METHOD OF ECOLOGICALLY SAFE UNDERGROUND GASIFICATION OF DEEP-SEATED COAL Russian patent published in 2009 - IPC E21B43/295 

FIELD: mining.

SUBSTANCE: invention refers to mining, particularly to underground gasification of coal on site of its natural deep-seated location. The method of underground gasification of coal consists in preparing an underground gas-generator to operation and in performing gasification of coal. Also the process of gasification is carried out with control over pressure in the underground gas-generator and with correction of hydraulic modes of blow and gas-withdrawing boreholes. Hydro-static level of underground water and concentration of chemical impurities in underground water is controlled by means of hydro-controlling and drainage boreholes. Drainage and vertical boreholes are assembled as water removing boreholes before commencement of gasification; operation of the said boreholes reduces hydro-static level of underground water. Withdrawal of gasification products is initially performed via a vertical borehole, further it is performed via gas withdrawing boreholes. Underground water withdrawn via boreholes is cleaned from impurities in a surface complex. Purifying of underground water in worked out space of the underground gas-generator is performed by means of biological method of de-composition and neutralisation of impurities.

EFFECT: prevention of ecological pollution of underground water with products of thermal decomposition of coal due to minimisation of gasification products migration from underground gas generator.

8 cl, 2 dwg