Watch the full programme - as the man who led the Gleision investigation says nothing more could have been done to establish what happened.
Saturday marks the one year anniversary of the Gleision mining disaster
Tomorrow marks a year since the Gleision mining disaster, and the First Minister has led the tributes to the four men who lost their lives.
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
The families of four miners killed at the Gleision Colliery two years ago today say they are trying to move on.
They were speaking at the unveiling of a new memorial to the men, which has been placed near the pit in the Swansea Valley.
Today marks two years since the Gleision Colliery mining disaster in the Swansea Valley. Four men died after getting trapped underground when a tunnel they were working in filled with water.
It was the worst mining disaster in Wales in recent times.
Three men initially escaped and a search and rescue operation was launched to find the other four miners who were trapped 300 ft below the ground.
Philip Hill, 44, Charles Breslin, 62, David Powell, 50 and Garry Jenkins, 39 were all found dead the following day.
Carwyn Jones, Wales' First Minister described the deaths as "a tragedy for all of Wales."
On Friday, a memorial stone in recognition of the miners was unveiled at the former Tareni Colliery, a short distance from the Gleision site.
A memorial stone in recognition of the miners who lost their lives in the Gleision Colliery disaster will be officially unveiled today.
David Powell, 50, Garry Jenkins, 39, Charles Breslin, 62, and Phillip Hill, 44, lost their lives when the mine flooded in September 2011.
The stone is located on the site of the former Tareni Colliery, a short distance from the entrance of Gleision Colliery.
A man accused of causing the death of four miners in the Gleision Colliery disaster has appeared at Swansea Crown Court.
Malcolm Fyfield was the general manager of the mine when the incident happened in September 2011. He has been charged with four counts of gross negligence manslaughter.
Mr Fyfield was remanded on bail until May 20, when he will be expected to enter a plea of guilty or not guilty to the charges.
Also appearing in court were representatives of MNS Mining Ltd, which owned the mine at the time of the incident, to answer charges of corporate manslaughter.
Lawyers told the court that the company representatives would also not be entering a plea, and will also appear in court on May 20.
The manager of Gleision Colliery where four miners died, has been charged with gross negligence manslaughter. The four men were killed whilst working at the mine in September 2011.
The company which owns the colliery has also been summonsed to answer four counts of corporate manslaughter. Here's Richard Morgan.
– Detective Chief Inspector Dorian Lloyd, South Wales Police
Upon completion of the investigation and following consultation with the Crown Prosecution Service, the mine manager, Malcolm Fyfield has today been charged with four counts of gross negligence manslaughter.
In addition, a prosecution for four offences of corporate manslaughter against the owners of the mine, MNS Mining Ltd, is proceeding.
I would like to take this opportunity to express my sincere gratitude to all members of the local community for their continued support and understanding throughout this process.
A man has been charged with manslaughter following an investigation into the deaths of four men at Gleision Colliery in September 2011.
Malcolm Fyfield, 57, has been charged with four counts of gross negligence manslaughter and will appear at Neath Magistrates Court on February 1st.
The four men – Philip Hill, 44, Charles Breslin, 62, David Powell, 50 and Garry Jenkins, 39 - died after becoming trapped in the mine on 15th September 2011.