A method for the underground gasification of coal or browncoal.

摘要

A method for the underground gasification of coal or browncoal, using two boreholes (1, 2) extending through a coal layer (3) with the slope of said layer, for supplying oxygen to a combustion and gasification front in said layer and discharging combustion gases respectively, a filler material being intermittently supplied through one of said boreholes for filling the cavity produced by burning away the coal layer. According to the invention, said filling is started at a moment before the combustion front has reached the discharge borehole, and in particular before the overlying formations will collapse to such a degree that an inadmissible subsidence at the ground level would develop. Thereafter the combustion and gasification is restarted in the same or the opposite sense as may be required for adjusting the orientation of the gasification front in the desired direction.