New Tredegar Colliery

Overview

A Rhymney Valley steam-coal colliery sunk by the Newport merchant Thomas Powell in 1853 and taken over by the Powell Duffryn Steam Coal Company ten years later. It employed well over a thousand men for most of its life. Twenty-two were killed by an explosion in December 1875, the day after the manager had ordered the pit kept clear for twenty-four hours. The colliery was ended in 1929 not by economics but by a landslip.

History

The colliery was sunk in 1853 by Thomas Powell, a Newport merchant, with two shafts each 345 yards deep — one for winding, the other for ventilation and pumping. The Powell Duffryn Steam Coal Company took over the ownership in 1863 and added two more shafts, the last of them sunk in 1905. Before 1900 the colliery used a Struve ventilation system. On 2 December 1875 a minor gas explosion near the coalface badly injured two men. The workings were inspected afterwards and found free of gas, but the manager decided as a precaution that no one should enter the pit for at least twenty-four hours. His orders were disregarded, and the following morning the men went down as usual on the instructions of the overman, William Evans. At eight o'clock a second explosion killed twenty outright and two more died later of their injuries (see Disasters, below). The colliery was a large employer: 1,088 men in 1896 working the Big and Yard seams, 1,156 by 1918, and a 1923 report giving 1,372 producing from the Big Vein, Rhas Las, Yard and Lower Four Feet. It was forced to close in 1929 when the side of the nearby mountain slid and badly damaged two of the shafts. The site was not cleared until 1965.

Geology

The colliery worked the steam coals of the Rhymney Valley, on the eastern side of the South Wales Coalfield — the Big Vein, Yard and Rhas Las among them, the seams that made Powell Duffryn one of the great steam-coal companies. The ground above the colliery was less stable than the ground below it: the mountainside slipped in 1929 and damaged two shafts badly enough to end the pit.

Workings

Two shafts of 345 yards were sunk in 1853, one for winding and one for ventilation and pumping, and Powell Duffryn added two more, the last in 1905. Before 1900 the colliery was ventilated on the Struve system. The seams worked were the Big and Yard, with the Red Vein, Rhas Las, Little Yard Red, No. 4 and Lower Four Feet appearing in the returns over time.

Closure

The colliery was forced to close in 1929 when the side of the nearby mountain slid and badly damaged two of the shafts. The site was not cleared until 1965.

What remains

The colliery site was cleared in 1965. New Tredegar's surviving colliery landmark is the winding house of the separate Elliot Colliery, now the county museum known as The Winding House.

Nothing of this colliery survives; the Elliot Colliery winding house nearby is a different pit.

Nearby mines

• Elliot Colliery — 0.4 km SE
• McLaren Colliery — 2.0 km NW
• Darran Colliery — 3.2 km S
• Bedwellty Pits — 5.0 km N, Blaenau Gwent
• Oakdale Colliery — 5.9 km SE

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

Disasters & major incidents

• New Tredegar Colliery Explosion, 1875
  3 December 1875 · Explosion · 22 fatalities
  A minor gas explosion at New Tredegar Colliery on 2 December 1875 injured two men. The workings were inspected, found free of gas, and the manager nonetheless ordered that nobody should go down for twenty-four hours. His order was disregarded, the men descended the next morning under the overman's instructions, and at eight o'clock a second explosion killed twenty outright. Two more died later, making twenty-two.

Recorded claims

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

• The colliery was sunk by the Newport merchant Thomas Powell in 1853, with two shafts each 345 yards deep — one for winding, the other for ventilation and pumping. (medium) ¹
• The Powell Duffryn Steam Coal Company took over the ownership in 1863 and added two more shafts, the last sunk in 1905. (medium) ^1,2
• 1,088 men were employed in 1896 and 1,156 by 1918. For 1923 Welsh Coal Mines gives 1,372 while the Durham Mining Museum's return gives 1,187. (disputed) ^1,2
• The colliery worked the Big and Yard seams, with the Red Vein, Rhas Las, Little Yard Red, No. 4 and Lower Four Feet appearing in the returns at different dates. (high) ^1,2
• The pit was forced to close in 1929 when the side of the nearby mountain slid, badly damaging two of the shafts; the site was not cleared until 1965. (medium) ¹

Photographs & further reading

Sources

1. (secondary) Old pit, New Tredegar — Welsh Coal Mines
2. (secondary) Durham Mining Museum: New Tredegar Colliery — Durham Mining Museum

Record created: 3 September 2026 · Last researched: 3 September 2026