MineArchiveClwydyfagwr Colliery
| Location | Merthyr Tydfil |
|---|---|
| Commodity | Coal |
| Type | Coal |
| Worked | Unknown.–1919 (not listed thereafter); a separate later drift abandoned 1938 |
| Operators | John Harris (1896–1907), R. Harris (1907–1919), T. L. Williams (1935–1938) |
Overview
Clwydyfagwr Colliery was a small level near Merthyr Tydfil working the Twenty Inches and Two-Feet-Nine seams for steam coal, owned by John Harris and later R. Harris. A separate, later drift of the same name was worked in the 1930s but defeated by flooding and poor coal.
History
The colliery was owned by John Harris in 1896, employing six men underground and five on the surface. By 1907 R. Harris owned it, employing seven men, falling to three underground and one on the surface in 1908; it employed six underground and two on the surface in 1918 and was not listed in 1919. It worked the Twenty Inches and Two-Feet-Nine seams for steam coal. A separate Clwydyfagwr (or Glwydyfagwr) Drift worked the Twenty Inches seam between 1935 and 1937, owned by T. L. Williams, who had little luck with it: between October and December 1936 he produced only 32 tons against an expected 108 because of flooding, and by 1937 the coal was judged inferior and unsuitable. It was shown as abandoned in 1938. The British Geological Survey's district memoir for Merthyr Tydfil describes the Two-Feet-Nine as 'a good steam coal in the Merthyr and Aberdare area', matching the colliery's own recorded use of the seam, though the memoir does not name Clwydyfagwr itself.
Recorded claims
Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.
- Clwydyfagwr Colliery, owned by John Harris in 1896 and R. Harris by 1907, worked the Twenty Inches and Two-Feet-Nine seams for steam coal with a workforce that varied from three to eleven men. 1
- A separate Clwydyfagwr (Glwydyfagwr) Drift, owned by T. L. Williams, worked the Twenty Inches seam from 1935, was badly affected by flooding in 1936 and judged to be producing inferior coal by 1937, and was abandoned in 1938. 1
- The Two-Feet-Nine seam that Clwydyfagwr worked was a good steam coal in the Merthyr and Aberdare area, though poor in quality and thickness west of Hirwaun. 2
Sources
- (secondary) Small Collieries around Merthyr Tydfil — Northern Mine Research Society
- (primary) Geology of the South Wales Coalfield, Part V, the country around Merthyr Tydfil (Memoir, Sheet 231) — British Geological Survey
Record created: 15 September 2026 · Last researched: 16 September 2026