree. C. or its critical temperature in order to effect extraction of kerogen from the sand or shale.In the case of shales considerable heat needs to be applied to the shale before effective extraction can occur and extraction in this case may be carried out at a temperature within the range of 370.degree. to 450.degree. C.

Abstract: Process for the gas extraction of soluble constituents of coal which comprises heating the coal in the presence of an extractor to a terminal temperature of 400.degree.C. to 550.degree.C. where the extractant at the terminal temperature is in the gas phase to extract the soluble constituents from the coal and separating the extractant from the residue and recovering the extract from the extractant. The heating of the coal in the presence of an extractant is at an initial rate of 20.degree.C. per minute and preferably as fast as possible to an initial temperature of 370.degree.C. to 390.degree.C. preferably 380.degree.C. and thereafter heating the coal to a terminal temperature at a rate not more than 20.degree.C. per minute and preferably below 5.degree.C. per minute thereby minimizing secondary repolymerization reactions.