A modified in-situ retort for the retorting of oil shale is constructed by mining an open space having a volume of twenty-five to thirty-five percent of the volume of the retort in the bottom of the retort and thereafter blasting the oil shale that is to remain in the retort as rubble in a manner to...http://www.google.es/patents/US4378949?utm_source=gb-gplus-sharePatente US4378949 - Production of shale oil by in-situ retorting of oil shale
Production of shale oil by in-situ retorting of oil shale
