Prevention and suppression of coal dust explosion in underground coal mines: Role of rock dust type, particle size, proportion, concentration, and thermal properties

Abstract

Rock dust inertant is commonly used for prevention and suppression of coal dust explosion in underground coal mines. The effects of rock dust type, proportion, particle size, thermal conductivity, and specific heat capacity on minimum ignition temperature (MIT) of coal-rock dust mixtures and intensity of explosion propagation under different experimental conditions were examined using Godbert-Greenwald furnace integrated with a high-speed camera. MIT of coal-rock dust mixtures significantly increased with increase in rock dust proportion. With decrease in particle size from < 850 to < 75 µm, the mean MIT increased from 616 to 657 °C and 627 to 665 °C for dolomite and limestone dust, respectively. With increase in dust concentration from 500 to 3000 g/m3, the ignition temperature (IT) of coal-rock dust mixtures decreased by 28 % and 30 % for dolomite and limestone dust, respectively. Moreover, the MIT significantly increased with increase in thermal conductivity and specific heat capacity of coal-rock dust mixtures. Limestone dust proved to be a better explosion suppressant compared to dolomite dust.