Rhymney Merthyr Colliery

Overview

A Rhymney Iron Company colliery at Pontlottyn, also known as Tynewydd, its two shafts sunk from 1889 to the Rhas Las seam at 335 yards. No. 1 stopped on New Year's Eve 1922, but No. 2 closed and reopened three times over the next fifteen years and was still pumping in 1945.

History

Rhymney Merthyr Colliery stood at Pontlottyn in the upper Rhymney valley and was also known as Tynewydd. Its two shafts were sunk by the Rhymney Iron Company, No. 1 in 1889-90 and No. 2 in 1892, to work the Rhas Las seam, which was reached at 335 yards. It was opened to produce coking, house, manufacturing and steam coals for the company's own ironworks trade. No. 2 was later deepened to 316.4 metres, cutting the Four-Foot at 192.9 metres, the Nine-Foot or Rhas Las at 239.7 metres and the Five-Feet/Gellideg at 291.5 metres. It grew quickly. In 1896, under the manager J. Powell, it employed 344 men underground and 35 at the surface. By 1907 that had become 768 underground and 523 at the surface, and in 1908, under J. W. Pugh, No. 1 pit held 430 men and No. 2 held 878. The total workforce stood at 1,078 in 1918. The Rhymney Iron Company became a subsidiary of Powell Duffryn in 1920. Then it came apart in stages. Production ceased at No. 1 pit on New Year's Eve 1922. No. 2 carried on with a fraction of the men — 57 underground and 32 on the surface in 1923 — closed for a while during 1924, reopened the same year, and closed again in 1928. Powell Duffryn reopened it in 1937 and employed 481 there in 1938. By 1945 No. 2 alone was still open, kept for pumping and ventilation with twenty men. The company's own records leave one thing unsettled: the same account gives the No. 1 sinking as 1889-90 and elsewhere as a sinking to the Four-Foot in 1892, with No. 2 reaching the Rhas Las in 1897. The colliery may also have been called Duffryn Rhymney, though in 1894 the Rhymney pit and the Duffryn Rhymney were returned separately, at 110,000 and 75,385 tons.

Geology

Worked the Rhas Las seam of the upper Rhymney valley at 335 yards, with the Four-Foot above it at 192.9 metres and the Five-Feet/Gellideg below at 291.5 metres in the deepened No. 2 shaft.

Workings

Two shafts, No. 1 and No. 2, sunk by the Rhymney Iron Company to the Rhas Las seam at 335 yards. No. 2 was afterwards deepened to 316.4 metres, passing the Four-Foot at 192.9 metres, the Nine-Foot or Rhas Las at 239.7 metres and the Five-Feet/Gellideg at 291.5 metres, and it was No. 2 that was kept on at the end for pumping and ventilation.

Closure

Production ceased at No. 1 pit on New Year's Eve 1922. No. 2 worked on, closed briefly in 1924 and again in 1928, was reopened by Powell Duffryn in 1937 with 481 employed by 1938, and by 1945 was kept open only for pumping and ventilation with twenty men.

What remains

Cleared. The colliery site at SO 1215 0555 above Pontlottyn is recorded by industrial archaeologists as an open site, with the colliery weir the most substantial structure still standing.

The colliery weir, and the cleared ground of the colliery site itself.

Redevelopment

Unknown.

Related mines

• Gilfach Colliery — Both worked by the Rhymney Iron Company in the Rhymney Valley.

Nearby mines

• McLaren Colliery — 1.7 km SE
• Ogilvie Colliery — 2.2 km S
• Cae Glas Colliery — 2.9 km NW, Merthyr Tydfil
• New Tredegar Colliery — 3.6 km SE
• Rhas Las Colliery — 3.6 km NW, Merthyr Tydfil

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

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 same account gives No. 1 as sunk in 1889-90 and, in a separate note, as sunk to the Four-Foot seam in 1892, with No. 2 reaching the Rhas Las in 1897. (disputed) ¹

Recorded claims

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

• The two shafts were sunk in 1889-90 and 1892 by the Rhymney Iron Company, reaching the Rhas Las seam at 335 yards. ¹
• In 1908 it employed 430 men at the No. 1 pit and 878 at the No. 2, and by 1918 its total workforce was 1,078. ¹
• Production ceased at Rhymney Merthyr No. 1 on New Year's Eve 1922. ¹
• The workings are recorded in the mine-plans catalogue of the British Geological Survey. ²
• The two shafts were sunk by the Rhymney Iron Company, No. 1 in 1889-90 and No. 2 in 1892, to work the Rhas Las seam at a depth of 335 yards. No. 2 was later deepened to 316.4 metres, meeting the Four-Foot at 192.9 metres, the Nine-Foot or Rhas Las at 239.7 metres and the Five-Feet/Gellideg at 291.5 metres. ¹
• In 1896, under the manager J. Powell, the colliery employed 344 men underground and 35 at the surface; by 1907 it was 768 and 523. In 1908, under J. W. Pugh, No. 1 pit employed 430 and No. 2 employed 878, and by 1918 the total workforce was 1,078. ¹
• Production ceased at No. 1 pit on New Year's Eve 1922. No. 2 employed 57 underground and 32 on the surface in 1923, closed for a time during 1924 and reopened the same year, closed again in 1928, and was reopened by Powell Duffryn in 1937, employing 481 in 1938. In 1945 only No. 2 remained open, for pumping and ventilation, with twenty men. ¹
• The same account gives No. 1 as sunk in 1889-90 and, in a separate note, as sunk to the Four-Foot seam in 1892, with No. 2 reaching the Rhas Las in 1897. (disputed) ¹
• The colliery site above Pontlottyn, at SO 1215 0555, has been cleared; the colliery weir is the most substantial structure recorded as still standing there. ³

Photographs & further reading

Sources

1. (secondary) Rhymney Merthyr Colliery (Welsh Coal Mines) — Welsh Coal Mines
2. (primary) Rhymney abandonment plans (BGS mine-plans catalogue) — British Geological Survey
3. (observational) Northern Rhymney Valley: industrial archaeology and history — Industrial Gwent

Record created: 23 September 2026 · Last researched: 23 September 2026