St David's Colliery explosion, 1840

Date	27 June 1840
Mine	St David's Colliery
Region	Carmarthenshire
Type	Explosion
Fatalities	6 (Henry Lewis, 17; William Williams, 20; Thomas John, 10; William Hugh, 25; Griffith Morgan, 14; and David Samuel, 14, who died on 15 July. Welsh Coal Mines describes the immediate dead as three boys and two men; the contemporary Gazette said two boys and two men.)
Injuries	Twenty-six burned in all; the Gazette said many of those who escaped were so badly injured their lives were in danger.
Context	During active mining (The Llangennech company's St David's Colliery between Bryn and Dafen near Llanelli, eight years after its shaft became the deepest in the South Wales coalfield.)

Late in June 1840 firedamp exploded underground at St David's Colliery near Llanelli, burning twenty-six men and boys. Five were killed, among them a boy of ten, and a sixth, David Samuel, fourteen, died of his injuries on 15 July. Survivors escaped only by retreating at once from the part of the mine where the gas fired. A newspaper said no one was to blame.

Cause

An explosion of firedamp underground; how it was ignited is not recorded in the sources read.

What happened

The Gazette reported a violent explosion of fire damp in which ten to twenty colliers escaped the same fate as the dead only by immediately retreating from the part of the mine where the ignition occurred.

Investigation & inquiry

The Gazette reported that no blame could be attributed to any party; no inquest account was found.

Recorded claims

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

There was an explosion at the mine on 27 June 1840, when twenty-six men were burned and three boys and two men killed: Henry Lewis (17), William Williams (20), Thomas John (10), William Hugh (25), Griffith Morgan (14) and David Samuel (14), who died on 15 July of his injuries. ^1,2
Welsh Coal Mines dates the explosion 27 June 1840, and the Glamorgan, Monmouth and Brecon Gazette of Saturday 11 July 1840 reports it as 'on Saturday week'. (disputed) ¹
The Durham Mining Museum lists the explosion under July 1840 and gives 6 July 1840 as the date of death of five of the dead, David Samuel dying on 15 July. (disputed) ²
The Gazette reported the immediate death of two boys and two men, ten to twenty others escaping only by immediate retreat, many so badly injured their lives were in danger, and that no blame could be attributed to anyone. ¹

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: “Late in June 1840 firedamp exploded underground at St David's Colliery near Llanelli, burning twenty-six men and boys. Five were killed,…”
Firedamp (direct cause)
Firedamp exploded underground.

Sources

(secondary) St. David's Colliery — Welsh Coal Mines
(secondary) St. David's Colliery — Durham Mining Museum

Record created: 11 September 2026 · Last researched: 13 September 2026