Cwmdu Colliery, Merthyr Tydfil

Overview

A Cyfarthfa Iron Works pit near Upper Abercanaid, Merthyr Tydfil, sunk in the 1820s or 1830s for coal and ironstone. It later served as the ventilation shaft for a drift and employed 200 men at its peak in 1913. It was abandoned in 1924.

History

Cwmdu Pit was sunk during the 1820s or 1830s by the Cyfarthfa Iron Works on land leased from the Dynevor Estate. With other mines around it, it worked the ironstone and coal of the Lower Coal Measures, the Garw and Five Foot, and of the Middle Coal Measures: the Bute, Upper Yard and Upper Black Pins, and later the Seven Foot, Nine Foot, Upper Six Foot and Four Foot.

In 1880 it was listed with the Cyfarthfa Collieries of Crawshay Brothers. The pit was later used to ventilate a drift mine with several entrances. In 1896 it employed 51 men underground and 5 at the surface under the manager David R. Morgan, and in 1908 151 and 15. Employment peaked at 200 in 1913. It fell to 68 in 1918 and was 101 in 1923, when it was still listed as working. It was abandoned in March 1924.

Geology

Lower and Middle Coal Measures at the north crop: the Garw, Five Foot, Bute, Upper Yard, Seven Foot, Nine Foot, Upper Six Foot and Four Foot coals, with the Upper Black Pins and other ironstones.

Workings

A pit later used as the upcast for a drift with several entrances (Cwmdu Main Drift), with an air shaft and fan to the east.

Closure

Abandoned in March 1924, the same year as the neighbouring Cwm Pit. The reason for closure is unknown.

What remains

A 2006 photograph shows the remains of an air shaft and fan that served the colliery.

Remains of an air shaft and fan at SO 0315 0519.

Redevelopment

Unknown.

Related mines

• Cwm Colliery, Merthyr Tydfil — Cyfarthfa pit planned with Cwm Pit in the same joint abandonment plans.

Recorded claims

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

• Sunk during the 1820s or 1830s by the Cyfarthfa Iron Works on land leased from the Dynevor Estate. ¹
• Peak employment was 200 men in 1913. ¹
• Abandoned in March 1924. ¹
• Its workings, with Cwmdu drift, are planned with the other Cyfarthfa pits in the Lower Two Feet Nine and Gellideg. ^2,3

Photographs & further reading

Sources

1. (secondary) Waun Wyllt Colliery — Welsh Coal Mines
2. (primary) Mine plan: Cyfarthfa, Cwm, Upcast, Glyndyrys, Pumping, Rhydycar and other pits, Gellideg — British Geological Survey
3. (primary) Mine plan: Cyfarthfa, Cwm, Upcast, Glyndyrys, Pumping, Rhydycar, Cwmdu and other pits, Lower 2'9" — British Geological Survey

Record created: 2 October 2026 · Last researched: 2 October 2026