Methane gas hydrates influence on sudden coal and gas outbursts during underground mining of coal deposits

摘要

The mechanism of gas hydrates formation in coal seams is studied in the paper, as well as their involvement is hypothesized in the sudden outbursts of coal and gas during underground mining of coal deposits. It has been substantiated and proved that one of the real reasons for subsequent outbursts is the formation of gas hydrates in coal as a type of secondary gas hydrate deposits. It has been also substantiated that, as a result of coal metamorphism, a large amount of gaseous hydrocarbons, mainly methane, is formed in the seam, which under certain thermobaric conditions leads to the gas hydrates formation. It has been experimentally proved that the mechanism of such inclusions formation between gas hydrate and coal is a result of strong chemisorption, which, when disturbing thermobaric conditions, leads to gas-dynamic activity of coal seams. It has been revealed that during the dissociation of gas hydrates, obtained in a medium of activated coals, twice as much gaseous methane is released. The research analysis indicates that the formation of natural gas solid solutions in coal pores under certain thermodynamic conditions and the natural humidity, characteristic of coal seams, is one of the causes of sudden coal and gas outbursts. The gas hydrates dissociation influences on the gas-dynamic activity of a coal seam and the formation of an outburst hazardous situation.