KEPCO, which spent a decade trying to get the greenfield mine approved before its refusal, appealed the IPC decision late last year.

The IPC originally rejected the South Korean Government-owned KEPCO's planned coal mine due to its "long-lasting environmental, agricultural and heritage impacts", however KEPCO later appealed that decision.

In its decision, the IPC based its refusal on environmental impacts other than climate change, including impacts on agricultural land, groundwater and Aboriginal cultural heritage. But ultimately the IPC found the contribution to global greenhouse gas emissions was a factor that needed to be considered in its assessment, and pointed out the applicant's failure to suggest any offset measures.

The decision at the time prompted Mid-Western Regional Council Mayor Des Kennedy to pen an op-ed in September 2019 calling for an 'end to the uncertainty'.

"The project proposed by KEPCO provides our communities with a 25-year pipeline of jobs and long-term economic and social benefits," Cr Kennedy said at the time.

"The closure of the Kandos Cement Works, the Charbon mine, quarry and all those other businesses which supplied these major operations have forced locals to look elsewhere."

The Bylong Valley Protection Alliance - a community group including farmers from the productive agricultural valley - then took the unusual step to defend the IPC's decision in court in response to KEPCO's appeal, after the IPC chose not to defend it.

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KEPCO persisted with its appeal, even after writing off the $700M value of the mine.

"This court decision reaffirms what we locals always knew - that the IPC was right when it ruled the agricultural values of this valley are too precious to sacrifice for the sake of a temporary, destructive coal mine," Bylong Preservation Society president and Bylong farmers Phillip Kennedy said on Friday.

"What we'd like to now see is the NSW Berejiklian and Barilaro Government permanently rule out mining in the Bylong Valley, and protect it for farming in perpetuity through legislation.

"This is a win for Australian agriculture during particularly uncertain times."

Speaking with the Mudgee Guardian on Monday, Phillip said it was a win for 'common sense'.

"It's a great win for Bylong, but also it reached beyond this. It's a win for Australian Agriculture and also a win for Australian-owned businesses," he said.

"People tend to forget these are foreign entities that are doing this. Mining is 80-dd per cent foreign-owned in Australia and yet you have three levels of government bending over backwards welcoming them into the country.

"Particularly in times like this when trade is scratchy. But it's a great win, it's a fantastic Christmas present, everyone in the valley seems to be very happy with it."

Phillip is one of the remaining few farmers left in the Bylong area, having called Bylong home for roughly two and a half years after moving from Nyngan.

Phillip runs a mixed agricultural enterprise, mostly made up of cattle, lambs, hay and grain.

"There's not too many of us left now, there's sort of half a dozen farmers here. We've fought pretty hard to keep it as an agricultural valley and they're overjoyed by it," he said.

"We just hope that's the end of it, that we don't have to this again and again and again with more appeals.

"Will they take their pill and swallow it? I don't know."

The Mudgee Guardian reached out to KEPCO for comment, which said it was disappointed with the ruling.

'The NSW Land and Environment Court handed down its decision... following a judicial review of the Bylong Coal Project. KEPCO is very disappointed that the Court did not find in favour of the Project and the strong case it made for overturning the refusal by the IPC. KEPCO will now take some time to review the decision of the Court and decide the future direction of the Project,' KEPCO said.

The BVPA has called on KEPCO to sell the 30,000 acres it bought in the valley back to the people.

KEPCO claimed the mine would create more than 800 direct and indirect jobs, with nearly $280 million in royalties to the NSW Government and $600 million in annual business turnover.