Methane Capture and Utilisation

The Australian coal mining industry contributes, approximately 6.5% of Australia's greenhouse gas production while producing 1.9% of GDP (1995/96). The coal mining industry's greenhouse intensity is high. Current estimates indicate that 72% of the greenhouse gas emissions attributed to the coal mining industry are in the form of fugitive emissions of methane from underground mining. Based on a 20-year impact, methane produces a 21 times greater heating effect per ton than carbon dioxide. Treating the methane emission represents the best opportunity for the coal mining industry to reduce emissions. In a carbon trading/tax environment, mitigation of methane could provide mines with significant benefit.

The utilisation of Coal Mine Methane (CMM) in Australia is hampered by geographic isolation of the mines and the nature of its supply. Namely, fluctuating flow rate and concentration, low concentration, relatively small quantity and lack of pipeline infrastructure. Utilisation is limited to readily transportable products or products usable on the minesite such as electricity and clean water. By burning the methane the effect is reduced 7 fold. In addition coal mine methane has environmental advantages as it has no ash, contains almost no sulphur and because there is no nitrogen in the combustible portion of the gas. Substitution of coal mine methane for coal in a number of applications results not only in a reduction in methane released to the environment but also in significant reduction in SO2, NOx, CO2 and particulate emissions. Co-firing coal mine methane with coal can produce additional NOx emissions by non-selective reduction to N2.