Exploration for the recovery of oil shale in Morocco started at Tangier with the creation of the Société des Schistes Bitumineux de Tanger. The company built a pilot plant with a production capacity of 80 tons per day of oil shale between 1939 and 1945. The Timahdit and Tarfaya deposits were discovered late in the sixties.

Following the oil crisis of 1973 and 1979, research and development into the recovery of oil shale increased significantly throughout the world. In Morocco both the Tarfaya and Timahdit deposits have been the subject of several geological and mining studies, laboratory studies, and tests of pyrolysis and direct combustion. The oil shale from these deposits has been tested by several pyrolysis processes around the world: in the United States (Tosco, PARAHO and Union Oil); in Europe (LURGI); in the former USSR (KIVITER and GALOTER); in Canada (TACIUK); and in Japan (JOSECO). They have also been the subject of many techno-economical feasibility studies.

Geological, mining, and laboratory studies, made between 1975 and 1985, allowed the identification of reserves in place and the characterization of oil shale in Timahdit and Tarfaya, and showed that Moroccan shale could produce hydrocarbons by pyrolysis. Morocco then initiated the T3 plant, with initial development of three deposits of Tangier, Tarfaya and Timahdit.