The inquest into the deaths of four men killed in a South Wales mining disaster 13 years ago will have a “forensic and laser-like focus” in answering key questions about the case, a coroner has said.

Garry Jenkins, 39, Philip Hill, 44, David Powell, 50, and Charles Breslin, 62, were killed when thousands of gallons of water flooded the Gleision drift mine, near Pontardawe, a town in the Swansea valley, on September 15 2011.

Seven men were working in the tunnels that day and only three survived.

The mine’s site manager, Malcolm Fyfield, and the company that ran the mine, MNS Mining Ltd, were acquitted of gross negligence manslaughter by a jury at Swansea Crown Court in 2014.

Following the trial, the victims’ families successfully campaigned for a full inquest into the deaths and this was opened in December 2022.

A pre-inquest review hearing took place at Swansea Guildhall on Friday in front of Edward Ramsay, assistant coroner for Swansea and Neath Port Talbot.

Mr Ramsay told the court that members of the victims’ families had attended the hearing in person and online.

“I want to acknowledge them – their grief, their loss,” he said.

“I want to thank them for their attendance today. I want to reassure them.

“There will be nothing slip slop or perfunctory about this inquest.

“I am already of the view that this inquest needs a forensic and laser-like focus on answering where the water came from and who, if anyone, knew or ought to have known it was there.”

The coroner said he had been studying documents about the case including those relating to the criminal trial, and detailed maps of the area.

He told the court: “No stone will be left unturned. I will go wherever the evidence takes me.”

A further pre-inquest review hearing has been scheduled for April 25 next year, with further such hearings expected to take place before the full inquest.

The disaster happened after a routine blasting, and the families and friends of those trapped waited for hours inside Rhos Community Centre nearby as divers searched in vain for survivors in the murky, dark water.