Trimsaran Colliery

Overview

Trimsaran, in the Gwendraeth Fawr valley between Llanelli and Kidwelly, was an anthracite and fireclay working of drift mines rather than shafts — Caedean, Waunhir and the Upper Slant, connected underground and joined on the surface by a tramway. Three haulage and firedamp accidents between 1907 and 1923 killed twenty men and boys between them, and the 1923 runaway, which took ten lives as the day shift rode out, is the one the valley remembers. The colliery closed in 1954; the ground is now Ffos Las racecourse.

History

Coal was being taken in the Trimsaran area from the 1600s, at Carway, and the Trimsaran estate — a Welsh gentry manor in the Lordship of Kidwelly — leased out the mines and coal seams under its Duchy of Lancaster land in 1606. The first major canal in south Wales was cut to carry anthracite and culm from the pits near Trimsaran down to the harbour at Kidwelly, and the oldest tramroad bridge in Wales stands just outside the village. The colliery proper appears in the Inspector of Mines list for 1896 under the Trimsaran Colliery Co. Ltd, employing 144 men on anthracite and fireclay. By the early years of the twentieth century it was three drifts: Caedean, the deepest, with an air shaft of its own; Waunhir; and the Upper Slant, known locally as the Top Colliery. The three were connected underground and by a surface tramway. Waunhir and Caedean together employed 198 in 1908 and the colliery 435 by 1918. The 1923 lists give Caedean 352 men on the Yard, Big Vein, Green and Gregog seams raising anthracite and fireclay, Waunhir 126 on the Green, Yard, Two Feet and Gregog, and the Upper Slant 63 on the Gregog alone. The village grew with it. A street of houses went up in the middle and later 1800s for the men employed at the coalmines, ironworks and brickworks, and in 1909 one of the most ornate terraces in Trimsaran was built specifically to show off what the Trimsaran Brick Company, working since about 1900, could make. Three accidents mark the record. A runaway journey of loaded tubs in the Waunhir slant killed six on 16 February 1907, and a manrider train running back down the Cadean slant killed ten on 26 April 1923 (see Disasters, below). Between them, on 22 October 1909, an explosion in the Cadean slant killed four: Owen Thomas, 30, Ted Darke, 36, and two collier's boys of sixteen, John Williams and David Sparry. By 1931 the colliery belonged to Amalgamated Anthracite Ltd and employed about 700 men. The three old drifts closed in 1934 and were replaced by the Waunffynhonnau drift, the new or Wimpey drift, which employed over 300 in 1945 and passed to the National Coal Board on nationalisation. The Board closed it in April 1954, most of the workforce going to Carway or Pentremawr. Opencast working continued on the site until 1997.

Geology

Trimsaran worked the anthracite measures at the western end of the South Wales coalfield, in the Gwendraeth Fawr valley. The seams named in the returns are the Big Vein, Green, Yard, Two Feet and Gregog, with fireclay raised alongside the coal — the raw material for the Trimsaran brickworks.

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

Workings

Three drift mines rather than shafts: Caedean, the deepest, driven 1,400 yards down the slope and served by an air shaft; Waunhir; and the Upper Slant or Top Colliery. All three were connected underground and linked on the surface by a tramway. The Cadean slant was opened in 1908 to work the Yard and Big Vein seams down from the outcrop, and by 1923 the main slant ran 1,350 yards at an average inclination of ten inches to the yard, steepening to fifteen near faults; it was nine to ten and a half feet wide and six to seven feet high, laid with T-head steel rails on wooden sleepers. Coal came to landings at the mouths of level headings by pony and went to bank on the main haulage, worked by a Robey drop-valve steam engine standing 400 yards from the drift mouth. Men rode in and out in a train of carriages known locally as a spake, hauled at a posted limit of three miles an hour against six for coal — the arrangement that failed in 1923. The three drifts were abandoned in 1934 and replaced by the Waunffynhonnau drift.

Closure

The National Coal Board closed the colliery in April 1954, most of the workforce transferring to Carway or Pentremawr. Opencast working on the site, latterly by Celtic Energy as Ffos Las, ran until 1997.

What remains

The colliery and the ironworks beside it are gone. The opencast void that replaced them has been backfilled and landscaped, and the racecourse built on it opened in 2009.

The Trimsaran weighbridge survives at the entrance to the vanished works, and the 1909 brickworks terrace still stands in the village. Outside it are the oldest tramroad bridge in Wales and the medieval Spudder's Bridge, both spanning the Gwendraeth Fawr.

Redevelopment

Ffos Las racecourse was built on the restored opencast site and opened in 2009, on ground of about 608 acres that also carried proposals for a hotel and housing.

Related mines

• Carway Colliery — Most of the Trimsaran workforce went to Carway or Pentremawr when the National Coal Board closed the colliery in April 1954.
• Pantyffynnon Colliery — Both held by Henderson's Welsh Anthracite Collieries before nationalisation.

Nearby mines

• Carway Colliery — 2.0 km N
• Pontyberem Colliery — 3.8 km NE
• Cynheidre Colliery — 4.6 km NE
• Smarts Quarry — 4.9 km NW
• Gwendraeth Colliery — 7.7 km NE

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

Disasters & major incidents

• Waunhir Slant runaway
  16 February 1907 · Haulage / Transport · 6 fatalities
  A journey of loaded tubs weighing about nine tons was being drawn up the Waunhir slant at Trimsaran when a tub tilted at the top of the brow and the hitching plate broke. The tubs ran back down the drift into the men walking out at the end of their shift, knocked out props at the bottom and brought down six yards of roof, burying eleven. Six were killed.
• Cadean Slant manrider accident
  26 April 1923 · Haulage / Transport · 10 fatalities
  A link in the second shackle of the manrider train broke as the day shift rode out of the Cadean Slant at Trimsaran, 850 yards inside the drift. The side chains meant to hold the carriages failed too, nine carriages and the tool tram ran back down the slope and crashed into the side of a heading, bringing down the roof. Ten of the 103 men aboard were killed.

Recorded claims

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

• An explosion in the Caedean slant on 22 October 1909 killed four: Owen Thomas, 30, John Williams, 16, David Sparry, 16, and Ted Darke, 36. ¹
• Welsh Coal Mines and the Trimsaran Community Council both put the colliery under Amalgamated Anthracite Ltd by 1931, employing about 700 men; the Durham Mining Museum lists the owners as the Trimsaran Colliery Co. Ltd, Welsh Anthracite Collieries Ltd and Henderson's Welsh Anthracite Collieries Ltd before the National Coal Board, without dates. The two are compatible: Amalgamated Anthracite absorbed the Welsh anthracite companies in this period. (uncertain) ^2,1,3
• At the time of the 1923 accident the Cadean slant raised about 200 tons of anthracite a day on three shifts: 110 men in the morning, 45 in the afternoon and 75 at night, the morning and night shifts drawing the coal. Approved flame safety lamps were in use, with a few electric cap lamps among the traffic men. ⁴
• J. M. Carey's report on the 1923 accident gives the main slant as 1,350 yards on that date. Welsh Coal Mines, following the contemporary newspaper account, gives 1,400 yards. (disputed) ⁴

Photographs & further reading

Sources

1. (secondary) Trimsaran Colliery — Welsh Coal Mines
2. (secondary) Trimsaran Colliery — Durham Mining Museum
3. (secondary) About Trimsaran — Trimsaran Community Council
4. (primary) Report by J. M. Carey on the accident at Cadean Slant, Trimsaran, 26 April 1923 — Northern Mine Research Society, via the Internet Archive
5. (observational) Trimsaran weighbridge, detail (Geograph 3536719) — Geograph Britain and Ireland, Richard Dorrell
6. (primary) Waunhir Trimsharan Colliery Accident, Kidwelly, 1907 — Northern Mine Research Society, via the Internet Archive
7. (secondary) Trimsaran — Wikishire
8. (secondary) Trimsaran Colliery — Northern Mine Research Society, via the Internet Archive

Record created: 11 September 2026 · Last researched: 11 September 2026