Glyn Merthyr Colliery

Overview

A slant near Resolven in the Vale of Neath, where the disturbed valley floor ruled out deep pits and all the coal was won from hillside levels. Reopened in 1913 by the Ynisarwed Collieries Company, it employed 390 men in 1916 and was working the Red Vein with 220 men in 1930.

History

Glyn Merthyr was one of many slants driven into the outcropping seams on the hillsides above the Vale of Neath. The valley floor here is badly disturbed ground, so no deep mine was ever sunk in this stretch of the valley and every colliery worked from a slant or level along the side. The Glyn Merthyr Colliery Company opened it to produce manufacturing coal. The Ynisarwed Collieries Company reopened it in 1913 to the Nos. 1 and 2 Rhondda seams, and it grew quickly: 225 men in 1913, 390 by 1916 under the manager D. Jones, then 215 underground and 17 on the surface in 1918 under D. Griffiths. The company was not a member of the Monmouthshire and South Wales Coal Owners Association. Manpower fell to 155 in 1919 under G. Dawkins and to 63 in 1920, recovering to 151 in 1924 before dropping again to 28 in 1928. The colliery worked the Ynisarwed seam at about 28 inches and the No. 1 Rhondda at about 24 inches, abandoning the No. 1 Rhondda in March 1925 — the seam and year of the abandonment plan held in the national catalogue. In 1930, under A. Davies, 200 men worked the Red Vein with 20 on the surface, producing 100,000 tons in conjunction with the Red Slant.

Geology

Outcropping seams on the side of the Vale of Neath: the Ynisarwed seam at about 28 inches and the No. 1 Rhondda at about 24 inches, with the Nos. 1 and 2 Rhondda worked from 1913 and the Red Vein by 1930. The valley floor is very disturbed ground, which is why the coal here was worked from slants.

Workings

A slant (level) driven into the hillside outcrop; by 1930 it was worked in conjunction with the Red Slant.

Closure

The No. 1 Rhondda seam was abandoned in March 1925, and the abandonment plan for that seam is catalogued nationally under 1925. The colliery was still at work in 1930 with 220 men; no closure date has been located in the sources read.

What remains

Unknown.

Unknown.

Redevelopment

None recorded in the sources read.

Related mines

• Ynysarwed Colliery — NMRS records Glyn Merthyr as reopened in 1913 by the Ynisarwed Collieries Company, the same concern that worked Ynysarwed, and by 1930 Glyn Merthyr's output was counted in conjunction with the Red Slant.

Recorded claims

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

• The valley bottom around Resolven is very disturbed ground, so no deep mines were sunk there and all the coal was worked from slants or levels along the hillside, Glyn Merthyr among them. ¹
• The Ynisarwed Collieries Company reopened Glyn Merthyr in 1913 to the Nos. 1 and 2 Rhondda seams; it employed 225 men in 1913, 390 in 1916, 155 in 1919, 28 in 1928 and 220 in 1930. ¹
• It worked the Ynisarwed seam at about 28 inches and the No. 1 Rhondda at about 24 inches, abandoning the No. 1 Rhondda in March 1925; the national abandonment-plan catalogue holds a GLYN MERTHYR plan for the No. 1 Rhondda dated 1925. ^1,2
• In 1930, under the manager A. Davies, 200 men worked the Red Vein with 20 on the surface, producing 100,000 tons of coal in conjunction with the Red Slant. ¹

Photographs & further reading

Sources

1. (secondary) Small Collieries at Resolven — Northern Mine Research Society
2. (primary) BGS / Mining Remediation Authority abandonment plan: GLYN MERTHYR, No. 1 Rhondda seam, abandoned 1925 (catalogue 8637) — British Geological Survey
3. (secondary) Ynisarwed Colliery — Welsh Coal Mines

Record created: 14 September 2026 · Last researched: 17 September 2026