THE manager of the Gleision mine has been charged with manslaughter over the disaster which claimed four lives.
Malcolm Fyfield faces four counts of gross negligence manslaughter and will appear at Neath Magistrates' Court on February 1.
The company which owns the colliery and had employed him, MNS Mining Ltd, has been summonsed for four counts of corporate manslaughter, and a representative of the firm will appear in court on the same day.
Philip Hill, 44, Charles Breslin, 62, David Powell, 50, and 39-year-old Garry Jenkins became trapped when water engulfed the mine they were working in just after 9am on Thursday, September 15, 2011.
Despite a desperate search and rescue operation by police, firefighters and mines and cave rescue experts, the four trapped men perished.
South Wales Police superintendent Phil Davies said the Gleision case had been a complex investigation involving more than 40 officers, who had collected 300 statements and gathered 450 pieces of evidence.
Speaking at a press conference at Neath Civic Centre yesterday, he said: "Since the tragic event, South Wales Police have been conducting a full investigation into the deaths.
"No stone has been left unturned in relation to finding out what happened on that tragic day."
Detective chief inspector Dorian Lloyd from the force's specialist crime investigations team led the probe into the deaths, along with the Health and Safety Executive.
He said the aim of the investigation had been to establish "a full understanding of the events that led to such devastating loss of life".
He also praised the courage of the families of the four miners.
"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," he said.
"In particular I would personally like to thank the families involved for their unwavering patience and courage, and request that their privacy is respected at this very difficult time."
It is estimated that more than half a million gallons of water entered the section of the mine where the men were working in just three minutes.
Mr Fyfield managed to scramble to safety through an old entrance but was seriously injured.