Lluest Colliery Explosion, 1899

An explosion at Lluest Colliery at Pontyrhyl in the Garw Valley on 18 August 1899 killed nineteen men and boys. One of the dead had come from another part of the mine to help and was overcome by afterdamp. A Home Office report on the disaster was laid before the Commons that October. The colliery stopped producing three years later.

Cause

Not established from the sources read.

What happened

The explosion came on 18 August 1899 at the Lluest colliery at Pontyrhyl, a house-coal pit working the No. 3 Rhondda seam in a section as little as twenty-two inches thick. Nineteen men and boys were killed. One of them had not been caught in the blast at all. William Thomas, known as Tydu, left another part of the mine to attempt a rescue of the stricken men and was overcome by afterdamp. Production at the colliery ceased in 1902.

Investigation & inquiry

A Home Office report about the explosion was made to the House of Commons in October 1899. That report, and a separate official report on the explosion, are held by the Garw Valley Heritage Society; neither has been read for this record.

Memorials & commemoration

A memorial in the valley commemorates the miners who died at the Garw collieries.

Recorded claims

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

• Nineteen men and boys were killed. (medium) ¹
• One of the victims, William Thomas of Tydu, was overcome by afterdamp after leaving another part of the mine to attempt a rescue of the stricken men. (medium) ¹
• A Home Office report about the explosion was made to the House of Commons in October 1899, and an official report on the explosion survives; both are held by the Garw Valley Heritage Society. (high) ²

Related terminology

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

• Afterdamp (contextual relationship)
  Named twice in this record, first in the summary: “…had come from another part of the mine to help and was overcome by afterdamp. A Home Office report on the disaster was laid before the Commons…”
• Colliery (contextual relationship)
  Named 4 times in this record, first in the summary: “An explosion at Lluest Colliery at Pontyrhyl in the Garw Valley on 18 August 1899 killed nineteen…”

Sources

1. (secondary) Llest Colliery, Pontyrhyl — Welsh Coal Mines
2. (secondary) Garw Valley Heritage Society: archive catalogue — Garw Valley Heritage Society

Record created: 3 September 2026 · Last researched: 3 September 2026