New Dynant Colliery

Overview

An anthracite shaft and slant at Cwmmawr in the Gwendraeth Valley, opened in 1901, which employed 560 men with Closyryn in 1920-22. Part of United Anthracite from 1924, it had dwindled to 18 men by the war and closed under the National Coal Board.

History

New Dynant Colliery, a shaft and a slant at Cwmmawr in the Gwendraeth Valley, was opened in 1901 by New Dynant Anthracite Collieries Limited. It was idle in 1907, but by 1908 employed 31 men under F. W. Davies, and by 1913 260 under J. E. Gomersall. A new company, the New Dynant Anthracite Colliery (1914) Ltd of Martin's Lane, Cannon Street, London, was formed in 1914; the workforce reached 420 in 1916 and, with Closyryn, 560 in 1920-22.

In 1923 the owners were the Great Mountain Collieries Company, with 372 men underground and 131 on the surface at the pit and slant, producing 110,000 tons from the Pumpquart and Triquart seams. The company became part of United Anthracite Collieries Limited in 1924, which in 1935 employed 400 men in the New Dynant and Closyryn mines. The colliery had its own washery. It abandoned the Stinking Vein in May 1926. In 1938 the slant employed 297 men.

Four deaths are recorded in 1911-13, each a single accident: a pumpsman crushed by runaway trams when a haulage rope broke, two men under falls of roof, and a stoker who fell pulling out hot ashes. By 1943-45 only 18 men were employed, working the Braslyd seam, and on nationalisation in 1947 the National Coal Board placed it in its No. 1 (Swansea) Area with 18 men. It closed around that time; Welsh Coal Mines gives 1952.

Geology

Anthracite from the Pumpquart and Triquart seams, later the Braslyd; the Stinking Vein was abandoned in 1926.

Workings

A shaft and a slant, with an upcast pit, and its own coal preparation plant (washery).

Closure

Reduced to 18 men by 1943-45 and closed under the National Coal Board, around 1947 by one account and in 1952 by another.

What remains

Unknown.

Redevelopment

Unknown.

Related mines

• Great Mountain Colliery — Owned by the Great Mountain company in 1923; the BGS plans record New Dynant as Great Mountain No. 3.

What's uncertain

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

• It closed around the time of nationalisation in 1947, with 18 men. (disputed) ²
• It was closed by the NCB in 1952. (disputed) ¹

Recorded claims

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

• The anthracite shaft and slant was opened in 1901 by New Dynant Anthracite Collieries Limited. ^1,2
• In 1916 it employed 420 men under H. Mainwaring. ^1,2
• In 1923 it employed 503 men and produced 110,000 tons. ^1,2
• In 1935 United Anthracite Collieries employed 400 men in the New Dynant and Closyryn mines. ^1,2
• It closed around the time of nationalisation in 1947, with 18 men. (disputed) ²
• It was closed by the NCB in 1952. (disputed) ¹

Photographs & further reading

Sources

1. (secondary) Cwmgwili Colliery — Welsh Coal Mines
2. (secondary) NMRS: New Dynant Colliery — Northern Mine Research Society
3. (primary) BGS / Mining Remediation Authority mine plan: GREAT MOUNTAIN NO 3, NEW DYNANT, SLANT & UPCAST PIT (Bute (Braslyd)) — British Geological Survey

Record created: 11 October 2026 · Last researched: 11 October 2026