Instrumentation for Measuring Fugitive Emissions in Ventilation Air from Underground Coal Mines

Fugitive emissions are the largest source of greenhouse gas emissions from the Australian coal industry, most of which are associated with the ventilation air from underground mining. Under the requirements of the National Greenhouse and Energy Reporting Act, Australian coal mines must report annual greenhouse gas emissions, including fugitive emissions, according to specific methods in the Determination issued with the Act. The procedures specified in the Determination for estimating fugitives are based on internationally recognised standard methods, which are substantially different from the methods currently used for estimating fugitive emissions. Recent  projects C18005 and C18048 have shown that the procedures proposed in the Determination are not generally suitable for use in the underground coal industry. Furthermore, it was found that methods currently used by mines to measure ventilation air flow and composition for fugitive emissions reporting may be subject to significant errors thus yielding emission estimates with high uncertainties.

Some mine operators are considering installing continuous emissions monitoring systems for measuring fugitive emissions because these systems potentially yield the most accurate results. However, despite the apparent advantages of continuous monitoring for measuring fugitive emissions, the instrumentation must be suited to mine use. Moreover, it may be difficult to calibrate continuous flow measuring systems according to the requirements of some standards relating to such systems.

In this project the requirements of instrumentation suitable for continuous monitoring of fugitive emissions was were examined and a review of relevant stands was undertaken. In addition further examination of the use of anemometers for measuring ventilation air flows for fugitive emission estimation was examined specifically to assess the accuracy of the method and define the uncertainties for greenhouse reporting. A robust anemometer method may also be of value in checking the performance of continuous flow sensors; especially where full Pitot tube traverses of surface duct work is difficult or impractical.