Coal Bed Methane
Coalbed methane is a gas that is extracted from layers of coal seams in the earth. It is usually extracted via drill holes but in the process large volumes of ground water are also brought to the surface. In the U.S., contaminated coalbed methane water is either being released into the environment or ponded in both Wyoming and Montana.
Read the full entry on Coal Bed Methane at SourceWatch, or find out more through these other resources.