Officials are investigating a proposal which could lead to the Pike River mine being turned into an opencast coal pit stretching into a national park.
The proposal from Solid Energy seeks permission to change its mining and prospecting permits to investigate the best way of making the mine profitable - including "consent for an opencast mine in or adjacent to the [Paparoa] National Park".
The application seeks permission to investigate whether an opencast mine is viable - raising questions over whether the Government is returning to its controversial plan to mine sensitive conservation land.
Further work would be needed, along with government backing, to turn the defunct underground mine at which 29 men died into a larger open mine.
Energy and Resources Minister Simon Bridges refused to respond to questions about whether opencast mining on conservation land was again an option. He said it was "hypothetical" - even though officials at the Ministry of Business, Innovation and Employment have been studying the application for eight months.
The proposal from Solid Energy follows the discovery of its parlous financial state and the loss of about 400 jobs at mines on the West Coast at Spring Hill and Pike River.
Grey District Mayor Tony Kokshoorn said: "There's only one feeling on the West Coast - if we can opencast it then we should opencast it. Everyone is in favour of it if it is feasible."
He said mining had been the "jewel in the crown" of the West Coast economy until recent layoffs and an opencast Pike River could give access to a rich seam of coal boosting the local economy and employment.
Solid Energy applied for the change to its permit in June last year as it prepared to buy out Pike River mining company. The application, released under the Official Information Act, sets out a work programme to find a "financially credible" way to extract coal.
It found the amount of coal available was "much lower than that indicated by Pike River Coal" with the most abundant and easiest to access deposits at a "relatively shallow" depth of 50m-150m.
The application stated the area was "highly challenging" although Solid Energy had "considered an option for an opencast mine in the shallower areas of the [mining] permit, allowing for mining the escarpment within the Paparoa National Park".
It stated an opencast mine could only go ahead with "removal of the constraints implied by the national park". Solid Energy said it would also need Department of Conservation approval to explore "the entire Pike River coalfield in the national park".
Opposition MPs called on Mr Bridges to be clear about the Government's position on mining in conservation land. West Coast Green Party MP Kevin Hague said the application showed major industrial activity in the national park. "That's absolutely forbidden. It could only happen if Simon Bridges makes it happen."
Labour's conservation spokesman Ruth Dyson also called for Mr Bridges to be clear. "If they're against it, why not tell Solid Energy not to waste their time."
A spokesman for the Ministry of Business, Innovation and Employment said the application from Solid Energy was to "allow it to investigate a range of potential future mining options [including opencast mining]". He said the application was still being considered.