Two major field recovery experiments have been conducted by the Laramie Energy Research Center in the Rock Springs, Wyoming, area. The first of these was based on fracturing with desensitized nitroglycerin and proved to be quite successful in that approzimately 200 barrels of oil were produced. The recovery from this first experiment was very low because the 200 barrels of oil represented less than 2 percent of the resource in place. Material and energy balance calculations indicated that some 25 to 30 percent of the oil in place had been retorted but was not obtained aboveground. In an attempt to improve recovery a larger experiment was designed. The fracturing was accomplished by detonating pelletized explosive in wellbores. This experiment was not successful. Combustion on this site was sustained for several months. Oxygen utilization at times was very good, carbon dioxide production was high, but no liquid oil was obtained aboveground. It was decided that insufficient permeability had been created to sustain the high reaction rates required for production of oil from the formation.