Cae Glas Colliery

Overview

A twice-worked drift mine at Fochriw, on the Merthyr Tydfil/Caerphilly border, driven by Guest, Keen & Nettlefolds in 1920 and worked on and off until 1997. A small family-licensed revival of the mine in the late 1950s ended in tragedy when three men, including the owner, were asphyxiated by blackdamp in September 1958 (see Disasters, below).

History

Guest, Keen & Nettlefolds drove two brick-lined drifts here in 1920, also known as the Fochriw Cross Measures Drifts, reaching the No.1 Rhondda seam via an upcast ventilation shaft sunk only 29 yards deep. The two drifts ran parallel about 400 feet below ground at their furthest extent. Work in them was short-lived: the last recorded date on the underground workings is 23 February 1924, and closure came at the same time as the nearby Fochriw Colliery (a separate, larger GKN pit at the same village, not to be confused with this mine). The workings then lay idle for over thirty years, the drift mouths blocked with brick walls roughly 100 yards in from their entrances. In 1955 the Shankland family of Fochriw, a small privately owned business, took a National Coal Board licence and reopened the south drift, working the No.3 Rhondda and Tyla Du seams. On 24 September 1958 the mine's owner and two workmen were killed by gas while checking the water level in old disused workings beyond the active faces (see Disasters, below). Coal Authority records show the mine was still working on 28 April 1992, by then owned by the Caeglas Colliery Company of Merthyr Tydfil and working the Tyla Du seam; it was licensed to Mr T.A. Rowe in 1997 and finally abandoned on 6 December 1997. Output was modest throughout its licensed years — 2,226 tons in 1960 from only 2 or 3 men — with estimated saleable reserves of 48,600 tons remaining at that date.

Geology

Reached the No.1 Rhondda seam at drift level; later working also drew on the No.3 Rhondda and Tyla Du seams of the South Wales Coalfield's Middle/Upper Coal Measures.

Workings

Two parallel brick-lined drifts (No.1 and No.2) with a 29-yard upcast ventilation shaft; after 1955 only the south drift was used.

Closure

Closed twice: first alongside Fochriw Colliery in February 1924, and finally by licensee T.A. Rowe on 6 December 1997, after 42 years as a small licensed mine.

What remains

A 2024 site visit found the roof of the workings mostly collapsed and treacherous underfoot, though surface plant — a winding engine still coupled to a tub, tubs, a compressed-air system, the mine office and store — survived in the drift and yard; the site has since been demolished.

Nearby mines

• Pant-y-Waun Colliery — 1.5 km N
• Fochriw Colliery — 1.8 km N, Caerphilly
• Dowlais Ironworks — 3.2 km W
• Albert Colliery — 3.6 km W
• Ffos-y-Fran — 3.8 km SW

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

Disasters & major incidents

• Cae Glas Colliery Gassing, 1958
  24 September 1958 · Gas / Asphyxiation · 3 fatalities
  The mine's owner and two workmen were asphyxiated by gas while checking the water level in old, disused workings beyond the active faces at this small licensed drift mine.

Recorded claims

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

• Driven by Guest, Keen & Nettlefolds in 1920 as two brick-lined drifts (the Fochriw Cross Measures Drifts) reaching the No.1 Rhondda seam via a 29-yard upcast shaft; the last recorded underground date is 23 February 1924, closing alongside Fochriw Colliery. ^1,2
• Reopened in 1955 under National Coal Board licence by the Shankland family of Fochriw, working the south drift only. ^1,2
• On 24 September 1958 the mine's owner and two workmen were asphyxiated by gas while in old disused workings beyond the active faces; both accounts agree on the date and the toll of three, though one names the cause as methane gassing and the other specifically as blackdamp encountered while checking the water level in flooded old workings. ^1,2
• Ownership passed through the Caeglas Colliery Company (Oakdale, 1967; Nelson, 1980s; Merthyr Tydfil, 1992/96) to T.A. Rowe, who closed the mine on 6 December 1997; it was still recorded working on 28 April 1992 on the Tyla Du seam. ¹
• In 1960 the mine produced 2,226 tons of coal with only 2 to 3 men employed, against estimated saleable reserves of 48,600 tons; a 1982 report records 3,022 tons from 7 men underground. ^1,3

Photographs & further reading

Sources

1. (secondary) Cae Glas — Welsh Coal Mines
2. (secondary) Small Collieries of the Tredegar area — Northern Mine Research Society
3. (observational) Report - Cae Glas Colliery - Feb 2024 — 28DaysLater

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