The two-year rehabilitation of Australia's oldest open-cut mine site at Muswellbrook is underway.
The Muswellbrook Coal Mine's open-cut operations began in 1944 and continued until mid-2022.
The site's owner, Idemistu, has prepared a masterplan for the area with a view to transforming the old pit into an energy training and industry precinct.
It will also incorporate green hydrogen, solar and pumped hydrogen, a key part of the company's efforts to reduce its carbon emissions by four megatonnes and generate four gigawatts of renewable energy by 2030.
Thiess Rehabilitation, which has been awarded the mine rehabilitation contract, will conduct detailed design and construction of the post-mining landform.
It plans to create a combination of native ecosystem and pasture land uses that generate about 180 hectares of rehabilitated land across the mine site.
Thiess Rehabilitation group manager James Anderson said the Muswellbrook Coal Mine had special significance for Thiess.
"The mine's open-cut operations began in 1944 and that contract was awarded to our founders, the Thiess Brothers, marking both the start of Thiess' mining business, as well as the start of Thiess' presence in the Hunter region," he said.
"Given our legacy at Muswellbrook Coal Mine, Thiess Rehabilitation is excited to be given the responsibility to deliver value to this site and to the community through the site's post-mining transition."
Muswellbrook Coal has been owned by Idemitsu since 1989.
"Now that mining and processing operations have been completed at the site, Idemitsu is progressing plans to develop the Muswellbrook Clean Industries Precinct at the site," Idemitsu's chief executive Steve Kovac said.
"A critical part of these future plans is the rehabilitation of the mining operational areas, and we are pleased to have a specialist with proven experience to help deliver our rehabilitation goals."
The mining void can hold six gigalitres of water (by comparison Grahamstown Dam holds 182 gigalitres). Water would be pumped 2000 metres to the top of Bells Mountain where it would be stored in a 1.9 gigalitre reservoir that would be created on the top of the mountain. It would flow using gravity through pipes to drive a turbine at the base of the mountain.
Pumped hydro energy storage constitutes more than 94 per cent of electricity storage worldwide. The five NSW projects, which include Muswellbrook, would have a potential combined capacity of almost 1.75 gigawatts.