The Hunter's massive mining voids could become the home for the next generation of data centres, a clean energy industry expert believes.
The temperature at the bottom of some voids, which are hundreds of metres deep, can be several degrees cooler than at the surface.
The temperature variation has the potential to save on water cooling, a key consideration in the establishment of the water and energy-intensive industry.
"We've got these well designed spaces at the bottom of the pits. Why wouldn't we be looking at using it for industrial purposes rather than filling it in and pretending it will be great agricultural land," co-founder of the clean energy advisory firm Energy Estate Simon Currie said.
"Most of them are close to the grid and it's a lot cooler and stable down there so you don't need as much water."
Data centres have already been successfully installed in mining voids overseas including in a former limestone mine in Pennsylvania, US.
Located 67 metres beneath the surface, the Iron Mountain Data Center utilises a 35-acre underwater lake to absorb the hot water expelled by the server racks.
Mr Currie said he was aware that some mining companies were considering hosting future data centres as part of their mine closure plans.
BHP, which is scheduled to close its Mt Arthur mine in 2030, is considering a range of options for the site.
"BHP is working with government, industry and the community to look at how the land and existing infrastructure at Mt Arthur Coal could continue to support economic activity and employment when mining ceases in 2030," a BHP spokesman said.
"That could include infrastructure to support new industries, training opportunities, energy projects, or other uses that help create long term value for the region."
In addition to hosting data centres, the Hunter's network of mining voids has previously been identified as potentially suitable for an inland lakes system.
Hunter Lakes Corporation has been developing the project, which would resemble the Lusatia Lakes District in eastern Germany.
The Newcastle Herald reported on Wednesday that an international technology and infrastructure consortium was about to lodge plans for a $10 billion data centre and battery system at Muswellbrook.
The proposed two gigawatt battery would be the largest in Australia. Half of the battery's output would be dedicated to powering the data centre.
Energy Estate is spearheading a project to connect the United States to Australia via a new subsea data cable.
The CaliNewy cable would run from the San Luis Industrial Complex in Northern California to large-scale industrial precincts in Australia and New Zealand.
Mr Currie said the cable would facilitate data centre growth in regions such as the Upper Hunter.
"The Hunter is relatively well connected from a fibre point of view, but in order to have the scale of data that we're talking about," he said.
"The next step for the Hunter is to get more fibre capacity. That is cheap compared with water and power and compared with transmission.
"We need to bring the data to the power, not the other way around. We need to work out how we get the industry to look beyond Macquarie Park (Sydney) and the outskirts of Melbourne."
