Ynys Dafydd Colliery

Overview

One of five collieries of the Governor and Company of Copper Miners' Cwm Avon Works, named after the farm it was sunk on and claimed as the first pit sunk in the area. A firedamp explosion in the Big Vein (Nine-Feet seam) killed twelve men and boys here on 24 May 1856 (see Disasters, below).

History

Ynys Dafydd — also spelled Ynisdavid — was named after the farm on which it was sunk, and was claimed to be the first pit sunk in this part of the Afan Valley. It was owned by the Governor and Company of Copper Miners in England, proprietors of the whole of the extensive Cwm Avon Works, of which it was one of five collieries; it was also known as No.43 pit and formed part of the wider Oakwood Colliery grouping. The pit was possibly deepened, or first sunk, in 1844, reaching a depth of 231 feet. On 24 May 1856 a firedamp explosion in the Big Vein (the Nine-Feet seam) killed twelve men and boys (see Disasters, below). Ynys Dafydd was abandoned in 1872.

Geology

Worked the Big Vein, also called the Nine-Feet seam, of the South Wales Coalfield.

Workings

A single pit (No.43) reaching the Big Vein (Nine-Feet seam) at 231 feet, one of five Cwm Avon Works collieries.

Closure

Abandoned in 1872; no cause of closure is given in the sources.

What remains

Unknown.

Related mines

• Wern Colliery, Cwmafan — Both were coal levels of the same Cwm Avon Works, owned throughout by the Governor and Company of Copper Miners in England.

Nearby mines

• Wern Colliery, Cwmafan — 0.9 km SE
• Eaglesbush Colliery — 1.0 km NW
• Cwrt Herbert Colliery — 2.7 km NW
• Cwmgwineu Colliery — 3.7 km SE
• Cwmavon Copper Works — 4.0 km SE

Straight-line distance, within 15 km. Show on the map.

Disasters & major incidents

• Ynisdavid Colliery Explosion, Cwmavon, 1856
  24 May 1856 · Explosion · 12 fatalities
  A firedamp explosion in the Big Vein, deep in the workings, killed nine men and three boys; the colliery's own agent led the rescue and recovery, recorded in detailed inquest testimony.

Recorded claims

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

• Named after the farm it was sunk on, claimed as the first pit in the area, and possibly deepened or first sunk in 1844 to 231 feet; owned by the Governor and Company of Copper Miners in England as one of five Cwm Avon Works collieries, also known as No.43 pit and part of the Oakwood Colliery grouping. ¹
• A firedamp explosion in the Big Vein (Nine-Feet seam) on 24 May 1856 killed twelve men and boys. ^1,2
• Abandoned in 1872. ¹

Photographs & further reading

Sources

1. (secondary) Small Collieries in the Afan Valley and surrounding areas — Northern Mine Research Society
2. (secondary) Ynisdavid Colliery Explosion — Cwmavon — 1856 — Northern Mine Research Society

Record created: 14 September 2026 · Last researched: 15 September 2026