Cinder Pits

Overview

Workings of the Blaenavon Company at the head of the Eastern Valley, taking their name from the cinder tips of the ironworks they served. On 28 November 1838, after two days of rain and snow, a cloudburst over Waun Afon and the Coity sent a wall of water down the valley which burst the embankment protecting the mouth of the Old Level and drowned fifteen people underground, five of them children — Blaenavon's worst industrial accident, and worse than anything that happened at Big Pit.

History

The Cinder Pits were part of the coal and iron works of the Blaenavon Company at the head of the Eastern Valley in Monmouthshire, the concern whose ironworks and, later, Big Pit made Blaenavon a World Heritage Site. Their name comes from the cinder — the waste of the iron furnaces — tipped beside them. The workings were reached by the Old Level, a drift whose mouth stood behind an embankment raised to protect it from the river.

That embankment is why the pits are remembered. On 28 November 1838 the river came over it and drowned fifteen people in the workings (see Disasters, below). The dead included Mary Hale, sixteen, and Elizabeth Harvard, nine, and boys of ten, twelve and fourteen: this was six years before the Mines Act of 1842 took women and girls out of British mines had reached everywhere, and their names are on the list with everyone else's.

What survives of the Cinder Pits is the accident: their sinking, their seams, their output and their end are not recorded.

Geology

The workings lay in the coal and ironstone measures at the head of the Eastern Valley, the same ground worked by the Blaenavon Company's ironworks pits and levels and later by Big Pit. Nothing is recorded of the particular seams worked at the Cinder Pits.

Workings

Reached by a drift, the Old Level, leading to what the contemporary account calls the Deep Coal and Iron Works of the Blaenavon Company. The mouth of the level was protected from the river by an embankment — the arrangement that failed in 1838. Nothing else about the layout of the workings is known.

Closure

The closure date is not known. The workings belong to the first half of the nineteenth century and to the Blaenavon Company's ironworks era.

What remains

Nothing is recorded of the site. Blaenavon and its industrial landscape are a UNESCO World Heritage Site, and the Blaenavon Ironworks and Big Pit, both close by, are open to visitors.

Redevelopment

Unknown.

Disasters & major incidents

• Cinder Pits Inundation, 1838
  28 November 1838 · Flooding / Inundation · 15 fatalities
  After two days of incessant rain followed by snow, the sky over Waun Afon and the Coity darkened about midday on 28 November 1838 and discharged. The water inundated the works, nearly filled the valley, raised the river by many feet and burst over the embankment protecting the mouth of the Old Level at Blaenavon. Fifteen people in the workings were drowned, five of them children and two of them girls. It was Blaenavon's worst industrial accident.

Recorded claims

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

• Fifteen people were drowned at the Cinder Pits, Blaenavon, on 28 November 1838 when water burst into the workings; the Welsh Coal Mines fatality list names all fifteen and gives the cause as inundation of water. ¹
• The Blaenavon World Heritage Site's own history of Big Pit records that Blaenavon's worst industrial accident did not take place at Big Pit: in November 1838 the Cinder Pits were flooded and fifteen miners, including five children, drowned. ²
• The workings were reached by the Old Level, leading to the Deep Coal and Iron Works of the Blaenavon Company, whose mouth was protected by an embankment that the flood burst over. ¹

Photographs & further reading

Sources

1. (secondary) Welsh mining fatalities, 1838: Cinder Pits, Blaenavon, inundation of water, 15 killed — Welsh Coal Mines
2. (secondary) Big Pit: A Brief History — Blaenavon World Heritage Site

Record created: 3 September 2026 · Last researched: 4 September 2026