Spontaneous combustion of certain Indian coals—some physico-chemical considerations

In the present work, an attempt has been made to evolve a method to identify coal's proneness to spontaneous combustion. Some suggestions have also been made to control such ignition. It has been shown that if pyrite is present in a coal in finely divided form, the proneness of coals towards spontaneous combustion increases; and the temperature of a coal bed increases if water is added to it, which tends to indicate that water spraying or even flooding cannot be considered as an effective measure to control spontaneous combustion. Moreover, it is also suggested that if a coal body is chilled (to − 193 °C) the micropores and microcracks in the coal are possibly contracted. Atmospheric oxygen is less likely to enter the coal through micropores and microcracks; and hence chances of spontaneous combustion due to auto-oxidation are diminished.