Dyllas Colliery

Overview

A group of steam-coal drifts at Llwydcoed, north of Aberdare, opened in 1840 by Matthew Wayne of the Gadlys Ironworks and worked by D. R. Llewellyn and Sons from 1914 into the 1930s.

History

Dyllas Colliery, at Llwydcoed on the northern edge of Aberdare, was opened in 1840 by Matthew Wayne of the Gadlys Ironworks. It grew into a group of drifts, the Old, New and Lower Dyllas, driven into the Nine Feet seam near its northern outcrop. The Six Feet, nine and a half feet thick here, was worked extensively, and the inspector described the Nine Feet at Dyllas in 1894 as about 21 feet thick. The steam-coal measures were followed down to about 250 yards below the surface.

The Gadlys Iron Company owned it by 1873, Waynes Company Limited in 1892 and Waynes Merthyr Company of Gadlys from 1894, when 185 men worked the drift and level under William Pugh. Listed in 1913 as Llwydcoed or Dyllas, it then belonged to Llwydcoed Collieries Ltd, formed by directors of Lancaster's Steam Coal Collieries, and employed 331. On 1 January 1914 D. R. Llewellyn and Sons took it over; it employed 360 in 1916 and 1920, with Henry Jones as manager into the 1930s.

In 1923 it was working the Four, Five, Six, Seven and Nine Feet and the Yard seams. Welsh Coal Mines has it closing in 1927; NMRS still lists 145 men there in 1935, producing steam coal. It was not worked by the National Coal Board. Two men died in an explosion of firedamp in 1894, and a man and a boy of fourteen were drowned in an inrush of water in 1911 (see Disasters, below).

Geology

South Wales coalfield, steam-coal measures of the Cynon valley: the Nine Feet near its northern outcrop (about 21 feet thick in 1894), the Six Feet at nine and a half feet, and the Four, Five, Seven Feet, Yard and Bute seams.

Workings

A group of drifts and a level: the Old, New and Lower Dyllas, driven into the Nine Feet near its outcrop.

Closure

Closed in 1927 according to Welsh Coal Mines; NMRS lists it working with 145 men in 1935. Not worked by the National Coal Board.

What remains

Unknown.

Redevelopment

Unknown.

Related mines

• Gadlys Colliery — Both worked by the Wayne family's Gadlys company (Waynes Merthyr).
• Llwynhelig Colliery — Both D. R. Llewellyn and Sons collieries.
• Tirherbert Colliery — Both D. R. Llewellyn and Sons collieries in the 1910s-30s.
• Windber Colliery — Both D. R. Llewellyn and Sons collieries.

Disasters & major incidents

• Dyllas Colliery explosion, 1894
  10 November 1894 · Explosion · 2 fatalities
  A firedamp explosion in Wayne's Merthyr Dyllas level above Llwydcoed on 10 November 1894 burned three; a collier of thirty and a boy of fifteen died.

What's uncertain

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

• Closed in 1927. (disputed) ¹
• Still employed 145 men in 1935. (disputed) ²

Recorded claims

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

• Opened at Llwydcoed in 1840 by Matthew Wayne of the Gadlys Ironworks. ¹
• Owned by the Gadlys Iron Company from at least 1873. ²
• Acquired by D. R. Llewellyn and Sons on 1 January 1914. ^2,1
• Worked the steam-coal measures to a vertical depth of about 250 yards. ¹
• The Six Feet seam was nine feet six inches thick at Dyllas. ²
• Closed in 1927. (disputed) ¹
• Still employed 145 men in 1935. (disputed) ²

Photographs & further reading

Sources

1. (secondary) Windber drift mine, Cwmdare; Llwynhelig; Dyllas — Welsh Coal Mines
2. (secondary) Dyllas Colliery — Northern Mine Research Society
3. (primary) BGS mine plans: Dyllas Drift, Bute (Dirty) — British Geological Survey / Mining Remediation Authority

Record created: 7 October 2026 · Last researched: 7 October 2026