METHOD OF COAL BOREHOLE MINING Russian patent published in 2001 - IPC

FIELD: mining industry. SUBSTANCE: method includes drilling of at least two boreholes, formation of underground gas generator by making connecting channel between boreholes, ignition of coal in channel and gasifying of coal mass with supply to underground gas generator of blast through one of boreholes, and withdrawal of formed gas through the other borehole. In the course of gasification, use is made of preferably alternating oxygen and steam blowing. Effluent gas is sharply cooled to temperature ensuring equilibrium between steam and products of its dissociation. In addition, effluent gas is cooled with liquefied nitrogen, carbon dioxide supplied to sealed annular space of gas-outlet borehole. Cooling agent is directly supplied to lower end of gas-outlet borehole. EFFECT: increased calorific power of produced gas. 4 cl, 1 dwg