Heat evolution when donbass coals react with the oxygen of the air

The activity with respect to the oxygen of the air and the heat effects of the oxidation reaction of coals of equal rank differ considerably. This is due to the difference in the genetic type with respect to the degree of reduction of the coals and their liability of self-ignition. The magnitude and nature of the distinctions in the metamorphism series are not the same. It was found that the evolution of heat when coals of the reduced and slightly reduced types having a tendency of self-ignition react with oxygen is 1.5-5.0 times higher than for coals not inclined to self-ignition, and is maximum for low-rank coals and coals with a carbon content of about 90%.