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
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Mainly dry with lengthy clear spells overnight and just a few showers likely, especially in the north and west.
Ysgol Uwchradd Caergybi became the UK's first comprehensive 65 years ago. Academies are now dominant in England, but certainly not in Wales.
Dry for most, but a few showers likely.