Concern is growing over the future of jobs at Unity Mine - one of Wales' largest drift mines.
It follows a day of talks between the NUM and management of the mine in the Neath Valley, where around 200 people work.
The General Secretary for the NUM in South Wales, Wayne Thomas - who attended a meeting with Unity Mine managers this afternoon - said afterwards that there was uncertainty, but there had been no talk of the mine closing.
He added that there is likely to be a statement tomorrow on consultations over possible job losses and the mine's long-term future.
More top news
New figure show a record-breaking season for Welsh heritage sites, with more than 135,000 families paying them a visit.
An overcast and damp start for most. By lunchtime it should be mostly dry but the skies will stay largely cloudy.
A full-time carer from Port Talbot is celebrating after winning £1m on the EuroMillions.