The processes of coal self-heating, which, as a rule, have a local character, are the most acute problems for the coal industry. Experimental and theoretical studies show that self-heating is influenced by the processes of heat accumulation and temperature increase, which means that more heat is formed in the area of rock and coal concentration than released into the surrounding environment. Thus, self-heating can quickly and unexpectedly go into fire, and then into an endogenous fire. Any source of self-heating is a thermal “source”, which is the cause for spreading thermal field that inevitably leads to an increase in the temperature of the rocks surrounding the faces and then the air atmosphere of the faces. A mixed boundary-value problem for a one-dimensional parabolic equation describing the temperature field in the areas of rock and coal concentration in the presence of self-heating zone was formulated in order to reveal the regularities of temperature field propagation in the vicinity of the self-heating zone. A formula is obtained that determines the temperature of the rocky-coal cluster. Calculations were performed on the basis of which the temperature dependences of the temperature in the rocky clusters were plotted against its thermophysical parameters and certain regularities of the temperature field in the cluster were revealed.