A range of technologies are available to recover methane from coal:
Coal Bed Methane (CBM)
Methane recovered from un-mined coal seams. The coal seams may be mined in the future but this is largely dependent upon geological factors, such as coal depth and quality.
Coal Mine Methane (CMM)
Methane recovered during mining activities as the coal is in the process of being extracted and thus emitting significant quantities of the gas.
Abandoned Mine Methane (AMM)
Methane recovered from mines that have been abandoned following the completion of mining operations. Significant amounts of methane may remain trapped in the mine or may continue to be emitted from openings.