Commercial development of underground coal gasification

Underground coal gasification (UCG) is a process by which coal seams at depths uneconomic for open pit mining can be converted, using drillhole access, to a gas suitable for use as a fuel for power generation or as a chemical feedstock. Its application draws on a wide range of engineering and related disciplines including chemistry, geology, geohydrology, geotechnical engineering (including drilling techniques) and chemical engineering. This paper describes the UCG process and traces its historical development with particular reference to the vast amount of work undertaken in the former Soviet Union since the 1930s. Reference is also made to the most recent UCG tests in Australia (1999–2002), Spain (1997) and the USA (1987–1988), and to the new generation of projects that are in various stages of planning and development. The significance of the required specialist technical disciplines is discussed, and both environmental and commercial issues of specific relevance to UCG project developmen,t are reviewed.