Windsor Colliery

Overview

A deep Aber Valley colliery sunk from 1895, connected underground to the neighbouring Universal Colliery at Senghenydd for ventilation, whose own 1902 shaft accident killed six sinkers before the pit went on to work for the better part of a century.

History

The Windsor Colliery Company Ltd began sinking two shafts at Abertridwr in 1895, eventually reaching around 2,018 feet — among the deepest workings in the South Wales coalfield. First coal was raised in 1902, the same year the underground workings were connected to the neighbouring Universal Colliery at Senghenydd for ventilation, a link that had nothing to do with Universal's own catastrophic 1913 explosion (see that disaster's own record) but did mean the two collieries' air circulation was bound together for as long as both worked. During the shaft-sinking work itself, on 3 June 1902, a working stage collapsed, killing six sinkers (see Disasters, below). A second, lesser accident on 8 April 1910 killed the haulier Thomas Isaac, suffocated by a roof fall on the horse road. The colliery's workforce peaked at 2,550 men in 1925, the same year as its maximum output of 2,550 tons of coal, before the wider coalfield's 1920s downturn cut employment to 860 by 1935. Ownership passed from the Windsor Colliery Co. Ltd to the Powell Duffryn Steam Coal Company in the early 1930s and then to the National Coal Board on nationalisation in 1946. In 1974, Windsor's remaining coal reserves were transferred to the neighbouring Nantgarw Colliery in an attempt to work around Nantgarw's own difficult geology, and by 1976 the two collieries were linked underground and worked as a single unit, with all coal wound and processed through Nantgarw. The combined operation finally closed on 6 November 1986; the Windsor site itself is now occupied by the Ty'n y Parc housing estate.

Workings

Two shafts sunk from 1895 to around 2,018 feet, among the deepest in the South Wales coalfield; connected underground to Universal Colliery, Senghenydd, for ventilation from 1902, and to Nantgarw Colliery from 1976.

Closure

Closed on 6 November 1986, by which point Windsor had been worked jointly with the neighbouring Nantgarw Colliery as a single unit since 1976, its own coal reserves having been transferred there in 1974.

What remains

The former colliery site is now occupied by the Ty'n y Parc housing estate.

Related mines

• Universal Colliery — Windsor's underground workings were connected to Universal Colliery specifically for ventilation from 1902, a genuine structural link between the two collieries rather than mere proximity — though Windsor itself had no direct involvement in Universal's own 1913 disaster.

Disasters & major incidents

• Windsor Colliery Shaft Accident, 1902
  3 June 1902 · Winding / Shaft Accident · 6 fatalities
  A working stage collapsed during shaft-sinking at Windsor Colliery, Abertridwr, dropping eight men into a flooded sump and drowning six of them.

Recorded claims

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

• The Windsor Colliery Co. Ltd began sinking two shafts at Abertridwr in 1895, reaching around 2,018 feet; first coal was raised in 1902. ¹
• During the shaft-sinking work, on 3 June 1902, a working stage collapsed and six sinkers drowned in the flooded sump below — see Disasters, below. ²
• Windsor's underground workings were connected to the neighbouring Universal Colliery at Senghenydd for ventilation from 1902. ¹
• On 8 April 1910, haulier Thomas Isaac died from suffocation caused by a roof collapse on the horse road. ¹
• Workforce peaked at 2,550 men in 1925, the same year as maximum output of 2,550 tons of coal, before falling to 860 men by 1935 amid the wider coalfield's 1920s-30s downturn. ¹
• In 1974 Windsor's remaining coal reserves were transferred to the neighbouring Nantgarw Colliery to work around Nantgarw's difficult geology; by 1976 the two were linked underground and worked as one unit, closing together on 6 November 1986. ¹

Photographs & further reading

Sources

1. (secondary) Windsor Colliery — Wikipedia — Wikipedia
2. (primary) Windsor Colliery Shaft Accident — Abertridwr — 1902 — Northern Mine Research Society

Record created: 2 September 2026 · Last researched: 2 September 2026