The Hunter Valley Operations (HVO) extension approval meant more than ongoing employment opportunities; it secured the future of one of the region's tight-knit communities.
Many of the mine's 1500 employees gathered at Lemington on Thursday to celebrate the news that the mine would continue to operate into the 2040s.
"This isn't just somewhere where I come to work - it's where I live, where my family is growing up and where I see our future," mine services supervisor Corey Ayre said.
"Mining is often talked about in tonnes, dollars and production figures, but behind all of those numbers are people - families, apprentices, contractors and local businesses that rely on the industry."
HVO general manager Dave Foster told the jubilant workforce that federal government approval was needed before the extension to the state's largest mining project was fully approved.
"I've lived in Singleton my whole life, in the Hunter Region, and I've never seen the community rally around a business, a project, like this," he said.
"This is a big milestone for us, but we've got one more milestone left to go, and that's the federal approval in the next month or two."
The Independent Planning Commission's (IPC) Wednesday approval for the project didn't come without several key conditions.
There is a requirement for HVO to take steps to limit coal exports to jurisdictions that have policies for reducing greenhouse gas emissions consistent with the goals of the Paris Agreement, maximise the use of renewable energy at the mine and purchase additional carbon offsets.
The IPC also imposed conditions requiring a comprehensive closure management plan to be prepared within one year, implemented and reviewed every three years.
The Hunter Jobs Alliance said approval and the associated conditions should be a wake-up call for mining companies and state and federal governments about the need to properly plan for coal workers and communities.
"The IPC has confirmed what HJA has been saying for years - you cannot wait until a coal mine is closing to start planning for its workers and community," Hunter Jobs Alliance coordinator Justin Page said
"Transition planning has to start early, be properly funded and deliver real support. Mining companies cannot point to the threat of job losses and socioeconomic impacts on communities while failing to adequately plan for those very impacts."
Mr Page called on the project's owners Glencore and Yancoal to fund the necessary support for workers.
"They are large multinational mining companies that have benefited enormously from generations of Hunter coal workers and communities," he said.
The NSW Government must legislate those obligations and invest substantially more coal royalties back into coal communities; and the federal government must close the gap in transition support for export coal workers."
Mr Foster confirmed on Wednesday that HVO would begin work on a closure plan.
"I think it's important to note that we look after our workforce and that is our priority," he said.
"We have a new condition to produce a closure plan and we look forward to working with Muswellbrook and Singleton councils on the development of that plan."
