Birchrock Colliery

Overview

A drift colliery in the Cwmdulais valley three miles above Pontarddulais, opened as Birch Rock about 1868 on land leased by John Glasbrook and known from 1904 as Graig Merthyr, locally 'Cory'. It worked the low-ash Graigola seam for Swansea's patent-fuel trade, grew to over a thousand men by 1920 with Cefn Drim, and lost seven men in two accidents in October 1909. Nationalised in 1947, it closed on 23 June 1978 with its reserves exhausted, its men moving to the new Betws mine.

History

By December 1867 John Glasbrook had leased 800 acres in the Cwmdulais valley and built a railway to join the Llanelly and Swansea Extension Railway. The NMRS dates the opening of Birch Rock to 1868, while National Coal Board records gave 1873 and the Inspector's report on the 1909 explosion 1869; on 4 November 1869 a collier, Thomas Thomas, was killed by runaway trams under the Birch Rock Colliery Company. In 1870 the local Board of Health was discussing the effect of the mining on the Blaennant Ddu reservoir, and in 1871 the Graigola vein was advertised to let, 700 acres with the pits sunk to half their depth. The Birch Rock Coal Company worked a Lower and an Upper Level in 1878. Welsh Coal Mines has the mine unlisted in 1881 and abandoned in 1882; the NMRS has it worked in 1882-84 by Cory, Yeo and Company with the neighbouring Graigola Colliery. In 1885 the Graigola Merthyr Company Ltd was registered to take over Cory, Yeo and Co. and the Compagnie Houillère de Graigola Merthyr, and the mine was listed again from 1886. It stood idle from June 1892 to 1894, and in 1896 employed 88 men under Owen Morgan. From 1903 it was listed as 'Birch Rock or Graig Merthyr', and from 1904 simply as Graig Merthyr. Manpower rose from 130 in 1899 to 801 in 1908. On 1 October 1909 an explosion of gas as the night shift was about to leave killed five, and on 21 October a fall of stone in a heading killed two more (see Disasters, below). The company advertised its Graigola Merthyr patent fuel, 600,000 to 700,000 tons a year made at King's Dock, Swansea, and the pit reached a peak of 1,177 men with Cefn Drim in 1920. D. R. Llewellyn chaired the company in 1935, with Viscountess Rhondda on the board, when the colliery employed 685. Nationalised in 1947, it had its own washery and in 1961 was grouped with Felinfran, Clydach Merthyr and Daren. Graig Merthyr, worked only in the Graigola seam until 1958, later took the Swansea Six Feet and Three Feet, the last of which was abandoned when the colliery closed on 23 June 1978, its reserves exhausted; most of its men went to the newly opened Betws mine.

Geology

Worked the Graigola seam, the Swansea Three Feet, easily reached near its outcrop and one of the lowest-ash coals in the coalfield; its lower leaf averaged about 32 inches. From 1959 the Swansea Six Feet and Three Feet were also worked: the Six Feet lower bed was abandoned on 16 May 1964, the upper bed on 19 February 1965, the Six Feet on 21 December 1977 and the Three Feet on 23 June 1978.

Geological setting: Sedimentary Beds and Seams (well documented example)

Workings

A spread of levels and slants: the Lower and Upper Birchrock levels (1878), the Birchrock level with an 80-foot upcast (1891), and later the Twyn Tyle slant, Graig Merthyr North Slant, East Main slants and return, and the Lliw slants; Welsh Coal Mines notes that how the openings developed is far from clear. The colliery had its own coal preparation plant under the National Coal Board.

Closure

Closed on 23 June 1978 through exhaustion of its coal reserves; most of the workforce transferred to the newly opened Betws mine.

What remains

A 2014 photograph shows the road from Pant-y-ffa that led down into Cwmdulais and to the former colliery. No report of surviving colliery remains has been found.

Nearby mines

• Brynlliw Colliery — 6.1 km SW
• Morlais Colliery — 7.1 km SW, Carmarthenshire
• Pantyffynnon Colliery — 7.3 km N, Carmarthenshire
• Garngoch Colliery — 7.4 km S
• Mynydd Newydd Colliery — 7.7 km S

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

Disasters & major incidents

• Graig Merthyr Colliery explosion, 1909
  1 October 1909 · Explosion · 5 fatalities
  In the early hours of Friday 1 October 1909, as the night shift at Graig Merthyr Colliery in the Cwmdulais valley was about to leave, a pocket of gas exploded and killed five colliers and injured another. An open lamp was found at the face, and the Inspector thought the gas might have gathered in small coal lying on the floor, but he could offer no firm explanation. Three weeks later a fall of stone at the same colliery killed two more men.

Recorded claims

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

• By December 1867 John Glasbrook had leased 800 acres and built a railway to connect with the Llanelly and Swansea Extension Railway. ¹
• Birchrock was opened in 1868. (disputed) ²
• National Coal Board records gave 1873 for the opening and the Inspector's report on the 1909 explosion gave 1869. (disputed) ²
• Welsh Coal Mines has the mine unlisted in 1881 and abandoned in 1882, reappearing from 1886; the NMRS has Cory, Yeo and Company working it with Graigola in 1882 and 1884. (disputed) ^1,2
• Listed as 'Birch Rock or Graig Merthyr' from 1903 and as Graig Merthyr from 1904, owned by the Graigola Merthyr Co. Ltd until nationalisation. ^1,2
• The colliery worked the lower leaf of the Graigola seam, about 32 inches thick and among the lowest in ash in the coalfield, alone until 1958. ^1,2
• On 1 October 1909 an explosion killed Arthur Schroeder, Edward Mandry, John Whelan, David Rees and Samuel Jones; on 21 October a fall of stone killed Thomas Rees and Griffith Jeffreys. ^1,2
• Graig Merthyr closed on 23 June 1978, its reserves exhausted, and most of its men transferred to the new Betws mine. ^1,2

Photographs & further reading

Sources

1. (secondary) Birchrock Colliery (Graig Merthyr) — Welsh Coal Mines
2. (secondary) Graig Merthyr Colliery — Northern Mine Research Society (information supplied by Ray Lawrence)

Record created: 13 September 2026 · Last researched: 14 September 2026