Duffryn Navigation Colliery

Overview

Duffryn Navigation Colliery, Cymmer, was a major Afan Valley employer despite its place among the district's 'small collieries' -- 1,200 to 1,300 men on the books through the early-to-mid 1920s under the Imperial Navigation Coal Company.

History

The NMRS's Afan Valley roundup gives Duffryn Navigation's ownership and workforce rather than its working detail: owned in 1920-24 by the Imperial Navigation Coal Company, managed by D. J. Rees, it employed 1,200 men in 1920-24, 1,300 in 1925-26 and 850 by 1929 -- a scale that puts it well above most of the other small collieries in the same survey. No seams, shafts or depths are recorded for it directly. The British Geological Survey's district memoir for Pontypridd and Maesteg, which covers this part of the Afan Valley, describes the No. 2 Rhondda seam group 'west of Duffryn', where a local split occurs and the lower leaf is known as the Wernddu Rider -- geological description of the immediate area the colliery worked, though the memoir does not name Duffryn Navigation itself.

Recorded claims

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

• Duffryn Navigation Colliery, owned by the Imperial Navigation Coal Company and managed by D. J. Rees, employed 1,200 men in 1920-24, 1,300 in 1925-26 and 850 by 1929. ¹
• The No. 2 Rhondda seam group splits locally in the Avan Valley west of Duffryn, where the lower leaf is known as the Wernddu Rider. ²

Sources

1. (secondary) Small Collieries in the Afan Valley and surrounding areas — Northern Mine Research Society
2. (primary) Geology of the South Wales Coalfield Part IV, the country around Pontypridd and Maesteg — British Geological Survey

Record created: 14 September 2026 · Last researched: 16 September 2026