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
Wales reached their first ever semi-final of a major tournament with a magnificent 3-1 victory over Belgium in Lille.
There'll be clear spells overnight which means temperatures will fall. Setting us up for a dry start to the weekend, but it won't last!
Watch the men who have been making history by taking Wales to the quarter-finals of the European Championships.