Yniscedwyn Colliery

Overview

Yniscedwyn was opened in 1872 by the Yniscedwyn Iron Company at Ystradgynlais, on ground where ironmaking had gone on commercially since before 1720. Until 1892 the mine was entered by a shaft 90 yards deep; water drove it to pumping only, and a drift was driven instead, dipping 1 in 3 for 300 yards, for men, supplies and coal. In August that year nine men waiting to ride down that drift were sent hurtling into the mine when someone pulled the stop block. It passed through a long line of owners into Amalgamated Anthracite, employed 618 people in 1913, and was closed by the Coal Board on 22 March 1968.

History

Ironmaking on a commercial scale had started around Ystradgynlais before 1720, when Crowley and Company opened an ironworks at Yniscedwyn; by 1780 Parsons owned a forge at Ystalyfera, joined in 1837 by Treacher and James, and in 1838 Budd and Company bought and merged the concerns. The colliery itself was opened in 1872 by the Yniscedwyn Iron Company, an anthracite mine served by the Swansea Vale line, flanked by Onllwyn to the east, Gwaunclawdd to the north and Ystradgynlais to the south. Until 1892 the mine was reached by a shaft 90 yards deep. Water in the shaft turned it over to pumping alone, and a new drift was driven at a dip of 1 in 3 for 300 yards to carry men, supplies and coal; the winding drums for both shaft and drift were coupled to the same steam engine. On 24 August 1892 nine men sat in manriding trams at the mouth of that drift when one of them, for reasons never established, removed the stop block. The trams ran away into the mine, struck the roof and brought it down (see Disasters, below). The colliery passed through more owners than most: the Yniscedwyn Colliery Company in 1893, the Ystradgynlais Colliery Company by 1896 with 225 people under Owen Powell, the South Wales Anthracite Colliery Company of Swansea from about 1900, employing 618 by 1913, and the Yniscedwyn Anthracite Company from 1917. In 1923 Alfred Mond's Amalgamated Anthracite Collieries absorbed it along with the Gurnos company; by 1935 that combine ran 26 anthracite collieries employing 13,779 people, 600 of them here. In 1901 the mine was described working the Big and Brass veins by pillar and stall, safety lamps in the Big and naked lights in the Brass, ventilated by a Guibal fan twenty feet across.

Geology

Yniscedwyn worked the anthracite of the northern outcrop of the South Wales coalfield in thin and awkward seams. The Middle Vein, probably the Lower Five Feet, ran between 0.71 and 0.81 metres; the Six Feet was 36 inches, the Red Vein 48, the Gellideg 21, and the Brass — the Bute seam — 36 inches. The Big Vein, the Nine Feet, was extensively worked and became abnormally thick in places, swelling from 11 feet to as much as 70. The Black Vein, found in 1950 with a section of 33 inches, was reckoned to hold seven million tons on its own.

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

Workings

A shaft 90 yards deep until 1892, then kept for pumping while a drift dipping 1 in 3 for 300 yards carried men, supplies and coal, both wound by the same steam engine. The upcast was 16 feet by 12 and 300 feet deep, ventilated by a Guibal fan twenty feet across and seven feet six wide. Working was pillar and stall in 1901. Coal was hand-filled by shovel onto face conveyors as late as 1947, when output per man-shift was only ten hundredweight; from 1950 coal cutters and face conveyors went into the Black Vein, a new drift was driven from the surface, compressed-air machinery was replaced with electric, trunk conveyors replaced the haulage and new baths were built.

Closure

The National Coal Board spent £170,000 on the colliery in 1961-62 and lifted output from 700 to 1,000 tons a day. In 1965 it was close to closure, the Board saying it was not closing the pit — the men were — and citing absenteeism of up to 37 per cent; the union appealed, output per man-shift rose to 25 hundredweight by July, and closure was deferred. Yniscedwyn was closed by the Board on 22 March 1968, abandoning the Black Vein.

What remains

The colliery has been cleared. The fan house survives above the site — the top of a shaft drawing air from the mine — on the hillside at Ystradgynlais.

Nearby mines

• Seven Sisters Colliery — 1.8 km E, Neath Port Talbot
• Pwllbach Colliery — 3.2 km SW, Neath Port Talbot
• Blaenant Colliery — 4.5 km SE, Neath Port Talbot
• Crynant Colliery — 4.9 km S, Neath Port Talbot
• Onllwyn Colliery — 4.9 km E, Neath Port Talbot

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

Recorded claims

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

• The colliery was opened in 1872 by the Yniscedwyn Iron Company, on ground where Crowley and Company had opened an ironworks before 1720. ¹
• Until 1892 access was by a shaft 90 yards deep; water problems turned it over to pumping alone and a new drift was opened at a dip of 1 in 3 for 300 yards for men, supplies and raising coal, both wound by the same steam engine. ¹
• The Northern Mine Research Society names six men killed in the 1892 runaway and three injured; the Durham Mining Museum's disaster listing gives seven lives lost. (disputed) ^1,2
• The Nine Feet seam, called the Big Vein here, was extensively worked and became abnormally thick in places, increasing from 11 feet to 70 feet. ¹
• Amalgamated Anthracite Collieries, formed in 1923 by Alfred Mond, absorbed the Yniscedwyn company; by 1935 the combine ran 26 anthracite collieries employing 13,779 people, 600 of them at Yniscedwyn. ¹
• The colliery was close to closing in 1965 over absenteeism of up to 37 per cent, won a reprieve when output per man-shift rose to 25 hundredweight, and was closed by the National Coal Board on 22 March 1968. ¹

Photographs & further reading

Sources

1. (secondary) Yniscedwyn Colliery — Northern Mine Research Society (read via an August 2024 Wayback Machine capture)
2. (primary) Durham Mining Museum: Yniscedwyn Colliery — Durham Mining Museum, from the Lists of Mines
3. (observational) Ynysgedwyn Fan House (photographed 2015) — Geograph Britain and Ireland, Nigel Davies

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