A series of experiments were conducted to obtain the characteristic sensor responses of commercially available gas, smoke, and flame sensors to fires of common combustible mine materials. The experiments were conducted in a large-scale fire gallery located at the National Institute for Occupational Safety and Health (NIOSH) Lake Lynn Laboratory (LLL) in Fairchance, PA, using Ponderosa Pine, Red Oak, Douglas fir, high and low volatile coals, PVC and SBR conveyor belt, No. 2 diesel fuel, and diesel exhaust. The sensors included a diffusion-type carbon monoxide (CO) sensor, photoelectric- and ionization-type smoke sensors, a video smoke/flame detector, and an optical flame detector. Simultaneous measurements were obtained for average gas concentrations, smoke mass concentrations, and smoke optical densities in order to quantify the levels of combustion products at the alert and alarm times of the sensors. Because required sensor alarm levels are 10 ppm and 0.044 m-1 optical density for CO and smoke sensors, respectively, the different sensor alarm times are compared to the times at which the CO and smoke reach these alarm levels. In addition, the potential impacts of using smoke sensors that have met the performance standards from accredited testing laboratories are also evaluated and discussed using the response data of an Underwriters' Laboratory (UL)-listed combination photoelectric/ionization smoke detector. These test results are further discussed relative to fire sensor needs and improvements that can have a positive impact on mine fire safety.