It was Wales' worst mining disaster in recent years.
A flood at Gleision Colliery in the Neath Valley claimed the lives of four miners; devastating the close-knit community and bringing back painful memories of previous mining disasters.
For thirty hours rescuers battled, hoping to find the men alive. A year on, we take a look back at that tragic event, and see how Wales responded.
Timeline of events
At 09.25 on the 15th September 2011, The Mines Rescue Service receives a call to say there has been an inrush of water at Gleision Colliery, near Cilybebyll in the Neath Valley, and that a number of men are missing. The details are still vague but the team quickly assemble and make their way to the site.
Three men have already made it out of the mine; but four are still below ground. Those miners are David Powell, Garry Jenkins, Charles Breslin and Phillip Hill.
The mine has been flooded by a huge quantity of water; and it is impossible to reach where the men are believed to have been working. It's a small space, and in places the mine is less than four foot high. Divers try to get through but can't. The rescuers set about pumping out the water.
The families of the four men gather at a nearby community hall, as Wales watches and waits. There are numerous deliveries of food and drink to keep them and the emergency services going.
Rescuers work through the night, but as time drags on, hope starts to fade.
By midday on the 16th September two bodies have been found. The families face an agonising wait to discover who they are. Any hope that had remained disappears, and at six o clock the rescuers confirm all four miners have died.
Over the last year, over a million pounds has been raised to help the families of the miners who died. The money collected by the Swansea Valley Miners Appeal was given out just a few weeks ago.