MineArchiveAsh Tree Pit, Tredegar
| Also known as | Pwll Mary Isaac |
|---|---|
| Location | Tredegar, Sirhowy valley, Blaenau Gwent — 51.7678, -3.2474 (exact) |
| Commodity | Coal |
| Type | Coal |
| Worked | 1826–1897 |
| Maximum depth | Unknown. |
| Operators | Tredegar Iron Company (1826–1897) |
Overview
A water-balance pit sunk in 1826 to feed the Tredegar ironworks, known as Pwll Mary Isaac after the dairywoman whose cottage stood beside it, which worked until 1897.
History
Ash Tree Pit was one of the many pits the Tredegar Iron Company let out to contractors to feed its works. It was sunk in 1826 or 1827 as a water-balance pit and was long known as Pwll Mary Isaac: Mary Isaac kept milking cows and her dairy supplied the people of Tredegar for many years after the works began, and the pit was sunk close to her small thatched house, which took her name.
The pit worked the Elled seam, and the deeper seams of the Middle and Lower Coal Measures. H. Jones was its manager in 1878. It was closed in 1897 and the shaft filled.
Geology
South Wales Coalfield: the Elled and deeper seams of the Middle and Lower Coal Measures.
Workings
A water-balance pit.
Closure
Closed and filled in 1897.
What remains
Unknown.
Redevelopment
Unknown.
Related mines
- Dukes Pit, Tredegar — Early water-balance pits of the Tredegar ironworks.
- Mountain Pit, Tredegar — Tredegar Iron Company water-balance pits above the ironworks.
- Yard Level, Tredegar — Tredegar Iron Company workings around the Tredegar ironworks.
Nearby mines
- Whitworth Colliery (Tredegar) — 0.3 miles (0.6 km) SE
- Mountain Pit, Tredegar — 0.4 miles (0.7 km) NW
- Yard Level, Tredegar — 0.4 miles (0.7 km) N
- Graham's Navigation Colliery — 0.6 miles (0.9 km) NE
- Ty Trist Colliery — 0.6 miles (1.0 km) SE
Straight-line distance, within 9 miles (15 km). Show on the map.
Recorded claims
Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.
- Ash Tree Pit, also called Pwll Mary Isaac, was sunk in 1826. 1,2
- It was sunk in 1826/7 as a water-balance pit and worked the Elled seam. 3
- It was named after Mary Isaac, whose dairy supplied Tredegar and whose thatched house stood beside it. 2,3
- It closed in 1897 and was filled. 1,2
Sources
- (secondary) NMRS: The Tredegar collieries — Northern Mine Research Society
- (secondary) Engine Pit, Mountain Colliery and Ash Tree Colliery, Tredegar — Welsh Coal Mines
- (secondary) Tredegar Pits — Welsh Coal Mines
Record created: 18 October 2026 · Last researched: 18 October 2026