New Labour leader Jeremy Corbyn has told BBC Wales he does not want to reopen coal mines.
In an interview in August, Mr Corbyn said in future "high quality coal" in south Wales could be mined again.
But he told Radio Wales re-opening mines was not his policy. "It was one question about one mine, I'm not in favour of reopening the mines."
He said he wanted a "sustainable energy development policy, a green development in all aspects of energy generation".
He was speaking to Radio Wales after his first Labour party conference speech as leader, in Brighton on Tuesday.
Mr Corbyn - who has suggested corporation tax could be increased - also said there was not any "great difference" between him and First Minister Carwyn Jones on business.
In a lecture last Friday, Mr Jones said Welsh Labour and the Welsh government must be "fiercely pro-business" if Wales is to prosper.
Some in Welsh Labour fear party leader Jeremy Corbyn will make Labour more left-wing and hostile to private firms.
On Wednesday, Mr Corbyn said: "If we cut corporation tax, is that business friendly or is that not very sensible because you're cutting off an important source of income which can fund public services and crucially investment?
"If there isn't public investment, or publicly-directed investment, in infrastructure and industry then the jobs are not there, the opportunities are not there for business to develop and grow.
"I don't think there's any great difference between Carwyn and I on that, and indeed I want to see a growing economy, as does he," Mr Corbyn added.
He also said Wales should be proud of the diversity of cultural life and contributions made by migrants.
"There are many people who have come from all parts of the world and made their home in Wales and made an incredible contribution," he said.
Mr Corbyn's comments came in response to questions about the number of migrants coming into Britain and he said they made an "incredible contribution to our society" by working in the NHS, in education and university and research as well as opening and developing business.