Underground coal gasification and extraction involves the partial burning of coal underground to produce a mixture of gases.
Underground Coal Gasification (UCG) involves the gasification of the coal in-situ by drilling boreholes into the seam, injecting water/oxygen mixtures down one pipe, igniting and partially combusting the coal and extracting the gasification products (known as syngas) through the other pipe.
It produces a mixture of gases, (mostly carbon monoxide, carbon dioxide, hydrogen and methane) that can be processed to provide fuels for power generation, vehicle fuels and chemical feed-stocks.
The UK has significant coal reserves that are believed to be suitable for UCG and cannot be accessed using conventional techniques such as deep shaft or open cast mining.
The government supports the development of UCG and the Coal Authority started issuing exploration licences in 2009. UCG is also being developed in other countries, notably Australia and the USA.
Click here to read about the potential impacts of underground coal gasification.