Garth Colliery, Tonmawr

Overview

A Wenallt-seam colliery near Tonmawr, first recorded as Blaenmawr Colliery in 1917, worked as Garth from 1929 and by the National Coal Board until its reserves ran out in 1964.

History

Garth Colliery began as Blaenmawr Colliery, recorded both near Tonmawr and near Cymmer. A National Coal Board broadsheet gave its opening as 1864, but it is first recorded in 1917, owned by D. Edwards and Sons, who in 1918 employed 50 men underground and 8 on the surface under the manager W. J. Jenkins. The Blaenmawr Colliery Company owned it from 1921, with about 90 men. In March 1926 the haulier John Williams was killed when he jumped from a tram to check a horse that had quickened its pace on seeing daylight.

In July 1929 the colliery was in the hands of a receiver; Garth Collieries Ltd took it over and called it Garth or Blaenmawr. In 1935, as Garth Nos. 1 and 3, it employed 150 men underground and 45 on the surface and raised 50,000 tons from the Wenallt seam, under Gwyn Lloyd, who managed it into the 1950s. On 4 September 1942 it opened one of the first government canteens in the South Wales coalfield, serving hot meals with room for 200 men.

The National Coal Board took it over in 1947, when it employed 201 men, and it worked the Wenallt and Wenallt Rider seams, including those of the old Merthyr Llantwit Colliery, until it closed for exhaustion of reserves on 20 June 1964.

Geology

South Wales Coal Measures. The colliery worked the Wenallt and Wenallt Rider seams.

Workings

Garth Nos. 1 and 3 by 1935, working the Wenallt and later the Wenallt Rider; it later worked the seams of Merthyr Llantwit Colliery.

Closure

Closed by the National Coal Board on 20 June 1964 because its coal reserves were exhausted.

What remains

Unknown.

Redevelopment

Unknown.

Related mines

• Merthyr Llantwit Colliery — Garth later worked the seams of Merthyr Llantwit Colliery.

What's uncertain

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

• A National Coal Board broadsheet gives the opening date of Blaenmawr as 1864, but no record of it is found until 1917, when it was owned by D. Edwards and Sons. (uncertain) ¹

Recorded claims

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

• A National Coal Board broadsheet gives the opening date of Blaenmawr as 1864, but no record of it is found until 1917, when it was owned by D. Edwards and Sons. (uncertain) ¹
• In 1929 the colliery was in the hands of the receiver and was taken over by Garth Collieries Limited, who called it Garth or Blaenmawr. ^2,1
• In 1935 it employed 45 men on the surface and 150 underground working the Wenallt seam, producing 50,000 tons, manager G. Lloyd. ²
• On 4 September 1942 the colliery had one of the first government canteens in the South Wales Coalfield, with room for 200 miners. ²
• The colliery was closed by the NCB on 20 June 1964 due to the exhaustion of its reserves of coal. ²
• Abandonment plans are catalogued for Garth Tonmawr in the Wenallt and Wenallt Rider seams. ^3,4
• The seams of Merthyr Llantwit Colliery were later worked by Garth Colliery, Tonmawr. ⁵

Photographs & further reading

Sources

1. (secondary) Blaenmawr Colliery - Northern Mine Research Society — Northern Mine Research Society
2. (secondary) Garth Tonmawr Colliery - Northern Mine Research Society — Northern Mine Research Society
3. (primary) BGS mine plans: Garth Tonmawr, Fan (Wenallt, Wenallt Rider) — British Geological Survey / Mining Remediation Authority
4. (primary) BGS mine plans: Garth Tonmawr (Wenallt Rider) — British Geological Survey / Mining Remediation Authority
5. (secondary) Whitworth Colliery, Tonmawr — Welsh Coal Mines (Glamorgan West) — Welsh Coal Mines

Record created: 2 October 2026 · Last researched: 2 October 2026