Brynmally Colliery

Overview

A Denbighshire colliery at Moss near Wrexham, probably sunk in the late 1830s or early 1840s and bought by Thomas Clayton and Company in 1849. It was also known as Pwll y Pendwll. Water broke into its No. 3 pit in 1856, drowning thirteen, and an explosion in the Queen seam of the No. 1 pit in 1889 killed twenty men and boys, many of them children.

History

The colliery was probably sunk in the late 1830s or early 1840s, and was purchased by Thomas Clayton and Company in 1849. It also went by the name Pwll y Pendwll.

On 30 September 1856 water broke into the No. 3 pit and drowned thirteen men (see Disasters, below).

On 13 March 1889 an explosion killed twenty men and boys (see Disasters, below).

A gas explosion at the No. 6, or Forsygo, pit on 30 May 1878 killed six colliers. By 1889 Thomas Clayton's colliery worked the Upper and Lower Queen seams from its Nos. 1 and 3 pits, about 290 yards deep and ventilated by a Schiele fan, with some 200 men and boys underground. The Inspector of Mines' list of 1896 recorded 255 men employed. By 1908 the colliery belonged to the New Brynmally Colliery Company, employing 292; in 1918 the Nos. 1 and 3 pits together employed 482, and in 1923 there were 415 men producing house coal, steam coal and fireclay from the Powell, Queen, Drowsail, Smith and Four Feet seams.

Geology

The colliery worked the Coal Measures of the Denbighshire coalfield, the North Wales field that runs south from the Dee estuary past Wrexham. The Queen seam, named in the 1889 accident, was among its productive coals. Water was a serious hazard in this coalfield's shallower workings, as the inundation of the No. 3 pit in 1856 shows.

Workings

Several shafts, of which the No. 1 and No. 3 pits are named in the accident records. The No. 1 pit worked the Upper and Lower Queen seams. The colliery is also recorded under the name Pwll y Pendwll.

Closure

The closure date is not known for this colliery.

What remains

Nothing is recorded of the present state of the site; the Welsh Coal Mines page for the colliery is marked as still requiring a photograph.

Disasters & major incidents

• Brynmally Colliery inrush, 1856
  1856 · Flooding / Inundation · 13 fatalities
  On Tuesday 30 September 1856 water from old workings broke into the No. 3 pit of Clayton and Darlington's Brynmally Colliery near Wrexham and drowned thirteen men. The first body was not reached for almost four weeks, and a pitman was killed during the pumping.
• Brynmally Colliery (Forsygo pit) explosion, 1878
  1878 · Explosion · 6 fatalities
  On 30 May 1878 an explosion of gas in the No. 6, or Forsygo, pit of Thomas Clayton's Brynmally Colliery near Wrexham, also called Pendwll, killed six colliers.
• Brynmally Colliery explosion, 1889
  1889 · Explosion · 20 fatalities
  On 13 March 1889 a roof fall at Garston's jig in the Queen seam of Brynmally's No. 1 Pit released an outburst of gas that fired at open lamps, killing twenty men and boys, eight of them sixteen or younger. The inspector blamed lax discipline over lamps under the North Wales butty system.

What's uncertain

Points where sources disagree or the record could not be settled; both accounts are kept. All open questions in the archive.

• The colliery was probably sunk in the late 1830s or early 1840s and was purchased by Thomas Clayton and Company in 1849. It also went by the name Pwll y Pendwll. (uncertain) ¹

Recorded claims

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

• The colliery was probably sunk in the late 1830s or early 1840s and was purchased by Thomas Clayton and Company in 1849. It also went by the name Pwll y Pendwll. (uncertain) ¹
• On 30 May 1878 an explosion of gas at the No. 6 Forsygo pit of Thomas Clayton's Brynmally colliery killed six colliers. ¹
• The 1896 Inspector of Mines list records 255 men; by 1908 the New Brynmally Colliery Co. employed 292; in 1918 Nos. 1 and 3 pits employed 482. ¹
• In 1923 there were 415 men producing house coal, steam coal and fireclay from the Powell, Queen, Drowsail, Smith and Four Feet seams. ¹
• In 1889 Thomas Clayton's colliery worked the Upper and Lower Queen seams from Nos. 1 and 3 pits, 290 yards deep, ventilated by a Schiele fan, with about 200 men and boys. ²

Photographs & further reading

Sources

1. (secondary) Brynmally Colliery, Moss, near Wrexham — Welsh Coal Mines
2. (secondary) Brynmally Colliery Explosion - Wrexham - 1889 — Northern Mine Research Society
3. (secondary) Welsh mining disasters: list of accidents with five or more fatalities — Welsh Coal Mines

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