A proposed coal mine's future green house gas emissions have been used as grounds to reject it by a NSW court.
A last-ditch effort by a company to get approval for a NSW coal mine has been rejected, with the Land and Environment Court citing the project's greenhouse gas emissions as grounds to reject it.
Justice Brian Preston on Friday dismissed Gloucester Resources Limited's appeal of the Department of Planning and Environment's 2017 decision to not approve the mine in the NSW Hunter.
Justice Preston said the Rocky Hill coal mine would increase global greenhouse gas emissions "at a time when what is now urgently needed ... is a rapid and deep decrease in GHG emission".
"In short, an open cut coal mine in this part of the Gloucester Valley would be in the wrong place at the wrong time," he said in his judgment.
"All of the direct and indirect GHG emissions of the Rocky Hill Coal Project will impact on the environment."
People in the packed courtroom quietly celebrated, hugging and shaking hands with each other, as Justice Preston delivered his judgment, with one opponent to the mine breaking down in tears.
GRL had argued the increase in gas emissions associated with the project would not necessarily cause the carbon budget to be exceeded.
However, Justice Preston said the reasons they used to justify that claim were "speculative and hypothetical".
"A consent authority cannot rationally approve a development that is likely to have some identified environmental impact on the theoretical possibility that the environmental impact will be mitigated or offset by some unspecified and uncertain action at some unspecified and uncertain time in the future," he said.
The company also suggested greenhouse gas emissions would occur regardless of whether the Rocky Hill project went ahead, because if coal demand was not met by Australian mines "investment will flow to other large coal producers and mines".
Justice Preston said that argument was "flawed" because there was no certainty the market substitution would be in the form of coal.
"Countries around the world are increasingly taking action to reduce greenhouse gas emissions in their countries, not only to meet their nationally determined contributions but also to reduce air pollution," he said.
Aside from its GHG emissions, Justice Preston also pointed to the visual impacts the mine would have on the local community, the noise and dust it would create.
He said these issues outweighed the economic and other public benefits of the coal mine.
The Land and Environment Court decision was lauded by Climate Council chief executive Amanda McKenzie.
"The NSW Land and Environment court has effectively ruled that coal - just like tobacco and asbestos - is bad for us," Ms McKenzie said in a statement.
"I'm thrilled to see the law catching up with the science."