RI 9206 - Model of Coal Dust Explosion Suppression by Rock Dust Entrainment

The Bureau of Mines developed a mathematical model to calculate the aerodynamically induced lifting of coal and rock dust from a composite deposition on a mine entry floor and the subsequent transport of the dust ahead of the propagating combustion zone of a coal dust explosion. For a series of experimental explosibility tests approximated by combustion zones that expand at a constant flame velocity, the mass fraction of airborne rock dust ahead of the flame front, as well as the mass fraction overtaken by the combustion zone, was calculated. A statistical analysis of the theoretical results demonstrated with a high level of confidence that the propagating and nonpropagating test samples belonged to sepa-rate populations. This analysis was further supported by an independent model of the average temperature over the combustion zone.