LONDON Two miners have been found dead and two others remain missing following a flash flood in a coal mine in south Wales, police and emergency workers said on Friday.
Rescue workers had found the body of one man overnight and later discovered the body of a second man another inside the small private Gleision Colliery in the Swansea Valley.
A fire and rescue spokesman they were hopeful the remaining two men were still alive and had found a place of safety within the mine.
"We maintain hope the entire time. This is very much a search and rescue operation," said Chris Margetts, from the South Wales Fire and Rescue Service.
The two dead miners have yet to be identified, adding to the trauma for families waiting for news in a nearby community center.
Three other men had escaped from the mine following the accident on Thursday and one was taken to hospital. They said a wall to an old working had failed, flooding the main 250 meter route into the mine.
Rescue workers found the body of one miner at the bottom of a shaft and the second dead man at the place where they had working at the time of the accident.
They have now cleared a way past a blockage caused when water had rushed in, and now had access to the main shaft at the bottom of the mine.
Crews would now start searching the "myriad" of tunnels and offshoots from the main shaft for the missing miners, Margetts said, adding it would be slow progress as they had to dig through silt and debris swept down by the flood.
"This is a terrible situation getting worse ... and it's been a terrible blow to the families," local MP Peter Hain told reporters.
"The only glimmer of encouragement ... is (that) there is no methane down below and there is oxygen. So if the other two miners have managed to scramble to a point where they have escaped the fall at least there is air circulating from which they can hopefully draw some sustainability," Hain added.
Wales, once famous for the mines in its valleys, has only a handful of remaining working mines, small and privately held, mostly supplying thermal coal for power stations.
Gleision Colliery is a private mine operating under a steep hillside above the banks of the river Tawe.
The colliery is a drift mine, a relatively low-cost form of underground mining, when tunnels -- drifts -- are dug horizontally into rock, rather than directly downwards.
Drift mines were known for being very dangerous in the past, with frequent accidents as tunnels caved in, and they remain risky.
(Additional reporting by Clara Ferreira Marques; Editing by Keith Weir)