METHOD FOR UNDERGROUND GASIFICATION OF FOSSIL FUEL

A method for underground gasification of fossil fuel comprises preparing a gas generator by drilling in the seam of fossil fuel borehole passages and vertical boreholes including main boreholes located at the beginning of the passage and intermediate boreholes arranged along the longitudinal axis of each borehole passage on either side of the axis and alternately, each next borehole being located on the side opposite to that on which the preceding borehole is located; providing a fire face on the borehole passage end side; fire-working the borehole preceding beginning from the fire face; alternately crosscutting the vertical boreholes with the borehole passage beginning on the fire face side; gasifying fossil fuel within individual portions beginning from the fire face side by alternately blasting through each intermediate borehole directionally in the seam plane at an angle to the longitudinal axis of the borehole passage and in the direction away from the longitudinal axis of the borehole passage for a time required for gasifying maximum 20% of fossil fuel deposit within each portion of the borehole passage and to ensure a thermal preparation of the seam, the blasting being effected by increasing its intensity in each intermediate borehole proportionally with an increase in the length of the borehole passage; removing the resultant gas within each portion in the direction toward the fire face; subsequent gasification of fossil fuel by blasting through the main boreholes or both through the main boreholes and boreholes passages, and removing the resultant gas.