The man in charge of the investigation into the Gleision Colliery disaster has said that nothing more could have been done to establish what happened.
Speaking exclusively to ITV Cymru Wales for tonight's Wales This Week programme, the Acting Chief Inspector of Mines Steve Denton said he is satisfied that the Health and Safety Executive did everything it could.
That comes despite criticism, from the families of the four miners who died in September 2011, that they were not thorough enough - and a public inquiry is now needed.
There is much more on this story on:
Wales This Week, tonight at 10.35pm on ITV Cymru Wales
Y Byd Ar Bedwar, tonight at 9.30pm on S4C
More top news
This year sees major changes to the ITV Welsh Politician of the Year Awards, the highlight of the political calendar in Wales,
The public are to vote on which destination they would like to be crowned 'Best Place' in Wales.
The father of a 21-year-old woman who is accused of imprisoning his daughter in fails in bid to stop the media reporting the case.