Lletty Shenkin Colliery explosion, 1853

On 15 September 1853 firedamp exploded in Level No. 1 of Lletty Shenkin Colliery at Cwmbach, near Aberdare, while 49 men and boys were at work. Two door boys, David Thomas, 11, and John Williams, 12, were killed and the collier William Rees died of his burns. A coroner's jury found the manager, David Sims, guilty of manslaughter, but he was acquitted at the Assizes.

Cause

Firedamp in the workings was fired at a naked light. The coroner heard that William Rees had worked a pillar with a naked light in a pit that needed locked safety lamps.

Contributing factors

The inspector, Herbert Mackworth, had warned the manager after an earlier explosion that the lamps must always be locked and the goaf better sealed off from the workings, because gas could be seen escaping from it. A ventilation door had been left open; the prosecution held that this was negligence, though it let the afterdamp clear and saved lives.

What happened

The pit had been raising coal since April 1846 and had already had several explosions that killed one man at a time. On the morning of the explosion 39 men and 10 boys were below. The blast in Level No. 1 killed the two door boys, one by a fractured skull from the rush of air, and burned many of the men; Rees died some days later.

Investigation & inquiry

Inquests were held before George Overton, coroner, at the Black Lion, Aberdare, on 28 September, and later at the Boot Inn on Rees. Mackworth produced his earlier letter of warning. The jury found manslaughter against David Sims, the principal manager and a trustee of the colliery.

Legal & regulatory aftermath

Sims was indicted at the Glamorganshire Spring Assizes in March 1854 for the manslaughter of David Thomas, with William Grove QC prosecuting. The judge advised that the evidence was not enough to convict, and the jury acquitted him. Prosecuting counsel regretted that the new inspection act made owners and managers answerable for nothing beyond reporting an accident.

What's uncertain

Points where sources disagree or the record could not be settled; both accounts are kept. All open questions in the archive.

• The explosion was on Thursday 15 September 1853. (disputed) ^2,3
• The explosion was on 15 November 1853. (disputed) ¹

Recorded claims

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

• An explosion of firedamp at Lletty Shenkin Colliery, Cwmbach, killed two boys outright and fatally burned a collier; about fifteen others were hurt. ^1,2,3
• The explosion was on Thursday 15 September 1853. (disputed) ^2,3
• The explosion was on 15 November 1853. (disputed) ¹
• A collier, William Rees, had worked a pillar with a naked light where only a locked safety lamp should have been used. ²
• The coroner's jury returned a verdict of manslaughter against David Sims, the principal manager. ^2,3
• At the Glamorganshire Spring Assizes in March 1854 Sims was tried for the manslaughter of David Thomas and acquitted. ^1,3

Related terminology

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

• Afterdamp (contextual relationship)
  Named in this record’s contributing factors: “…the prosecution held that this was negligence, though it let the afterdamp clear and saved lives.”
• Firedamp (contextual relationship)
  Named twice in this record, first in the summary: “On 15 September 1853 firedamp exploded in Level No. 1 of Lletty Shenkin Colliery at Cwmbach, near…”
• Goaf (contextual relationship)
  Named in this record’s contributing factors: “…an earlier explosion that the lamps must always be locked and the goaf better sealed off from the workings, because gas could be seen…”
• Naked Light (contextual relationship)
  Named twice in this record, first in the cause: “Firedamp in the workings was fired at a naked light. The coroner heard that William Rees had worked a pillar with a…”
• Safety Lamp (contextual relationship)
  Named in this record’s cause: “…had worked a pillar with a naked light in a pit that needed locked safety lamps.”

Sources

1. (secondary) NMRS: Letty Shenklin Explosion, Aberdare, 1853 — Northern Mine Research Society
2. (primary) The Cardiff and Merthyr Guardian, 15 October 1853: The late explosion at Lletty Shenkin coal works — Welsh Newspapers Online (National Library of Wales)
3. (primary) The Cardiff and Merthyr Guardian, 18 March 1854: Glamorganshire Spring Assizes, the explosion at Lletty Shenkin — Welsh Newspapers Online (National Library of Wales)

Record created: 11 October 2026 · Last researched: 11 October 2026