Methane is often vented to the atmosphere in the degassing of coal mines. Technologies to economically recover methane for fuel use, which could reduce emissions by 30-90% (IPCC-TP-1, 1996), have been developed and are commercially available. Pre-mining degasification or enhanced recovery using vertical or horizontal in-mine boreholes can economically recover methane produced via drainage (which represents 30% of all coal mine methane). Nevertheless, the major fraction (70%) is produced via the ventilation systems and being very dilute (< 1% in air) is presently vented (US EPA, 1993). Technology should focus on the utilisation of this dilute stream. Estimate for equivalent CO2 emission reduction by recovering and utilising CH4 from one mine reaches 1 TgC/year. Capturing all CH4 from coal mine and burning is estimated to have the potential to reduce greenhouse gases by about 5% of the CO2 emitted from coal burning (APEC, 1997).
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