Conservation Minister Nick Smith announced his approval for an access agreement for the Escarpment Mining project under the Crown Minerals Act.

The approval follows a lengthy consent process riddled with environmental appeals and is a crucial milestone for the mine’s approval process.

The mine still requires consents under the Resource Management Act ,which remains subject to an Environment Court decision.

Smith clarified in the statement that the area is classified as general stewardship land, which the lowest legal status of protection of land managed by the department.

He said the area is not a National Park, Conservation Park nor does it have any particular reserve status.

The access approval is for a mine area of 106 hectares of the 2026ha that comprise the Denniston Plateau and udne rthe terms of the approval, Bathurst will pay $22 million as compensation for “the loss of conservation values” in what Smith called “the largest ever compensation package negotiated by DOC for a mine or other commercial venture.”

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.

“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. The agreement also contains detailed provisions for monitoring environmental effects, bonds and insurance,” Smith said.

“I wish to signal, that in giving this approval, I do not consider it is acceptable to open-cast mine all of the Denniston Plateau. The plateau does have unique biodiversity and landscape values from its raised elevation, high rainfall and unusual land form. I wish to see some of the high value areas reserved and put into permanent protection.”

Australian based, ASX-listed Bathurst said on its website that the Escarpment project will provide 225 jobs, contribute $1 billion to the New Zealand economy and pay for environmental and conservation projects for decades to come.

It said production will commence at 500,000 tonnes of export coking coal each year, increasing to 1 million tonnes as further infrastructure is developed

The project was granted resource consents in August 2011 but the decision was appealed by environment groups to the Environment Court.

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.

Bathurst went into a trading halt on the ASX on Thursday morning.