THE SOUTH Wales boss of a coal mine who survived an horrific underground flood in which four colleagues died is due to appear in court for a plea hearing accused of their manslaughter.

Malcolm Fyfield, 57, was manager of the Gleision mine, in the Swansea Valley, when disaster struck in September 2011.

Philip Hill, 44, Charles Breslin, 62, David Powell, 50, and Garry Jenkins, 39, all died when they were engulfed in a half-a-million gallon torrent of water.

Fyfield, who was underground at the time but managed to crawl to safety, was taken to hospital and spent up to a week in intensive care recovering.

He was later charged with four counts of gross negligence manslaughter in connection with the tragedy and remains on conditional bail.

MNS Mining Limited, which owned the Swansea Valley mine at the time of the disaster, also faces four charges of corporate manslaughter.

Fyfield, and representatives for the company, will appear at Swansea Crown Court today for a plea and case management hearing.

Judge Wyn Williams has previously set a provisional date of March 24 for what, if it goes ahead, is expected to be an eight-week trial.