Glynhebog Colliery

Overview

A Pontyberem anthracite slant of 1892 whose coal was over 98 per cent carbon, notorious for dust disease, merged with Pontyberem in 1926 and later reused as Cynheidre's No. 3 slant until 1989.

History

Glynhebog (or Clynhebog) Slant was opened near Pontyberem in the Gwendraeth Valley by the Pontyberem Collieries Co. Ltd in 1892 and was connected to the nearby Coalbrook colliery. Its anthracite was of the very highest quality, over 98 per cent carbon, from the Triquart, Big Vein, Pumpquart, Gwendraeth and Grass seams.

It employed only 74 in 1896. In May 1900 a roof fall at a pillar being extracted in the Pumpquart released gas that fired at the naked lights of men waiting nearby, and two died. By 1918 the Ammanford Colliery Co. Ltd had it, with 397 men, and in 1923 it employed 564 in the Lower Pumpquart and Triquart seams.

Glynhebog had little of the outbursts of coal and gas that plagued its neighbours, but the dry, dusty anthracite and poor ventilation killed many of its miners in their twenties from dust disease, without compensation; a ventilation shaft sunk a mile away did little good. Amalgamated Anthracite Collieries merged it with Pontyberem colliery in 1926, and the combined Glynhebog, Pontyberem and Great Mountain No. 3 employed 335 in 1945. In the early 1950s the National Coal Board renamed the drift Cynheidre No. 3 slant and used it to develop Cynheidre's roadways; it stayed open until Cynheidre closed in 1989.

Geology

Gwendraeth Valley anthracite of over 98 per cent carbon, from the Triquart, Big Vein, Pumpquart, Gwendraeth and Grass seams; the Lower Pumpquart and Triquart in 1923. Good roof conditions and dry, dusty coal.

Workings

A slant (drift), connected to Coalbrook colliery, with a ventilation shaft sunk about a mile away that later became the third shaft of the Cynheidre complex.

Closure

Merged with Pontyberem colliery in 1926. The drift was renamed Cynheidre No. 3 slant in the early 1950s and stayed open until Cynheidre closed in 1989.

What remains

Unknown.

Redevelopment

Unknown.

Related mines

• Cynheidre Colliery — The NCB renamed Glynhebog drift Cynheidre No. 3 slant in the early 1950s and used it to develop Cynheidre's roadways; Glynhebog's ventilation shaft became Cynheidre's third shaft.
• Pontyberem Colliery — Merged in 1926 under Amalgamated Anthracite Collieries; by 1945 the two were worked together with Great Mountain No. 3.

Recorded claims

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

• Glynhebog was opened by the Pontyberem Collieries Co. Ltd in 1892. ^1,2
• Its anthracite was over 98 per cent carbon. ¹
• On 28 May 1900 a roof fall released gas that fired at naked lights in the Pumpquart; two men died. ^3,2
• It employed 74 in 1896, 397 in 1918 and 564 in 1923. ¹
• It was merged with Pontyberem colliery in 1926. ¹
• The drift became Cynheidre No. 3 slant and stayed open until 1989. ¹
• BGS holds a Glynhebog plan filed under Pontyberem, reflecting the two collieries' merger. ⁴

Photographs & further reading

Sources

1. (secondary) Welsh Coal Mines: Glynhebog — Welsh Coal Mines
2. (secondary) NMRS Coal Mining Accidents and Deaths: David Rees, Glynhebog, Pontyberem, 28 May 1900 — Northern Mine Research Society
3. (secondary) Fatalities 1900 — Welsh Coal Mines
4. (primary) BGS / Mining Remediation Authority mine plan: GLYNHEBOG [PONTYBEREM] — British Geological Survey

Record created: 10 October 2026 · Last researched: 10 October 2026