Cwmgwili Colliery

Overview

A National Coal Board anthracite drift near Cross Hands, driven into the Big Vein from about 1960 to work coal left by the closing Cross Hands Colliery. By 1966 it was the most profitable colliery per ton in the United Kingdom. Merged with the neighbouring Lindsay drift in the early 1970s, it lost three men in a roof fall in 1971, was officially closed in the early 1980s but kept working on a small scale, and finally shut in 1996 after privatisation and a failed management buy-out.

History

Shortly before Cross Hands Colliery closed in 1962, the National Coal Board drove two drifts, Cwmgwili and Lindsay, into the Big Vein to work the coal it had left. NMRS dates Cwmgwili's opening to 1960: its main drift was 2,067 feet long at a gradient of one in three, and its take, just over a mile square, was bounded by the Hendre fault to the east and the Bryngwili fault to the west. By January 1964 the NCB was reporting 'exceptionally high' output of 4,000 tons a week, and in 1966 Cwmgwili made more profit per ton than any other colliery in the United Kingdom; it remained in profit in 1967 and appeared regularly in the productivity tables despite very disturbed geology. On 7 September 1971 three colliers were killed by a single fall of roof in a heading (see Disasters, below). The NCB then merged Cwmgwili with Lindsay, installing a new conveyor and bunker system so coal went up the Lindsay drift at up to 450 tonnes an hour; NMRS dates the scheme to 1972 at £150,000, Welsh Coal Mines to 1970 at £170,000. During the 1972 strike feeling ran so high that the men withdrew safety cover against union advice. In 1974 the colliery employed 363 men underground and 42 at the surface, and in 1978 379 men produced 126,360 tonnes from the Stanllyd seam, over ten miles of roadways 1,200 feet below ground. When the R1 face in the Rock seam met five faults and advanced only six feet in six weeks, and the remaining Stanllyd and Big Vein pillars had been worked, the colliery was officially closed in the early 1980s, but 21 men carried on working by pillar and stall until 1992. It was then privatised, passing to UK Consolidated Mining (1992-93) and Coal Investments (1993-96), and a management buy-out as Jewel Limited failed; Cwmgwili finally closed on 21 November 1996.

Geology

Anthracite from the Big Vein and later the Stanllyd and Rock seams; sections recorded include Ddugaled 0.75 m, Stanllyd 0.75 m, Gras Uchaf 0.7 m, Braslyd 0.56 m and Braslyd Fach 0.44 m. The take lay between the Hendre and Bryngwili faults and the ground was extremely disturbed.

Geological setting: Sedimentary Beds and Seams (well documented example)

Workings

A slant or drift, the main drift 2,067 feet long at 1 in 3, merged with the Lindsay drift in the early 1970s so that coal was conveyed and bunkered up the Lindsay drift. About 1980 it had ten miles of roadways and two miles of conveyors at 1,200 feet; faces included the R1 in the Rock seam, and in 1971 a Joy continuous miner was in use in a 12-foot heading.

Closure

Officially closed by the NCB/British Coal in the early 1980s (Welsh Coal Mines: 1980) after the R1 face in the Rock seam hit faulted ground and the Stanllyd and Big Vein pillars were exhausted. Small-scale pillar-and-stall working continued; after privatisation and a failed buy-out it closed on 21 November 1996 (NMRS), though Welsh Coal Mines says production ceased in 1994.

What remains

Unknown.

Unknown.

Redevelopment

Unknown.

Related mines

• Cross Hands Colliery — Driven to work the Big Vein coal left by Cross Hands Colliery as it closed in 1962.

Nearby mines

• Blaenau Saron Colliery — 3.7 km NE
• Caerbryn Colliery — 3.8 km NE
• Blaenhirwaun Colliery — 4.0 km NW
• Emlyn Colliery — 4.3 km N
• Cross Hands Colliery — 4.9 km N

Straight-line distance, within 15 km. Show on the map.

Disasters & major incidents

• Cwmgwili Colliery Roof Fall, 1971
  7 September 1971 · Collapse / Roof Fall · 3 fatalities
  A sudden fall of roof in a heading being driven with a continuous miner buried three of the five men working there at Cwmgwili, then one of the Coal Board's most productive and profitable collieries. The other two escaped unhurt.

Recorded claims

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

• Cwmgwili was an NCB anthracite slant opened into the Big Vein in 1960, its main drift 2,067 feet long at 1 in 3, to mine coal left by the closed Cross Hands Colliery. ¹
• Just before Cross Hands Colliery closed in 1962, the NCB drove two drifts, Cwmgwili and Lindsay, into the Big Vein anthracite seam. ²
• In January 1964 output reached 4,000 tons a week, and in 1966 Cwmgwili made the most profit per ton of any colliery in the UK. ¹
• By 1970 Cwmgwili was one of the most productive mines in Britain despite extremely disturbed geological conditions. ²
• In 1972 the NCB merged Cwmgwili with the old Lindsay Colliery at a cost of £150,000. (disputed) ¹
• In 1970 a £170,000 scheme merged the two mines. (disputed) ²
• Manpower 445 (1964), 459 (1970), 405 (1972), 390 (1974, 157,000 tons), 379 (1978, 126,360 tonnes), 327 (1980, 135,025 tons). ¹
• Officially closed in the early 1980s but 21 men worked pillar and stall until 1992; after UK Consolidated Mining, Coal Investments and a failed Jewel Limited buy-out it really closed on 21 November 1996. (disputed) ¹
• It was closed by British Coal in 1980 but kept working under Coal Investments plc; production ceased in 1994. (disputed) ²
• The BGS mine-plans catalogue holds plans for 'Cwmgwili Drift, Cross Hands, Rhos' dated 1980 and for Cwmgwili and Lindsay (Cwmgwili) spoil tips dated 1973 and 1996. ³

Photographs & further reading

Sources

1. (secondary) Cwmgwili Colliery — Northern Mine Research Society (Ray Lawrence)
2. (secondary) Cwmgwili Colliery — Welsh Coal Mines
3. (primary) BGS / Mining Remediation Authority mine plans: CWMGWILI DRIFT, CROSS HANDS, RHOS (1980) — British Geological Survey / Mining Remediation Authority

Record created: 16 September 2026 · Last researched: 16 September 2026