The characteristic of explosion under mine gas and spontaneous combustion coupling

The gas explosions often occur under mine gas and spontaneous combustion coupling in coal mines. The coupling of mine gas and spontaneous combustion is a complex disaster, and the character of the disaster is not clear now. The paper primarily discussed the character of gas explosion under mine gas and spontaneous combustion coupling. The explosion concentration range of mixed gases including CH4 and CO is studied. And the potential area and the course of explosion detonated by spontaneous combustion of coal is analyzed. When the spontaneous combustion of coal occurs, it can produce plenty of CO and fire-heating air pressure in the goaf. Experiments show that the upper limit of explosion concentration rises rapidly and the lower limit rises slowly with the increase of CO in the mixed gas of CH4 and CO. The fire-heating air pressure results in continuous mix of the gases and heat convection under vortex action between the combustion zone and non-firing zone. Thus, gas explosion occurs. In order to prevent high-concentration gas in the goaf and spontaneous combustion which detonates gas explosion in the coal mine, three-phase foam with nitrogen is adopted to restrain gas explosion and reduce coal temperature.