Pentremawr Colliery

Overview

A group of anthracite slants at Pontyberem in the Gwendraeth valley, the Capel Ifan slants, opened by the Pentremawr Colliery Company about 1870 and worked for a century; it employed over a thousand in the 1920s and 1930s, suffered violent outbursts of gas and coal, and was merged with Cynheidre in 1974.

History

Pentremawr Colliery, also called Capel Ifan, lay near Pontyberem in the Gwendraeth valley, about eight miles south-east of Carmarthen, where the anthracite seams come close to the surface at the western end of the coalfield. Because of the dip and depth of the coal it was worked by slants rather than shafts. An older Pentremawr had existed before 1840. The Pentremawr Colliery Company of Pontyberem drove its first two slants in 1870 but abandoned them when they struck a great fault; the slants that followed were named Capel Ifan Nos. 1, 2 and 3, working the Gwendraeth, Braslyd, Gras and Triquart seams, and a fourth slant was driven to the Pumpquart in 1913.

The colliery employed 160 men in 1896, when its chief mechanic, Jones Jones, is credited with inventing the Pontyberem safety lamp, and 643 by 1910. Employment passed a thousand in the mid-1920s. The company was absorbed into United Anthracite Collieries in 1926 and Amalgamated Anthracite Collieries in 1927. Pithead baths were opened in March 1939, and the same year work on the fault led to the eight-foot Big Vein. On 3 July 1945 an outburst of gas and 600 tons of coal killed two miners.

At nationalisation in 1947 it employed 718 and raised about 200,000 tons, and in 1956 900 men produced 226,273 tons. On 1 September 1966 the Big Vein threw out some 1,000 tons of coal dust in what is described as the largest outburst of methane and fine coal in the country, without loss of life. The colliery was linked underground with the new Cynheidre Colliery in the mid-1960s; the Pumpquart No. 4 slant closed in 1968, and the rest was merged into Cynheidre on 31 March 1974.

Geology

Anthracite of the western coalfield, worked in the Gwendraeth (Yard), Braslyd, Gras, Triquart, Pumpquart, Big or Hwch and Big Vein seams; a major fault cut off the first slants, and the Big Vein was prone to outbursts of firedamp and coal.

Workings

Slants rather than shafts: Capel Ifan Nos. 1-3, the Pumpquart No. 4 slant of 1913, and later Pentremawr Nos. 1-5 slants; a washery and central workshop.

Closure

The Pumpquart No. 4 slant closed in 1968; the rest of the colliery was merged with Cynheidre on 31 March 1974, and Cynheidre closed in 1989.

What remains

Several colliery buildings and a couple of capped shafts were still on the site in 2010; a proposal of 2009 to work it opencast met local opposition.

Buildings scattered about the site, capped shafts and a blocked slant (2010).

Related mines

• Cynheidre Colliery — Physical link: Pentremawr was linked underground with Cynheidre in the mid-1960s and merged into it in 1974.

Disasters & major incidents

• Cynheidre-Pentremawr outburst, 1971
  6 April 1971 · Gas / Asphyxiation · 6 fatalities
  Shortly after noon on 6 April 1971, a heading being driven in the No. 2 Cross Measure Driveage at Cynheidre erupted without warning, ejecting around 400 tons of fine coal and roughly two million cubic feet of firedamp into the workings. Six men were killed by asphyxiation, and the gas travelled far enough through the ventilation system to overcome dozens more at a longwall face a considerable distance away before a quick-thinking electrician shut down an auxiliary fan and slowed its spread.

Recorded claims

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

• The Pentremawr Colliery Company opened its first slants at Capel Ifan about 1870, abandoning two at a fault before the Capel Ifan slants were driven. ^1,2,3
• The colliery's chief mechanic, Jones Jones, is credited with inventing the Pontyberem safety lamp. ¹
• Pentremawr Colliery employed 1,042 people in 1933. ^4,2
• BGS plans of Pentremawr (Capel Ifan) cover the Braslyd, Gwendraeth, Gras and Pumpquart seams. ⁵
• On 1 September 1966 about 1,000 tons of coal dust burst from the Big Vein at Pentremawr without loss of life. ¹
• The Pumpquart No. 4 slant closed in 1968 and the rest of Pentremawr was integrated with Cynheidre on 31 March 1974. ^1,2
• In 2010 several buildings, a couple of capped shafts and a blocked slant remained on the Capel Ifan site. ⁶

Photographs & further reading

Sources

1. (secondary) Pentremawr Colliery — Wikipedia
2. (secondary) Pentremawr Colliery (NMRS South Wales collieries) — Northern Mine Research Society
3. (secondary) Capel Ifan Colliery; Pentremawr Colliery, Coflein NPRN 421058 — Coflein (RCAHMW)
4. (primary) Pentremawr Colliery (Capel Ifan Colliery) — Durham Mining Museum
5. (primary) BGS / Mining Remediation Authority mine plan 21864540: Pentremawr (Capel Ifan), Braslyd, Gwendraeth, Gras, Pumpquart — British Geological Survey
6. (observational) Capel Ifan/ Pentremawr Colliery (Derelict Places, 2010) — Derelict Places

Record created: 23 October 2026 · Last researched: 23 October 2026