The Mount Penny proposal hit the headlines earlier this month with confirmation that its exploration licence - bought from the state government for $1 million less than a year ago - was being sold for $500 million.

The deal involves the stockmarket-listed White Energy buying the company controlling the Mount Penny site, Cascade Coal.

Craig Shaw, interim secretary of the Bylong Valley Protection Alliance, said landowners in the region were opposed to the mine, which was proposing to produce about 5 million tonnes of coal a year.

He said it would "run across some of the best agricultural land in the Valley".