Attempts have been made to classify various Indian coals with respect to their susceptibility to spontaneous combustion based on their crossing point temperature. Over fifty Indian coals were used during this investigation and it could be concluded that crossing point temperature can be gainfully used for this purpose. In general, higher crossing point temperature signifies lower susceptibility, whereas lower crossing point temperature indicates higher susceptibility to heating. Both the crossing point temperature as well as the slope of the time-temperature curve should be taken into consideration for determining the degree of susceptibility of coals to spontaneous combustion. Coals which show low crossing point temperature and a sudden sharp rise in the slope of the time-temperature curve may be considered to be highly vulnerable to spontaneous heating. It was also observed that higher rank coals are normally less susceptible to spontaneous combustion than lower rank coals
