Abstract Coal dust explosion constitutes an ever-present hazard in underground coal mines worldwide. This study examines the effects of important parameters, such as, dust particle size, dust concentration and dust-dispersion-air pressure on rock dust inertant requirement for suppressing coal dust explosion using a Godbert-Greenwald (GG) furnace. It also elucidates the underlying mechanism involved in the coal dust explosion and its propagation. The study revealed that the proportion of rock dust required to inert the coal dust explosion increases with the decrease in the coal dust size and increase in the rock dust size. The finest size coal dust (