Spontaneous combustion studies of U.S. coals

Abstract

This report describes laboratory studies conducted by the Bureau of Mines on the spontaneous combustion of U.S. coals. Approximately 11 pct of U.S. underground coal mine fires are attributed to spontaneous combustion. The relative self-heating tendencies of 24 coal samples were evaluated in an adiabatic heating oven. An empirical expression was determined predicting a bituminous coal's minimum SHT in the adiabatic oven based on the coal's dry ash-free oxygen content. A new moderate-scale apparatus is described, in which the self-heating tendencies of larger coal samples, 3 kg, can be evaluated.