Caedean Slant explosion, 1909

Date	22 October 1909
Mine	Trimsaran Colliery
Region	Carmarthenshire
Type	Explosion
Fatalities	4 (Owen Thomas, collier, of Glasfryn House (30, or 38 at the inquest); Edward Andrew 'Ted' Darke, 36, collier; John Williams, 16, collier's boy; David Sparry, 16, collier's boy. All died of burns and shock in the days after the explosion.)
Injuries	Four more of the eight were burnt. The Carmarthen Weekly Reporter names the injured, besides Darke and Sparry, as Evan Davies, the fireman in charge of the night shift; William Evans, shotman; Joseph Williams; and John Henry Griffiths, pumpman.
Context	During active mining (One of Trimsaran Colliery's three drifts near Kidwelly, working anthracite. Much of the mine was under water, and only eleven men were underground that night.)

In the early hours of 22 October 1909 gas exploded in the Caedean slant at Trimsaran, near Kidwelly, among eight men cutting a new airway through the coal. The colliery had recently been flooded, and the airway was meant to improve poor ventilation and help clear the water. The gas was thought to have been fired by a spark from an electric pump motor nearby. All eight were burnt. Four died over the following week: Owen Thomas, Ted Darke, and two collier's boys of sixteen, John Williams and David Sparry.

Cause

An accumulation of gas, presumed to have been ignited by an electric spark from the commutator of a pump motor close to where the men were working.

Contributing factors

A large part of the mine was under water, and the new airway was being driven through the coal to improve poor ventilation and to get rid of the water. The electric pump motor was close by. Gas was known to be present in small quantities.

What happened

The explosion came on the night shift, between three and four in the morning, while the men were working over the top hole in the new slant. The only people underground near the place were those it burnt, so the newspaper could get no first-hand account; the fireman in charge, Evan Davies, was among the most seriously hurt. Dr Howell attended the men, who were taken to their homes. John Williams died on the Saturday and Owen Thomas on the Sunday; Darke and Sparry died later.

Investigation & inquiry

The inquest opened at the Tabernacle vestry, Trimsaran, before the deputy coroner W. W. Brodie of Llanelly, with Mr Randell for the Miners' Federation and Mr Graham and Albert Jones for the company, and was adjourned to 14 December. The manager, Thomas Evans, said only eleven men were underground that night because so much of the mine was flooded.

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

An explosion in the Caedean slant on 22 October 1909 killed four: Owen Thomas, 30, John Williams, 16, David Sparry, 16, and Ted Darke, 36. ¹
Eight men cutting a new airway through the coal, the colliery having recently been flooded, were burnt by an explosion of gas between three and four in the morning; the gas was presumed to have been fired by an electric spark from the pumps. ^2,3
Welsh Coal Mines gives Owen Thomas's age as 30; at the opening of the inquest the witness identifying him gave it as 38. (disputed) ^2,3
The Carmarthen Weekly Reporter of 29 October says John Williams died on the Saturday and Owen Thomas on the Sunday, and that Ted Dark had since died; it still listed David Sparry among the injured. Welsh Coal Mines gives Darke's death as the 25th and Sparry's as the 29th. ^2,3
Welsh Coal Mines calls it the Caedaen or Cadean Slant of Trimsaran Colliery; the newspaper calls it the New Gaederen Colliery of the Trimsaran Company. ^2,1,3

Related terminology

Mining terms this disaster is structurally linked to, with the nature of the relationship.

Colliery (contextual relationship)
Named in this record’s summary: “…Kidwelly, among eight men cutting a new airway through the coal. The colliery had recently been flooded, and the airway was meant to improve poor…”
Deputy (contextual relationship)
Named in this record’s investigation: “The inquest opened at the Tabernacle vestry, Trimsaran, before the deputy coroner W. W. Brodie of Llanelly, with Mr Randell for the Miners'…”
Firedamp (direct cause)
Gas fired by a spark from a pump motor.
Fireman (contextual relationship)
Evan Davies, the night-shift fireman, was among the burnt.
Slant (contextual relationship)
Named twice in this record, first in the summary: “In the early hours of 22 October 1909 gas exploded in the Caedean slant at Trimsaran, near Kidwelly, among eight men cutting a new airway…”

Sources

(secondary) Trimsaran Colliery — Welsh Coal Mines
(secondary) 1909 fatalities — Welsh Coal Mines
(primary) 'Mine Explosion at Trimsaran', The Carmarthen Weekly Reporter, 29 October 1909 — Welsh Newspapers Online, National Library of Wales

Record created: 11 September 2026 · Last researched: 14 September 2026