Cwmbran Colliery

Overview

A colliery at Upper Cwmbran whose main adit was driven 2,080 yards through the Old Red Sandstone, the Main Limestone and the Millstone Grit before it even reached the coal — the largest winning of coal by adit in South Wales. It stopped in 1927.

History

A colliery at Cwmbran is shown on Charles Halsall's Mineral and Agricultural Map of 1811. In the late 1830s two levels, the Porthmawr Nos. 1 and 2, were driven into the eastern slopes of Mynydd Maen at Upper Cwmbran to work the outcropping seams of the Gwent coal basin; No. 2 mainly produced clay and was known as the Fire Clay Level. The owner was Reginald J. Blewitt of Llantarnam Abbey, member for the Monmouth Boroughs, and in December 1837 the first coal went by tramroad to a new wharf at Caerleon. Blewitt shipped cargoes to London and advertised the coal in the metropolitan papers as similar in quality to Tredegar.

In 1843 the colliers struck against a reduction of fivepence a ton, and several were sentenced to a month's hard labour for breaching their contracts of employment.

John Lawrence bought the colliery in 1852 and opened the Mine Slope in 1854; ventilation was by a mechanical fan drawing foul air out through the entrance, with fresh air coming down an airshaft further up the mountain. No. 1 closed in 1865. On 26 April 1866 three men were scalded to death when runaway trams burst a steam pipe at the underground boilers (see Disasters, below). The Inspector's account records that he afterwards had double cocks fitted so that there was little possibility of any repetition.

The Patent Nut and Bolt Company took over in 1872 and in 1879 drove another heading, the Cwmbran Adit, at a lower level about a mile down the valley from the Mine Slope; it linked underground with the older workings and became the main entrance and coal delivery point. By 1896 the colliery employed 798 people on gas, coking, manufacturing and steam coal from the Black Vein and Meadow Vein.

By 1908 Cwmbran, Henllys and the Fire Clay collieries were owned by Guest, Keen and Nettlefolds and employed 1,218 between them; Henllys and the Main Adit were later linked, and about 1916 the Mine Slope closed and its ventilating fan was moved to the Henllys shaft. A report of 1923 gives 1,201 employed on the Elled, Red Ash, Old Coal, Meadow Vein and Black Vein. Production ceased in 1927.

Geology

The colliery worked the outcropping seams of the Gwent coal basin on the eastern slopes of Mynydd Maen. The coalfield geologist Henry K. Jordan recorded from a visit in 1877 that in the adit the Carboniferous Limestone stands nearly vertical, and that the drift begins in the Old Red Sandstone and runs through the Main Limestone and Millstone Grit for 2,080 yards before it intersects the Black Vein, continuing a further 1,180 yards in that seam at a dip of one in eleven and a half. The named seams are the Black Vein, Meadow Vein, Elled, Red Ash and Old Coal.

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

Workings

Adits and slopes rather than shafts: the Porthmawr Nos. 1 and 2 levels of the late 1830s, the Mine Slope of 1854, and the Cwmbran Adit driven in 1879 a mile down the valley at a lower level, which linked underground with the older workings and became the main entrance. The whole drive from the adit mouth to the end of the workings in the Black Vein ran 3,260 yards in a straight line, which Jordan called a larger winning of coal than any other adit in South Wales.

Closure

Production ceased in 1927.

What remains

No account of the site as it is now is recorded. Welsh Coal Mines reproduces a photograph of the remains of the Mine Slope taken in 1970.

Related mines

• Henllys Colliery — Worked together by the Patent Nut and Bolt Company; Henllys carried the Cwmbran ventilating fan from about 1916.

Disasters & major incidents

• Cwmbran Colliery scalding, 1866
  26 April 1866 · Machinery · 3 fatalities
  At about half past two in the morning of 26 April 1866 a haulier bringing trams along the main horse road at Cwmbran Colliery came past the underground boilers too fast. The trams flew off the plates and knocked down the upright pipe carrying the cock used to blow the boilers through, and live steam poured out so fiercely that none of the three men there escaped. The Inspector had double cocks fitted afterwards.
• Cwmbran Colliery roof fall, 1893
  13 January 1893 · Collapse / Roof Fall · 2 fatalities
  A timberman and a fourteen-year-old boy retimbering a road at Cwmbran Colliery on 13 January 1893 were buried by a fall that went unnoticed for hours.
• Cwmbran Colliery roof fall, 1905
  7 March 1905 · Collapse / Roof Fall · 2 fatalities
  A fall of roof in an old stall being stowed with rubbish killed two young men knocking out timber at Cwmbran Colliery in March 1905; the rescuers carried the first body to the wrong house.

What's uncertain

Points where sources disagree or the record could not be settled; both accounts are kept. All open questions in the archive.

• The BGS mine-plans catalogue holds a Mining Remediation Authority abandonment plan titled 'Cwmbran' (catalogue 1983, Meadow., dated 1886); the catalogue gives no location and the plan's details do not clearly tie it to this working, so it may belong to another of the same name. (uncertain) ³

Recorded claims

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

• The first known instance of a colliery at Cwmbran is shown on Charles Halsall's Mineral and Agricultural Map of 1811; in the late 1830s two levels, the Porthmawr Nos. 1 and 2, were driven into the eastern slopes of Mynydd Maen at Upper Cwmbran, No. 2 mainly producing clay and being known as the Fire Clay Level. ¹
• Reginald J. Blewitt of Llantarnam Abbey, member for the Monmouth Boroughs, owned the mine; in December 1837 its first coals went by tramroad to the newly erected wharf at Caerleon, and he shipped several cargoes to London and advertised the coal in the metropolitan papers as similar to Tredegar coal in quality. ¹
• In 1843 the colliers went on strike over an enforced reduction of fivepence per ton of coal, and several miners were sentenced to one month's imprisonment with hard labour for breaching their contracts of employment. ¹
• The coalfield geologist Henry K. Jordan, writing in 1908 of a site visit in 1877, recorded that the adit effected a larger winning of coal than any other adit in South Wales: the drift commences in the Old Red Sandstone and continues through the Main Limestone and Millstone Grit for 2,080 yards from its mouth before intersecting the Black Vein seam, then a further 1,180 yards in that seam at a dip of one in eleven and a half, making 3,260 yards in a straight line. ¹
• The Patent Nut and Bolt Company took over the running of the colliery in 1872 and in 1879 drove another heading, the Cwmbran Adit, at a lower level about a mile down the valley from the Mine Slope; it linked underground with the older workings and became the main entrance and coal delivery point. ¹
• By 1908 Cwmbran, Henllys and the Fire Clay collieries were under the ownership of Guest, Keen and Nettlefolds Ltd, employing 1,218 men in total; about 1916 the Mine Slope was closed and its ventilating fan moved to the Henllys shaft; a report of 1923 gives 1,201 employed producing from the Elled, Red Ash, Old Coal, Meadow Vein and Black Vein seams, and production ceased in 1927. ^1,2
• The BGS mine-plans catalogue holds a Mining Remediation Authority abandonment plan titled 'Cwmbran' (catalogue 1983, Meadow., dated 1886); the catalogue gives no location and the plan's details do not clearly tie it to this working, so it may belong to another of the same name. (uncertain) ³

Photographs & further reading

Sources

1. (secondary) Cwmbran Colliery — Welsh Coal Mines
2. (primary) Cwmbran Colliery — Durham Mining Museum
3. (primary) BGS / Mining Remediation Authority mine plans: CWMBRAN — British Geological Survey / Mining Remediation Authority

Record created: 10 September 2026 · Last researched: 10 September 2026