Rio Tinto has cut about 40 employees and contract workers from the Hunter Valley coalmine at the centre of a controversial court ruling last week.
Rio's permission to expand the Mt Thorley Warkworth mine was overturned in the NSW Land and Environment Court last week after residents from the town of Bulga succeeded in a long campaign against the project.
Rio had planned to expand the mine to the extent that open-cut operations came within 2.6 kilometres of Bulga and consumed land that advocates say was promised for conservation.
Rio announced on Monday that it would appeal the decision in the Supreme Court and said the result would prove crucial to the jobs of 1300 people.
Announcement of the appeal coincided with about 40 job losses from the mine on Monday.
Rio spokesman Darren Yeates stressed those job losses were part of a broader cost-cutting program, but were a reminder of how precarious the mine's future was under current conditions.
"Regrettably, 40 employees and contractors are either having their position made redundant or being let go from the site today, as part of this ongoing work," he said.