The owners of a coal mine shutting within months could potentially lose a massive asset while their plans for a vital renewable project await approval.
The Stratford Pumped Hydro and Solar project in the NSW Hunter region is one of six developments declared critical state significant infrastructure in July.
It would take advantage of existing mining voids and infrastructure from a Yancoal mine closing in 2024.
But the company is still pushing ahead with plans to rehabilitate the closed mine, including filling in holes that would form the basis of the renewable development, representatives told a NSW parliamentary inquiry into post-mining land use on Monday.
"Even though the pumped hydro and solar facility was declared to be critical state significant infrastructure, there's no guarantee that we will get an approval," Yancoal approvals manager Michael Moore said.
The coal producer's policy specialist, Nick McDermott, said miners were not looking to sidestep their obligations, despite "healthy scepticism" amongst the MPs overseeing the inquiry.
"What we're looking at is finding better efficiencies in a process that everyone at a high level seems to recognise is a good idea … not to use this as a Trojan horse to minimise rehabilitation obligations," he said.
NSW Minerals Council chief executive Stephen Galilee said without change to allow for newly identified potential post-mining uses, opportunities could be missed.
However, decline in global demand for Australian coal would happen more slowly than some people might want or expect, Mr Galilee said.
"Our policy is to keep people in coal-mining jobs as long as possible," he said.
NSW Minerals Council policy director Claire Doherty said the system needed to make other potential post-mining land use attractive.
Pumped hydro-electricity proposals could benefit when there is already a hole in the ground.
"That's a massive asset to a project," she said.
But it was not identified as a potential post-mining land use in research the council conducted in 2014.
"It just shows you how quickly things can change and we need to be able to respond to that," Ms Doherty said.
NSW Resources deputy secretary Georgina Beattie told the inquiry emerging renewable sectors were bringing opportunities, but mines were still bound to their previously agreed final land use.
"If there's an opportunity to accelerate or make it easier to change that final land use that could incentivise companies, both investors and the mining industry, to look at those alternatives," she said.
BHP's vice-president of NSW energy coal Liz Watts said feasibility studies were being done for pumped hydro at the mining giant's Mt Arthur mine in the Hunter region, which is due to stop operating in 2030.
"To date we haven't identified any fatal flaws, and we've identified that it could potentially be quite a significant energy source into the future," Ms Watts told the inquiry.
