Thermal imaging method was used to inspect a two-stage gear system from a power transmission system of a belt conveyor located in an underground mine. Performing repairs in favorable time or preparing for failures contributes to the shortening of standstill periods and therefore to the minimizing of financial losses caused by purchasing replacement parts and unintended emergency stops. Processing of thermograms was done with the use of ThermoVision Processing software, which was designed at Machinery Systems Division, Wroclaw University of Technology, in particular for thermal imaging diagnostics of gear systems. The software automatically identifies gear-wheels and divides the gear system into predefined areas – Ar01 to Ar10. It allows for processing single files and whole folders. The inspection allowed to create object characteristics and specify its temperatures during steady work, which will serve as point of reference when the inspection is repeated at intervals of approximately several months. As a result, significant changes of the gear’s condition will become detectable, by calculating the difference between average temperatures for each area at two measurements. Temperature measurements are possible not only on the gear system but also on the motor shaft and the drive drum shaft. In the future, creating an application that would enable processing images of those parts will allow for multidimensional analysis of belt conveyor power transmission systems.