Underground Coal Gasification

Underground coal gasification is an industrial process that converts coal into gas while it remains in the ground, rather than mining it first and gasifying it at the surface. Oxidants and steam are injected into an unmined coal seam through wells, and the resulting product gas, chiefly methane, hydrogen, carbon monoxide and carbon dioxide, is drawn to the surface through separate wells. Because the coal itself is never extracted, the process can reach deposits that are too deep or otherwise uneconomical to mine conventionally. Testing began in the Soviet Union between 1928 and 1939, with the first successful trial in 1934 at Lysychansk, and further experiments followed after the Second World War in the United States, Europe and elsewhere. Operational underground coal gasification facilities have run in Uzbekistan and Russia, with pilot projects also carried out in Australia, South Africa and China. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/