The State of Alabama possesses extensive coal resources, and is a major coal producing state. Although these resources are impressive, there are many thin, deep coal seams which cannot be economically recovered by conventional means. The south-westward dip of the Warrior coal basin into Mississippi results in many coal seams which have a prohibitive amount of overburden for surface or underground mining using conventional technology. In addition, the coal is a swelling bituminous coal , which presents quite different problems in gasification from the lignite and sub-bituminous coals which have constituted the major research effort for in situ gasification in this country. This research was aimed at the development of technology for the underground gasification of these thin, deep seams of swelling bituminous coal.