Glencore's Ravensworth underground coal mine in NSW, which was mothballed seven years ago, has quietly leaked methane equivalent to more than a million tonnes of carbon dioxide (CO2), an investigation by the Australian Conservation Foundation has revealed.
That means the abandoned Ravensworth coal pit, which has not produced a lump of coal since 2014, still emits as much climate pollution every year as 33,000 cars on the road.
When Glencore asked for permission to expand the Ravensworth mine in 2010, the NSW government granted approval on condition the company found a way to capture and reuse the methane leaching out of the coal seam.
When the company failed to find a way to capture the methane, the government watered down the condition to allow Glencore to instead flare the methane - burn it before releasing it directly into the air - which converts it to less potent (but still heat-trapping) CO2.
Documents obtained by ACF reveal Glencore shut down the flares some time before 2018.
The information is revealed in a new report by ACF, Methane: Creating a stink for Australia and the climate crisis, which examines Australia's methane problem.
"Methane from coal, oil and gas extraction, production and distribution are Australia's fifth largest source of climate pollution, responsible for around 10% of our total emissions," said ACF's climate change campaigner Suzanne Harter.
"The growth in Australia's gas exports has seen a growth in fugitive methane emissions.
"Coal mining, domestic gas and oil extraction are ongoing sources of methane, while abandoned unproductive gas wells and coal mines - like Glencore's Ravensworth coal mine near Singleton in the Hunter Valley - keep releasing the dangerous climate pollutant.
"The Ravensworth example is part of a bigger problem of mining companies leaving zombie mines that continue to pollute the environment long after the mining has stopped. Australia-wide, fewer than 30 mines have ever been fully closed, rehabilitated and relinquished.
"Methane from gas, coal and oil extraction and distribution is driving the climate crisis - on top of the carbon dioxide that is emitted when these fossil fuels are burned.
"Scientists say cutting methane from fossil fuels is one of the most powerful levers we can pull to urgently cut climate pollution over the coming crucial decade."
