"The principal objective of this research project is to develop and field test an induction system and estimator algorithm for remote determination (at the surface) of the location, shape and size of underground coal burns. In order of brevity only field measurements are reported on here. Field measurements were conducted with a wideband loop-loop induction system at the Hanna Underground Coal Gasification Site of the LERC during, July, August and October 1976. Soundings were made on five traverses at two different locations . Field data were processed on a Fourier Analyzer System and 3- dimensional response maps were plotted via the central computing system in both time and frequency domains. Strong anomalies at 5 kHz were observed on traverses over both burns at Hanna II. Induction soundings at 5 kHz (corresponding to a depth of penetration comparable to the coal burn depth) taken at Hanna II. Phase 1 indicate that the burn may have protruded 5m farther to the West than originally estimated by the LERC. Induction soundings at the Hanna II. Phase 2 and 3 show that the low frequency response acquired a second peak with aging . However, the high frequency response changed dramatically, probably due to removal of the horizontal pipes interconnecting the wells. These results would support the conclusion that there is a possibility of monitoring the burn front and delineation of the burn is not dependent on the cavity filling with saline ground water but invasion of the burn region by ground water may possibly be detected."