South Wales Police has arrested a 55-year-old man in connection with the Gleision Colliery incident in Cilybebyll on 15th September 2011.
The man was arrested at an address in the Swansea Valley on Tuesday morning on suspicion of gross negligence manslaughter. He is currently in custody at Port Talbot Police Station.
Four men – Philip Hill, aged 44, Charles Breslin, 62, David Powell, 50 and Garry Jenkins, 39 – died after becoming trapped in the mine.
Their families and community leaders were updated with news of the arrest earlier today.
Police are working with the Health and Safety Executive to investigate the circumstances surrounding the deaths.
Examination of the scene is complete and the mine is now closed and under the control of the Coal Authority.
Detective Chief Inspector Dorian Lloyd of the South Wales Police Specialist Crime Team is the Senior Investigating Officer leading the investigation into the deaths.
DCI Lloyd said: “The arrest follows consultation between the South Wales Police, Health and Safety Executive and the Crown Prosecution Service to review the evidence gathered to date.
“We continue to work closely with the bereaved families throughout this process and I would like to express my sincere gratitude to the communities affected by this incident for their continued support and patience.
“We will do everything possible to fully understand how these four men lost their lives.”