SPONTANEOUS COMBUSTION SUSCEPTIBILITY OF U. S. COALS.

The chemical and thermal criteria used for predicting the spontaneous combustion hazard are reviewed and data are presented to characterize the gas desorptions and self-heating tendencies of 29 U. S. coals. CO, CO//2, and CH//4 are the main gases evolved and the CO, CO/ DELTA O//2 index, and O//2 absorption rate increase with decreasing rank and increasing oxygen content. The presence of CO alone is not necessarily an indication of a self-heating reaction of the coal.