Spontaneous combustion is one of the main sources of fires in underground coal mines. Most of these fires are initiated in the caved area (gob). This process starts with the formation of hot spots, which may develop into the self-heating of coal. A study involving experimental measurements and computational fluid dynamics (CFD) simulations was carried out to identify the location of these spots. Four CFD gob models of three different permeability zones were formulated and solved. Three utilized a bleeder ventilation system and the fourth a bleederless system. The simulation results showed that in a model ventilated by a bleeder system, the hot spot was located in the consolidated zone near the return side of the gob. Once the process was initiated, it propagated along the tailgate side as the gob progressed. The leakage flow through the gob played an important role in determining the size and location of the hot spot. In the model ventilated by a bleederless system, the hot spot was located by the face line. This was mainly caused by air leakage from the headgate. The study concludes with a set of ventilation schemes and recommendation to reduce the development of hot spots.
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