Gwenda Thomas AM raises concerns about East Pit resort plan
Plans for a £35m country park and resort on an opencast mine site should be referred to ministers, says an assembly member.
Developers hope to create 200 jobs at East Pit, Amman valley, with a lake, hotel, holiday lodges and dive school.
Neath AM Gwenda Thomas wants ministers to call in the plan due to concerns over its impact.
Consultants say failing to redevelop the site would be an "incredible missed opportunity".
They say the project would create 200 full time jobs and help pump £40m each year into the Neath Port Talbot economy.
The plan would not be fully realised for some time because East Pit's coal reserves would take around five years to exhaust.
Ms Thomas has written to the Welsh government's Environment Minister John Griffiths to raise her concerns.
She said the size of the site meant its impact was "likely to extend well beyond the immediate locality and the boundaries of one county borough".
"Given the site's proximity to the Brecon Beacons National Park, the proposals are likely to have a significant effect on a landscape of natural importance," she said.
"This is particularly so in relation to the proposals for the restoration of the site, which the applicants hope will create a development that will act as a gateway to the national park."
She said the proposals had created controversy locally and this was likely to increase.
Reasons for this included the effect on nearby communities and speculation over the "feasibility of the restoration of the site", she said.
The scheme is at an early stage with outline plans submitted to Neath Port Talbot council before Christmas.
The planning application also includes proposals for the final stages of coal recovery from the mine, which is operated by Celtic Energy.
Coal reserves are due to be exhausted at the mine in around five years but an extension is required for the last three of those years.
Paul McTernan of SLR Consulting, which is working on behalf of East Pit owner Oak Regeneration, said the regeneration scheme would bring great benefits to an area that badly needed investment.
"We spent a lot of time with people in the village halls. They are anxious and that's understandable," he said.
"But there's an incredible missed opportunity if we don't use the site for new forms of economic activity."
He said the mine, which employs 125 people, was going to close anyway so the tourist resort would help fill the economic gap.
He pointed to projects in England such as the Cotswolds Water Park and Thorpe Park where former mineral sites had been transformed into major destinations.
Brecon Beacons National Park Authority said it did not want to comment on the proposals at such an early stage.
Neath Port Talbot council said the application was currently "subject to consultations and publicity", with the next stage being the consideration of the responses.
The project is being developed with the Land Trust charity, which would take on the management of the site under a 99-year lease.
Oak Regeneration also owns the Margam opencast mine in Neath Port Talbot and has unveiled plans to build a "garden city" at the location.