The Bureau of Mines used portable infrared scanners to examine the surface of pillars and faces in the Somerset Mine near Somerset, Colorado. Zones of temperature buildup, indicative of potential combustion, were detected with the scanners; their existence was verified by temperature measurements with conventional instrumentation. Temperatures of 32 deg. to 62 deg. C were measured on surfaces with normal temperatures of 26 deg. to 35 deg. C. The infrared instruments and techniques appeared to offer a rapid and efficient method for locating potential trouble spots in mines susceptible to fires caused by spontaneous combustion.