A miner who escaped alive from a flooded coal mine told a jury the force of the water was so strong that it pinned him to a wall.
David "Jake" Wyatt was working deep inside the Gleision drift mine near Pontardawe, south Wales, when explosives used to break the coal face unlocked 650,000 gallons of water.
The disaster claimed the lives of Philip Hill, 44, Charles Breslin, 62, David Powell, 50, and 39-year-old Garry Jenkins.
Pit boss Malcolm Fyfield, 58, and its former owners MNS Mining both deny gross negligence manslaughter charges.
Their trial today heard evidence from Mr Wyatt, who had been operating a conveyor belt inside the mine on September 15, 2011.
After the usual muffled sound from the explosives had subsided, the witness said what followed was a noise "like a jet engine".
The water, which experts estimate was travelling at 21mph, pinned him against a wall before he managed to crawl away.
And just a few feet away from the where the water had stopped, he then collapsed in exhaustion.
Fyfield, aged 58, from Caerhenllys in Cwmllynfell, who took over as manager in July 2011, denies four charges of manslaughter by gross negligence.
MNS Limited took over ownership of the mine in September 2009. They are represented in court by directors Gerald Ward and Maria Seage and deny four charges of corporate manslaughter.
The trial continues.