The Laramie Energy Research Center of the U.S. Bureau of Mines conducted an in situ coal gasification experiment at Hanna, Wyoming, during 1973-74. Sandia Laboratories participated in the latter phase of the experiment by performing feasibility studies of different instrumentation and measurement techniques. These studies, which included surface resistivity scans, seismic/acoustic measurements, and temperature measurements, demonstrated that signals and effects associated with the in situ combustion process could be detected.