Rix's Creek coal mine near Singleton will continue operating for another 21 years after the Independent Planning Commission re-issued its approval for the controversial extension.
The commission was forced to issue a retraction for an earlier approval granted on Friday October 4 because the period for public comment on additional information had not lapsed.
The bungle resulted in the commission allowing an extra week for comment on the material.
It's latest approval was issued at 1.30pm on Saturday afternoon.
Bloomfield Collieries lodged a state significant development application to expand its Rix's Creek south mine and continue open cut mining operations there until 2040.
It is estimated an additional 25-million tonnes of coal, worth more than $104 million in royalties, will be recovered from the mine over that period.
It will also employ an estimated 255 full time workers and 44 full time equivalent contractors. The value of wages would be $21 million annually
The matter had been referred to the commission due to concerns about noise and dust pollution as well as visual and heritage impacts.
In their statement of reasons the three commissioners reiterated their earlier view that the application was in the public interest to proceed.
The commission said it was satisfied greenhouse gas emissions had been "adequately minimised as far as practicable".
Planning Minister Rob Stokes welcomed the decision as "great news for the people of the Upper Hunter and the community of Singleton".