Fugitive greenhouse gas emissions in ventilation air from Australian underground coal mines

Seam gas released during coal mining is a substantial source of fugitive greenhouse gas emissions worldwide. Most of these emissions originate from underground mining; however, lack of robust global data means that the scale of emissions remains uncertain. Some coal-producing countries are attempting to improve the quality of emission estimates by using ventilation data to calculate emissions from individual mines. Legislation recently introduced in Australia now requires coal mine operators to estimate and report annual fugitive emissions. This article examines the methodology currently used at most Australian mines to meet these requirements. To assess the performance of this methodology, we compared the results of routine measurements of ventilation air flow rate and gas composition to those made with reference methods. The primary sources of uncertainty in the techniques are identified and their contributions to the uncertainty of the reported fugitive emission fluxes are estimated.