While the oil and gas industry and the waste sector are two of the biggest sources of methane pollution, reductions in other sectors are not only economically justified but critical to realize the full climate benefits of methane mitigation. Methane emissions also come from coal mining operations. CATF is working to develop innovative solutions, financial mechanisms, and policies that can be applied both in the U.S. as well as internationally to minimize their climate impacts.
Coal Mine Methane
Coal mining is responsible for roughly 12% of global anthropogenic methane emissions. Methane in coal seams – deposits of coal that are visible within layers of rock – is created as part of the same geological process that leads to the formation of coal. Large quantities of methane are typically trapped in or near coal deposits and are released during mining operations. Methane is emitted from a number of sources and operations, including:
- Degasification systems and ventilation air from underground mines;
- Abandoned or closed mines;
- Surface or open pit mines; and
- Fugitive emissions from post-mining operations, such as coal transport and storage.
Underground mines are the single largest source of coal mine methane emissions. Due to its threat to miner safety along with its high explosion risk, methane is removed with large-scale ventilation systems that move massive quantities of air through the mines. As a result, large amounts of very low-concentration ventilation air methane – usually containing 0.1 to 1% methane – is released into the atmosphere. Ventilation air methane emissions are responsible for nearly 70% of all underground fugitive methane emissions. Gas drained from a coal seam prior to mining can contain methane concentrations ranging from 60 to 90% methane, while draining methane from post-mining operations (gobs) can contain concentrations of 30 to 95% methane.
While financial, institutional, and even technological barriers to capturing and utilizing coal mine methane do exist, utilization of high-concentration methane as well as upgrading it to pipeline quality gas for sale, are both common practices. Technologies also exist to capture and use low-concentration ventilation air methane, however, additional research and technological advances are necessary for wide-scale implementation.
The development of robust policies and regulations are critical to reducing greenhouse gas emissions associated with the mining sector. CATF is working in conjunction with multiple organizations, institutions, and the private sector to turn these barriers into opportunities for action.
