Two "biodiversity hot spots" were being considered, Whareatea West, which had the highest value ecosystem on the Denniston Plateau, and Deep Creek above Waimangaroa.
Opencast mining was proposed at Whareatea and underground mining at Deep Creek.
A haul road was proposed to take coal from the Denniston Plateau to Stockton for coal processing.
The Government talks were well advanced and it was unclear when the public would be involved.
The Government was promising money and jobs. The same promises were made for Bathurst's Escarpment Mine at Denniston, Hague said.
Escarpment went into care and maintenance last year because the international coking coal price collapsed and the mine had no New Zealand customer.
The West Coast Regional Growth Study, released last year, proposes allowing mining in specific areas of the Buller Coalfield, subject to environmental conditions.
Hague said he wouldn't support that, because too many ecosystems had already been lost.
"I get there's jobs at stake and the rest of it. But as I've said, look at Escarpment, where pretty much all the damage has been done but none or the benefits delivered...
"Stockton, for a while, delivered high value jobs but for the most part it's a really short-term phenomenon."
Economic Development Minister Simon Bridges said the proposals were an "ongoing matter that ministers continue to discuss".
"It is a difficult issue as Buller Plateau has significant economic value but we also understand the need to balance that with the conservation issues."
Hague said those comments were "kind of laughable".
"The point of balance was passed a long time ago, arguably a century ago, in terms of how much we could afford to lose."
Eco-systems on coal measure geology were unique, he said.
But Buller Mayor Garry Howard said there was nothing "secret" about the proposal to set environmental conditions on coal mining so miners knew where they stood.
Nor was there any secret mining plan - the Government wanted to set a high bar for environmental standards to allow for coal mining, he said.
"This establishes certainty for companies looking to mine and could save many millions of dollars companies and environmentalists currently spend going through the RMA (Resource Management Act) process where the outcome is unknown.
"New Zealand has an opportunity to have responsible mining with set conditions as opposed to many countries with few environmental controls."
Howard said the proposals went back to 2013. They were spurred by Bathurst's struggle to gain consent for Escarpment Mine.
The company took several years and reportedly spent $15 million on the process.
Howard said his council had subsequently suggested setting environmental conditions for mining in certain areas. Something had to change for coal mining in Buller to have a future.
"Companies were not going to repeat the process of Bathurst."
Hague was negating international conservation efforts, by opposing coal mining under good environmental conditions, he said.
"On an international basis, are you not better to say we can do it and do it well, rather than have it happen in a country that's got no environmental conditions?"
Coal was being portrayed as something New Zealand didn't like or need, Howard said.
"The reality is, coal is a required commodity in the world in the current market today."
Coal was required for steel making and many other products, such as activated carbon.
Hague said coal use was declining as the proportion of recycled steel increased and new steel production technology became available.
"Our concern is around the protection of this particular [Buller coalfield] co-system, as well as New Zealand's responsibilities around climate change... We do care what happens overseas as well."
- Westport News
