Great Mountain Colliery

History

The Great Mountain Colliery Company drove its Nos. 1 and 2 slants, the intake and return drifts, into the Green Vein at Tumble in the Gwendraeth Valley in 1887, and the mine grew into the largest and most productive in the valley, raising 2,000 tons of anthracite a week with 700 men by 1892. Its drifts were among the longest and deepest in the valley, and it worked seven seams, the Big Vein by pillar and stall and the Green Vein by longwall and later the Braslyd, Gras, Stanllyd, Triquart and Pumpquart, ventilated by a 20-foot Waddle fan and served by the Llanelly and Mynydd Mawr Railway. In September 1893, during a bitter strike, the owners brought in strikebreakers from Scotland and England; strikers wrecked their lodgings and the manager's house, which they tried to blow up with gunpowder, and the Inniskilling Dragoons were sent to escort the strikebreakers away. Owned by John Waddell and Sons in 1890 and by the Great Mountain Anthracite Collieries Company in 1896, it employed 842 men by 1913. In 1924 it was bought with the Ammanford Colliery Company for £500,000 by United Anthracite Collieries, which merged into Amalgamated Anthracite Collieries in 1926; the 1924 prospectus credited Great Mountain with more than half of a combined output of 435,000 tons a year. A No.3 Pit, an upcast shaft 18 feet across and 600 yards deep, was sunk in 1939-41. The mine was plagued by sudden outbursts of fine coal and methane, 37 of them between 1913 and 1959: two men died in one on 31 October 1935 and three on 25 February 1958 (see Disasters, below). A union survey of 1948-61 found that 40 per cent of its men had pneumoconiosis to some degree, and in January 1948 the collier William King set an anthracite-region record by filling 71 tons in a week from a 30-inch seam by pick and shovel. Nationalised in 1947 with over 900 men, it closed on 5 May 1962 and its men moved to the new Cynheidre colliery; the No.1 slant was kept to pump water for Cynheidre until 1986, and the No.3 Pit became Cynheidre's upcast shaft.

Geology

Anthracite of the western South Wales coalfield: the Big, Green, Braslyd, Gras, Stanllyd, Triquart and Pumpquart seams, prone to outbursts of coal and methane; the Big Vein varied from nine feet to under three feet along a single face.

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

Workings

Slants (drifts) rather than shafts: Nos. 1 and 2, intake and return, driven into the Green Vein in 1887, two more opened in 1906, with man-riding at 6 mph; the No.3 Pit, an upcast shaft 18 feet in diameter and 600 yards deep, sunk 1939-41. Waddle fans (20 ft, and a new 7 ft 6 in fan in 1951), its own washery and a central power station.

Closure

The slants closed on 5 May 1962 (NMRS; Welsh Coal Mines and Coflein give 1962) and the men were transferred to Cynheidre. The No.1 slant stayed open to pump water for Cynheidre until 1986, and the No.3 Pit, deepened in 1955, became Cynheidre's upcast shaft.

Related mines

• Cynheidre Colliery — Great Mountain's No.3 Pit became Cynheidre's upcast shaft and its No.1 slant pumped water for Cynheidre until 1986; its men transferred there in 1962.
• New Dynant Colliery — Owned by the Great Mountain company in 1923; the BGS plans record New Dynant as Great Mountain No. 3.

Disasters & major incidents

• Great Mountain Colliery roof fall, 1890
  27 November 1890 · Collapse / Roof Fall · 2 fatalities

  On 27 November 1890 two colliers were killed by a fall of roof at Great Mountain Colliery, at Tumble in Carmarthenshire.

  Morgan Davies, aged 31, a collier, was among two men killed when a fall of roof about fifteen feet by four came down from a slip parallel to the longwall face. The other was Isaac Lloyd. It was a Thursday; the fall came on them suddenly as they worked and killed them at once. Each was married with three children.

• Great Mountain Colliery gas accident, 1925
  27 April 1925 · Gas / Asphyxiation · 2 fatalities
  A fireman at Great Mountain Colliery, Tumble, was overcome by gas on 27 April 1925, and a second fireman who went in to rescue him was suffocated too.
• Great Mountain Colliery outburst, 1935
  31 October 1935 · Gas / Asphyxiation · 2 fatalities

  An outburst of fine coal and methane at Great Mountain Colliery, Tumble, on 31 October 1935 killed two miners, Edgar Owen Collins and Llewellyn Evans: the first of the pit's two fatal outbursts among 37 recorded between 1913 and 1959.

  Great Mountain was troubled throughout its life by outbursts, in which fine coal and gas erupt suddenly into the face. On 31 October 1935 one killed two miners.

• Great Mountain Colliery outburst, 1958
  25 February 1958 · Gas / Asphyxiation · 3 fatalities
  A sudden outburst of coal at Great Mountain Colliery, Tumble, on the evening of 25 February 1958 killed three men; two escaped. The pit suffered 37 outbursts of fine coal and methane between 1913 and 1959, and the accident was raised in the Commons two days later.

Culture

• The Tumble riots, 1893 (Labour)
  The riots broke out when this colliery's owners imported strikebreakers during the 1893 strike.
• Tumble RFC and the Great Mountain Colliery (Sports)
  Tumble RFC was formed in 1897 to give recreation to the workers of this colliery.

Recorded claims

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

• Work began on the No.1 intake and return drifts in 1887 with the formation of the Great Mountain Colliery Company Ltd; by 1892 the mine produced 2,000 tons a week with 700 men. ^1,2
• In September 1893 the owners imported strikebreaking miners from Scotland and England; strikers attacked their lodgings and the manager's house, which they tried to blow up with gunpowder, and the Inniskilling Dragoons were brought in. ¹
• Owned by John Waddell and Sons in 1890 and the Great Mountain Anthracite Collieries Company in 1896, it was bought in 1924 by United Anthracite Collieries, which merged with Amalgamated Anthracite Collieries in 1926. ¹
• Between 1913 and 1959 the mine suffered 37 outbursts of fine coal and methane; Edgar Owen Collins and Llewellyn Evans died in one on 31 October 1935, and Kenneth Melville Jenkins, William Glyn Jones and Ieuan Lewis in one on 25 February 1958. ^1,2
• The Great Mountain Colliery closed in 1962; the No.1 drift stayed open for years afterwards as a pumping station. ^1,2,3

Photographs & further reading

Sources

1. (secondary) Great Mountain Colliery — Northern Mine Research Society
2. (secondary) Great Mountain Colliery — Welsh Coal Mines
3. (secondary) Great Mountain Colliery, Tumble (NPRN 421100) — Coflein (RCAHMW)
4. (primary) Great Mountain Tip No 33 (Mining Remediation Authority plan, via BGS catalogue item 21835250) — British Geological Survey / Mining Remediation Authority
5. (primary) Tumble Colliery, Carmarthenshire (Accident), HC Deb 27 February 1958 vol 583 cc547-8 — Hansard

Record created: 19 September 2026 · Last researched: 19 September 2026