"The in situ coal-gasification concept of the Lawrence Livermore Laboratory (ILL) has been technically and economically appraised on paper y an industrial team consisting of The Resource Sciences Corporation, Amoco Production Company, E.I. du Pont de Nemours & Co., Inc., Pacific Gas and Electric Company, and Rocky Mountain Energy Company. The evaluation included such considerations as coal-resource assessment: coal-permeability determinations; hydrologic factors; explosive-fracturing technology; drilling programs; site selection; underground reactor design; processing and control; potential water sources and treatment; environmental effects; aboveground processing, including utilities and offsites; and economics. The economic appraisal of conservative and optimistic cases indicates that pipeline-quality gas produced by in situ coal gasification could compete in price with synthetic natural gas produced by other technologies that are under consideration today. However, technological uncertainties in the areas of explosive fracturing, coal-extraction efficiency, and subsidence control must be eliminated via field testing for this concept to become a viable source of synthetic natural gas from coal."