Smith said the area did have conservation values although it had been previously mined and was infested by gorse and broom.
Bathurst would pay $22 million for the "loss of conservation values."
This would fund pest and predator control over 25,000ha of the Heaphy River catchment in the Kahurangi National Park, 4500ha on and around the Denniston Plateau, as well as for historic projects on the Plateau itself.
It was the largest ever compensation package negotiated by DOC for a mine or other commercial venture.
"I am also satisfied that the comprehensive conditions associated with this access agreement covering rehabilitation of the land, enhancement of water quality, health and safety, debris, rubbish and fire hazards, will minimise the adverse effects of the mine," Smith said.
In late March, an interim decision gave tentative approval for the proposed Escarpment Mine, which planning commissioners said could potentially create hundreds of jobs but also result in the loss of rare native species.
Forest and Bird and the West Coast Environment Network appealed to the Environment Court after the Buller District Council and West Coast Regional Council granted the consents in 2011.
The court's interim ruling found that, even once rehabilitated after mining, the Denniston Plateau ecosystem would be "less fit, rich and diverse". The consents process remains before the courts.
Perth-based Bathurst last month shed staff as the struggle to work through the resource consents process took its toll.
The company currently employs about 70 people in Buller and has said it will ultimately have about 450 staff there, if the Denniston mine gets the nod.
