Castle Pit, Troedyrhiw

Overview

A steam-coal pit at Troedyrhiw, south of Merthyr Tydfil, sunk by Crawshay Brothers of Cyfarthfa in 1866, the company's first pit sunk to sell coal rather than supply its ironworks. It employed more than 1,300 men by 1913, passed to Llewellyn (Cyfarthfa) Ltd and stopped production under Powell Duffryn in 1935.

History

Castle Pit was sunk at Troedyrhiw in 1866 by Crawshay Brothers, the Cyfarthfa ironmasters, to work the steam coal seams. It was the first of the company's pits sunk to produce coal for sale rather than for the ironworks, and it sent the first twenty wagons of Cyfarthfa coal to Cardiff docks. The shaft went down 333 yards. The steam winding engine had a pair of vertical cylinders 36 inches in diameter with a 4 foot 6 inch stroke, driving a 12 foot drum with flat wire ropes, and its double-decked cages could wind from 263 yards in 90 seconds. M. Bates was manager in 1878.

The workforce grew from 686 in 1896, under the manager William Dyer, to 1,272 in 1908 and 1,361 in 1913, with David Francis as manager from 1908 into the 1920s. A Castle Level beside the pit employed about a hundred men until it was abandoned in May 1927. In July 1895 an explosion of gas in the Four Feet seam killed three rippers, Daniel Sullivan, Robert Bodger and a third man named Thomas: a fall of roof had released gas, which met a light as they cleared it. Deaths from falls and other accidents were recorded almost every year.

In the 1920s the pit was linked underground with South Duffryn Colliery, then owned by the Plymouth company. By 1925 it belonged to Llewellyn (Cyfarthfa) Ltd, whose only mines were Castle and the Berry Level; in 1934 it employed 1,030 men and raised 270,000 tons. Powell Duffryn Associated Collieries took control in 1935 and stopped production, with the loss of 300 jobs. The National Coal Board kept it as a pumping station, with five men there in 1947. The site now lies under the A470 road.

Geology

The steam coal measures of the Taff valley. The pit had over 64 feet of coal in vertical total, 41 feet of it in seams more than two feet thick: the Gorllwyn (18 inches), Two-Feet-Nine (about 60 inches), Upper Four Feet (66 inches), Six Feet (60 inches), Seven Feet (33 inches) and the Gellideg (10 feet 7 inches of mixed coal and dirt). Its Nine Feet coal was classed as types 202 and 203, weak to medium coking steam coals, low in volatiles, ash and sulphur.

Workings

A single shaft sunk to 333 yards, with the Castle Level alongside. Seams worked included the Six Feet, Seven Feet, Nine Feet and Upper Yard (1923), and the Castell-y-Weiver, Four Feet, Lower Four Feet and Red Vein later; the workings were linked to South Duffryn Colliery in the 1920s.

Closure

Powell Duffryn Associated Collieries took control in 1935 and stopped production, with the loss of 300 jobs. The National Coal Board used the shaft as a pumping station, employing five men there in 1947.

What remains

The site is buried under the A470 road.

None; the site lies under the A470.

Redevelopment

The A470 trunk road was built over the site.

Related mines

• South Duffryn Colliery — Linked underground to Castle Pit in the 1920s; both appear on one set of abandonment plans.

Recorded claims

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

• Sunk in 1866 by Crawshay Brothers (Cyfarthfa) to 333 yards, the company's first pit sunk to produce coal for sale. ¹
• The pit employed 1,272 men in 1908 and 1,361 in 1913. ¹
• An explosion of gas in the Four Feet seam in July 1895 killed three rippers. ^1,2
• Fatal accidents were recorded at Castle, Troedyrhiw, in each year from 1901 to 1903. ³
• The Castle pits appear with Plymouth, South Duffryn and North Duffryn on one set of abandonment plans. ⁴
• Powell Duffryn Associated Collieries took control in 1935 and stopped production. ¹

Photographs & further reading

Sources

1. (secondary) Welsh Coal Mines: Castle Pit, Troedyrhiw — Welsh Coal Mines
2. (primary) 'Terrible explosion at Troedyrhiw. Three men killed', Merthyr Times, 25 July 1895 — Welsh Newspapers Online (National Library of Wales)
3. (secondary) NMRS coal mining accidents and deaths database: Coytrahén Park, Tondu — Northern Mine Research Society
4. (primary) BGS / Mining Remediation Authority mine plan: PLYMOUTH / SOUTH DUFFRYN / NORTH DUFFRYN / CASTLE PITS / NO 1 SARON — British Geological Survey

Record created: 10 October 2026 · Last researched: 10 October 2026