Spontaneous combustion susceptibility of U.S. coals.
Kuchta-JM; Rowe-VR; Burgess-DS
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8474, 1980 Jan; :1-34
The chemical and thermal criteria used for predicting the spontaneous combustion hazard are briefly reviewed and data are presented to characterize the gas desorptions and self-heating tendendies of 29 U.S. coals. Closed vessel desorption experiments showed that CO, CO2, and CH4 are the main gases evolved and that the CO, CO/deltaO2 index, and O2 absorption rate increase with decreasing rank and increasing oxygen content of the coal. The effects of temperature, moisture, and other variables are discussed together with the application of the data to the complex conditions encountered in a mining environment. The presence of CO alone in a mine is not necessarily an indication of a self-heating reaction of the coal. Based upon experiments conducted in an adiabatic-type calorimeter, the self-heating temperatures of lignite and subbituminous coals can be as low as 30 deg. C, whereas the bituminous coals require a temperature of about 60 deg. C or more. The self-heating hazard is greatest when the coals are dried and exposed to a high humidity condition, apparently as a result of the "heat-of-wetting." Generally, the hazard is greatest with the western coals of the United States.
Mining-industry; Underground-mining; Coal-mining; Combustibility; Spontaneous-combustion
IH; Report of Investigations
NTIS Accession No.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8474