Gorbachev Kuzbass State Technical University, Kemerovo, Russia:

V. G. Smirnov, Associate Professor, Candidate of Physico-Mathematical Sciences, smirnovvg@kuzstu.ru
V. V. Dyrdin, Professor, Doctor of Engineering Sciences

Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia:

V. N. Oparin, Professor, Doctor of Physico-mathematical Sciences, Corresponding Member of the Russian Academy of Sciences

Coal and gas outbursts are the hazardous gas-dynamic phenomena in underground mining of damaged coal seams of high gas content. Continuous monitoring of coal strength, gas pressure and gas content of a coal seam during mining fails to provide reliable prediction of outbursts. Given the current rates, commercial development of coal fields gradually involves deeper level seams with high content of coal gas. Mining of coal below a critical depth, which is usually 150–250 m, is associated with risk of coal and gas outbursts, which greatly complicates mine operation, endangers life of mine personnel and makes it impossible to extract coal from seams in difficult ground conditions. The volume of gas released in outbursts is many times larger than the volume of natural gas content of coal seams. Coal and gas outbursts take places in weak and folded coal bands featuring high rate of gas recovery and increased thickness in the zones of faulting. The hypothesis about a solid coal–gas solution considers a coal and gas outburst as a phase transition with decomposition of the solid coal–gas solution. This article shows that in the inner structure of fossil coal, some absorbed water can crystallize to a hydrate, and decomposition of the hydrate takes place nearby the equilibrium curve. The quantity of gas releasing in decomposition of hydrates is comparable with the quantity of absorbed and free gas in a coal seam. The gas released in decomposition of hydrates can be one of the factors of coal and gas outbursts.

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