A "game-changing" court decision blocking a coal mine in part because of its climate change impacts will stand after the project proponent dropped plans to appeal against the verdict.

Gloucester Resources had until Wednesday to oppose the rejection by the NSW Land and Environment Court in February of its proposed Rocky Hill coal mine near the town of Gloucester on the state's Mid North Coast.

A win is a win - finally: Gloucester residents opposed to the nearby Rocky Hill coal project proposal may finally get some peace. Credit:Janie Barrett

In a short statement, the company said it had "decided not to pursue its appeal options" through the Court of Appeal.

"This means the Rocky Hill Coal Mine will not proceed," it said, adding the company would carry out "further assessment of its current exploration licences in the area".