Australia’s coal mining emissions paradox

The biggest driver of fugitive emissions reductions has been underground mine closures, but new expansions threaten to reverse these gains.

Outside the shift towards surface coal mining, the biggest driver of actual emissions reductions in the coal sector has been the recent decline in underground mine production and the closure of a sample of high emitting, gassy coal mines. This highlights the opportunity of strategic coal mining closures of super-emitting underground mines as a short-term opportunity for significant emissions abatement.

In 1990, total underground coal mine production for that year was estimated at 61 million tonnes. Since then, total underground coal production has grown significantly, with a peak of 125 million tonnes of underground coal production in 2015. Since this peak, annual underground coal production has been in decline each year, driven especially by coal mine closures and production impacts such as COVID-19 restrictions and floods in years since; but production was still 46% higher in 2022 compared to 1990.

Underground mining plays a particularly significant role in Australia’s coal mine methane emissions. This is largely due to the nature of underground mining itself. As mining operations go deeper, particularly when extracting higher-grade metallurgical coals, substantial amounts of methane trapped in the coal seam are released.

As a result of mine design, underground mines release the majority of their methane through the mine’s ventilation shaft. This is a source that can be significantly reduced through strategic investments in methane capture technology, both prior to, and during mining.

While underground mining now makes up approximately 15% of all coal production in Australia, it makes up approximately two-thirds of total fugitive emissions from coal mines. Of this, a small handful of highly gassy mines make up the lion’s share of emissions.

In Queensland for example, of all large emitters reporting to the Safeguard Mechanism, only four large underground mines contribute up to one third of all estimated scope 1 emissions in the coal sector. In 2023, only 12 underground and mixed mines reported 65% of the state’s reported scope 1 emissions under the Safeguard Mechanism. While these reflect overall scope 1 emissions rather than fugitives alone, for many underground mines, more than 90 per cent of their scope 1 emissions share comes from “fugitive” methane alone.

Similarly in NSW, only three large underground mines contributed more than one third of all coal mine emissions reported to the Safeguard Mechanism in 2023. More than half of all scope 1 emissions reported that year came from only 6 underground mines that contributed only 14% of overall coal production in the state. Considering that there are fewer Safeguard reporting coal mines in NSW than in QLD, and a number of the state’s open-cut mines have reported extremely low emissions after shifting their emissions reporting to site-specific fugitive measurement, we expect that an even greater proportion of the state’s reported fugitive emissions are contained within a small number of underground mines.

As a result, a handful of super-emitting coal mines can have a significant impact on the state and country’s coal mining emissions. If one of these super-emitting mines closes, or production in those mines decreases, that would result in a significant reduction of overall coal pollution. Similarly if strategic investments are made to reduce their emissions while not impeding on production levels, fugitive emissions at many of these super-emitting mines could be decreased by between 70-80%.

In the case of Australia’s most recent underground fugitive emissions decrease, there have been strategic mitigation investments. Anglo American, which previously owned super-emitting metallurgical mines such as Moranbah North, Grosvenor, Aquila and Grasstree, invested in “excess of USD $100 million per annum, in methane capture infrastructure” in pre-mine drainage over the last few years. As a result, it reported capturing and mitigating up to 60% of its potential methane emissions last year, compared to a baseline of 2019.

However, the large majority of emissions reductions have come as a result of unintentional emissions decreases as a result of the closure of older, super-emitting coal mines. This includes the closures of Coalcliff mine in 1992, underground mining at Muswellbrook and Collinsville in 1997, Dartbrook in 2007, Mannering Colliery in 2013, West Wallsend Colliery, which closed after 47 years of operation in 2016, and Austar coal mine, which closed after 100 years of mining in 2020.

It also includes the partial closure of many super-emitting mines due to methane-related incidents and explosions. In 2017, Appin coal mine, the highest emitting coal mine in the country, was partially closed and production significantly reduced for two years due to unsafe gas levels. In 2018, North Goonyella coal mine closed after a fire following months of rising methane levels. That was followed by Grosvenor coal mine which experienced a major methane-related fire in 2020, following 27 recorded methane exceedances in the year prior. The mine was re-opened only to experience a massive explosion last year. A similar history of coal mine methane-related incidents led to the closure of Russell Vale coal mine last year.

While investments in emissions abatement have partially contributed to the downward trend in fugitive emissions reporting across Australia’s underground mines, it is clear that the closure of super-emitting coal mines has had a far more significant impact on overall emissions trends. This not only reinforces the value of strategic closures of super-emitting underground mines as a short-term opportunity for significant emissions abatement, but the critical pollution risk of extending and expanding these mines.

Future Risks and expansion concerns

Going forward, the CSIRO has estimated that an additional 44 coal mines are scheduled to close by 2040. This should include super-emitters such as Aquila (2029) resulting in ongoing emissions reductions. These are already built into Australia’s forward emissions estimates, which assume that “from 2029 emissions are projected to decline due to reduced demand for Australian thermal coal, increased on-site abatement activities induced by the Safeguard Mechanism, and the closure of several large, gassy underground mines.”

However, research from civil society groups such as Lock the Gate and The Australia Institute highlight that there are currently 27 proposed coal mining projects that have not yet been incorporated into forward emissions estimates and could have a significant impact on forward emissions estimates.

In September last year, Narrabri underground coal mine was granted an extension to its operations licence from 2030 to 2044. Then in December, Lake Vermont Meadowbrook project was granted an expansion request to develop a new underground coal mine, which could transition the mine to becoming the third highest emitting coal mine in the country by 2028 if its fugitive emissions are not proactively mitigated. Finally Tahmoor coal mine is currently seeking approval to modify its current underground mining approach, potentially increasing its annual emissions increase by 57% in the next year alone if granted.

This concern is supported by the NSW Net Zero Commission, who notes that while NSW is about half way towards achieving the state’s legislated 2030 emissions reduction targets, it was specifically concerned about the “risks to the state’s targets from increased emissions in the resources sector.” A similar concern was raised at the national level by the Climate Change Authority, who noted that new coal and gas projects were undermining the viability of Australia’s climate targets.