Reducing coal mine GHG emissions through effective gas drainage and utilisation
Gas emission from Australian coal mining is estimated to account for 4-5% of the nation’s 559 million tonnes of CO2 equivalent (MtCO2-e) Greenhouse Gas (GHG) emissions. With the intense focus on global GHG management and reduction, to slow the rate of climate change, significant community and political pressure exists to reduce the rate of gas emission. In December 2007 Australia committed to join the Kyoto Protocol, which in part requires annual GHG emissions not to exceed 108% of 1990 levels by the end of the 2012 commitment period. The current Australian Federal Government is presently developing the Australian carbon pollution reduction scheme, which is due to be implemented by 2010. This scheme is expected to place a value on GHG emissions and thereby introduce a financial penalty/incentive on organisations to manage and reduce their GHG footprint. In the case of the Australian coal industry, with an estimated annual GHG contribution of 22.5 Mt CO2-e, the introduction of the emissions reduction scheme will add in the order of half a billion dollars to the cost of operations (based on a carbon unit cost of $20/t CO2-e). In light of such a significant additional cost it can be expected that gas capture and emissions reduction will receive an unprecedented increase in attention and corporate support. This paper discusses the various sources of gas emission from underground coal mines and describes methods to improve both the capture and utilisation of this gas to reduce GHG emissions.