Methane emissions from Hunter coal mines go sky high

Through the roof: A graph of methane emissions from Hunter mines. The spikes represent methane venting from underground mines.

Through the roof: A graph of methane emissions from Hunter mines. The spikes represent methane venting from underground mines.

More needed to be done to monitor and reduce the greenhouse gas emissions from Hunter coal mines, the authors of a study on methane emissions have found.

Associate professor Bryce Kelly and Charlotte Lverach from the University of NSW’s Connected Water Initiative recently carried out an analysis of methane emission’s from the region’s mines. 

The study, believed to be the first of its kind, was carried out using a methane monitor attached to the roof of a car.

While methane levels were found to be elevated near open-cut coal mines, they were particularly high near undergound mines, which vent the gas directly into the atmosphere.

They concluded that more work was needed to satisfactorily reduce the greenhouse gas footprint of coal mining, even before the coal is burnt to produce electricity.

“On some days methane concentrations above 2000 parts per billion extend for 50 kilometres near the coal mines. We have not encountered any other landscape with elevated readings extending for kilometres, with the exception of days where there are bushfires,” they wrote in The Conversation

Methane is a colourless and odourless gas. It has a global warming potential 25 times greater than carbon dioxide over 100 years. 

Apart from energy, major sources of methane include municipal solid waste, municipal waste water, agriculture, bushfires, termites, wetlands and natural seeps from the earth.

Associate professor Kelly said the study into Hunter mining emissions was not designed to identify issues associated with specific mines.

“Rather, that the coal industry as a whole can further improve the management of fugitive methane emissions from coal mining,” he said.

He said Australia’s greenhouse gas emissions needed to be recorded with greater accuracy.

“Australia needs a more extensive greenhouse gas monitoring network, so that we can reduce the uncertainty in our national greenhouse accounts and better track progress on our international emission reduction commitments,” he wrote in The Conversation

“Our research is focused on measuring what is actually being released into the atmosphere. This is vital for properly understanding how large our greenhouse gas emissions are and where to focus our efforts to reduce these.”

An Environment Protection Authority spokeswoman said the agency did not typically regulate the discharge of methane from licenced industries such as the state’s coal mines.  

“From a health perspective methane is a low toxicity, odour free gas,” she said.

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