Coal dust explosions using various concentrations of dust were performed and the gaseous and solid explosion products were analyzed. The explosion severity parameters P-m and (dP/dt)(m) were found to initially increase and then decrease with increasing dust concentration, while combustion time, t(c), exhibited the opposite trend. The value of t(c) was also found to exhibit a linear correlation with both P-m and (dP/dt)(m). Volatile matter and fixed carbon were the major components of each explosion and were significantly reduced in residues. CO, CO2 and CH4 were the major gas components and were present at different levels depending on the dust concentration. Micropores and mesopores played an important role in the explosion process. The data show that an explosion involving a low dust concentration is dominated by heterogeneous combustion, while homogeneous combustion is the primary process when employing worst-case and high concentrations.