The decomposition of methane hydrates in coal seams can be one of the causes of the origination of sudden emissions of coal and gas (coal outburst). The formation possibility of methane hydrate in the inner space of natural coal of several types was experimentally studied in the work. Experimental P–T diagrams for a closed system containing wet coal and free methane, demonstrate the peak methane emission into the gas phase when intersecting the curve of the equilibrium of gas hydrates. Less than half of water, sorbed by coal is involved in the formation of gas hydrates. It was shown for the first time that with the degree decrease of metamorphism of coal, the amount of water that is absorbed by natural coal is increased, however herewith; a proportion of water involved in the formation of methane hydrate is decreased