Pwll Patch Colliery

Overview

Pwll Patch Colliery was a shallow pit feeding the Cyfarthfa Iron Works, Merthyr Tydfil, working the Nine-Feet and Four-Feet seams and connected underground to the Glyndyrys and Cwm Levels.

History

Pwll Patch is recorded only briefly: a shallow pit sunk to feed the Cyfarthfa Works, working the Nine-Feet and Four-Feet seams and connected to the Glyndyrys and Cwm Levels. No operating dates, output or named deaths survive for it in the source. The British Geological Survey's district memoir for Merthyr Tydfil describes these same two seams in general terms rather than at Pwll Patch itself: the Nine-Feet (the Big Vein of the west of the coalfield) as the district's most important and most worked coal, and the interval between the Bute and Nine-Feet seams as unusually thin -- as little as 0.25 m -- in 'the old Plymouth and Castle pits of Merthyr Tydfil', the same disturbed, thinly-spaced seam structure that runs through the Cyfarthfa group generally. This is used here as geological context for the seams the colliery is recorded as working, not as a second, mine-specific account of Pwll Patch's own operation.

Recorded claims

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

• Pwll Patch was a shallow pit sunk to feed the Cyfarthfa Works, working the Nine-Feet and Four-Feet seams, connected to the Glyndyrys and Cwm Levels. ¹
• The Nine-Feet seam that Pwll Patch worked was the most important and most extensively worked coal in the Merthyr Tydfil district; in the old Plymouth and Castle pits nearby the interval between it and the overlying Bute seam narrowed to as little as 0.25 m. ²

Sources

1. (secondary) Small Collieries around Merthyr Tydfil — Northern Mine Research Society
2. (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: 15 September 2026