A method is described by which deeply buried coals can be converted to methane through chemical reactions with oxygen and water. The coal would first be shattered with conventional explosives, then retorted with an oxygen--water mixture at between 700 and 1300 K. The reactants would be pumped into the top of the coal deposit at between 500 and 1000 psi and carbon dioxide and methane would be removed from the bottom. No sulfur gases of fly ash should be produced and the water requirements can be fulfilled from brackish water supplies. Coals available and suitable for this kind of gasification might yield as much as 10,000 trillion ft 3 of pipeline gas. This constitutes about 300 times the present annual consumption, and if the process is successfully developed, it could materially alleviate future gas shortages. Rough estimates of process costs based on plant capacity of 0.1 trillion ft3 per year indicate that an investor could expect about 15% internal rate of return on a 42 million capital outlay assuming 38 cents per MVF of gas as a field price. Both the capital requirements and selling priced are much less than for surface gasification plants. Previous underground gasification has been accomplished with mined gallery or drill hole low pressure burning. The methods proposed here should minimize bypassing of the coal by the inlet gases and thereby maintain a high quality product. This is accomplished by flowing the reactant gases very slowly downward through the shattered coal, keeping the hot zones above the colder ones. This creates a thermally stable advancing hot zone and avoids the mixing of reactants and products. The proposed process will lead to ultimate surface subsidence of many tens of feet over the whole area of racted coal. Experience from potash mines suggests that there would be no surface disruption. While the concept appears most promising from a theoretical point of view, it is unproven. To test its feasibility it will be necessary to conduct a number of laboratory studies and calculations and to perform pilot scale field tests in suitable deep coal deposits.