Underground coal gasification (UCG) is a coal mining method applicable to coal seams at the depth from 300 to 2000 m where conventional coal mining is either economically ineffective or impossible. Two types of wells are drilled to enable gasification: an injection well and a production well. After completion of drilling works the underground seam is ignited and supplied with oxygen and water through the injection well.
2С + О2 -> 2СО + Q
С + Н2О -> Н2 + СО + Q
The produced syngas can be used for production of synthetic transport fuels or for regeneration of electric power.