Nant Helen mine to be mothballed with the loss of 75 jobs
An opencast mine in Powys is to be mothballed for two years with the loss of 75 jobs.
Celtic Energy is closing Nant Helen, Coelbren, because Wales' biggest coal-fired power station, Aberthaw, is downgrading its operations from April.
A consultation on the closure was held with unions in June and July who called the decision "sad but not unexpected".
Nant Helen is Celtic Energy's largest operational site and has about three million tonnes of coal in reserve.
Of the 91 employees at the site there will be 31 voluntary and 44 compulsory redundancies, while a small team will stay on to carry out security and maintenance operations.
Mike Macdonald, negotiations officer with Prospect union, which represents around dozen engineers at the site, said the decision was "not the employer's fault".
He added: "The site had been run down with the intention of restoring it in the future - and now it is going to be shut down before any finance has been raised.
"It all stems from UK government policy towards coal-fired energy generation [wanting all coal-fired power stations to close by 2025].
"The optimistic view is that we get clarity on the future of the industry at the end of this autumn.
"But we fear that it is inevitable that the skills will decline as people find other work - and we won't have the skills needed to keep the mines working.
"When jobs do reappear, they tend to reappear outside the area, and alternative employment is very slow at coming in."
Will Watson, chief executive of Celtic Energy, said the company "is confident the site will recommence coaling operations in approximately two years".
In October 2015, the firm announced it would mothball its opencast coal site Selar, near Glynneath, for three years, resulting in 70 people losing their jobs.
It said it could not keep the site running along with Nant Helen and the expanded East Pit.