The tectonic coal and its effects on coal and gas outburst

Both properties of higher porosity and lower permeability of the tectonic coal make it possible to keep more gas content and holding higher gas pressure. The isolating action and gas-cushion action of the free gas in tectonic coal cut down the resistance of coal-body against outburst. The specific property of high-deformed-extent of tectonic coal makes gas desorption, escape and flowing quickly become possible. The existing of weak-seam or thoroughfare-seam create suitable conditions for the initial erupting and continued developing of coal and gas outburst. On the whole, the existing of tectonic coal with certain thickness is the essential condition of coal and gas outburst, but not the sufficient condition.