740.    DOWD, J. J., ELDER, J. L., CAPP, J. P., AND COHEN, P.  Experiment in Underground Gasification of Coal, Gorgas, Ala. Bureau of Mines Rept. of Investigations 4164, 1947, 62 pp.

     Using various methods of operation, it was determined that gases could be generated specifically for use in generating power or for synthesis purposes.  It is estimated that 236 tons of coal were burned completely and 164 tons coked during the combustion period.  5 types of blasting were used:  Gas-air, O₂-air, O₂-air-steam, O₂-steam, and steam.  Comparative heating values for each of those methods per cu. ft. of gas were, respectively:  47, 50, 110, 135, and 200 B.t.u.  It was also determined that the first 2 methods produced gases suitable for power generation, while the last 3 yielded gases suitable for synthesis purposes.