Garn Colliery, Blaenavon

Overview

The Blaenavon ironworks' Garn Pit of about 1839, with its unusual line-in winding, and the Garn Slope of 1881 that kept the colliery working until it was merged with Big Pit in the 1960s.

History

Garn Colliery, about a mile from Big Pit at Blaenavon, was a pit, a slope and a level. The Blaenavon iron works company sank the Garn Pit about 1839 to feed its ironworks, at first working the deeper ironstone and later concentrating on coal. The pits were sunk 90 yards to the Bottom Vein Mine ironstone, with a drift of 120 yards west to the rising Old Coal seam. Ventilation was by a furnace at the pit bottom.

Its winding gear was unusual. The two drawing shafts, about six yards apart, shared a single beam engine whose ropes came off the top and bottom of one drum, so that a cage was lowered in one shaft as the other rose. Each carriage raised a 27-hundredweight tram, and two tank locomotives on 3 ft 4 in tramplates took the coal to the coke yard above the blast furnaces. Daily output was 250 tons of coal and 50 tons of iron ore. In 1896 the Garn Pits employed 137 men underground and 27 on the surface.

The company, reformed in 1880 as the Blaenavon Company Ltd, sank the No. 2 or Garn Slope in 1881, connected underground to the Garn pits, Milfraen and Kay's Slope. The pit ceased production in 1903 but was kept to serve the slope, and a new drift became the main adit in 1925. In 1935 the colliery employed 1,500 underground and 700 on the surface; at nationalisation in 1947 678 men worked the Yard, Nine-Feet, Meadow Vein and Garw seams. Garn was merged with Kay's Slope in 1958 and with Big Pit on 1 January 1961; production ended in the 1960s. Thirty miners had died there by 1947, seventeen of them under roof falls.

Geology

The north-east crop of the South Wales Coalfield. The pit was sunk to the Bottom Vein Mine ironstone, 4 ft 8 in of measures holding about 7 inches of ore. The Old Coal (Five-Feet/Gellideg) was 4 ft 8 in with clod partings, about three feet of it good coal; the Bydelog was also worked, the level took the Horn Coal (Lower Nine-Feet), and the slope later worked the Yard, Black, Meadow Vein, Nine-Feet and Garw seams.

Workings

Two drawing shafts about six yards apart, wound by one 28-inch beam engine with a 14-foot drum, and a furnace upcast twenty yards away. Engine planes ran 450 yards down the Old Coal and 440 yards down the Bottom Vein, worked longwall on the south side and pillar and stall on the north. The Garn Slope (No. 2) of 1881 and a new drift of 1925 later carried the colliery.

Closure

The pit ceased production in 1903 and was kept to serve the slope. The colliery was merged with Kay's Slope in 1958 and Big Pit in 1961; production ended in 1963 after years in the Garw seam, and the colliery finally closed in 1966.

What remains

Unknown.

Redevelopment

Unknown.

Related mines

• Big Pit — Garn was merged with Big Pit on 1 January 1961; both belonged to the Blaenavon Company before nationalisation.
• Milfraen Colliery — Garn Slope was connected underground to Milfraen, and the two were returned together with Kay's Slope in 1908.

Recorded claims

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

• The pit was sunk about 1839 by the Blaenavon iron works company to feed its ironworks, with furnace ventilation at the pit bottom. ^1,2
• The line-in winding gear allowed simultaneous winding in one split shaft or two adjacent shafts, the ropes coming off the top and bottom of the drum. ¹
• Daily output was 250 tons of coal, 50 tons of iron ore and 150 tons of rubbish. ¹
• In 1896 the Garn Pits employed 137 men underground and 27 on the surface, working the Old Coal, Bydelog and Bottom Vein ironstone. ^1,2
• The Blaenavon Company Ltd sank the No. 2 or Garn Slope in 1881, and a new drift opened in 1925. ²
• Garn Colliery was merged with Kay's Slope in 1958 and with Big Pit on 1 January 1961, and finally closed in 1966. ²
• Production at Garn Slope ceased in 1963 after working the Garw seam for many years. ¹
• Up to 1947 thirty miners died at the colliery: seventeen under roof falls, five in haulage accidents and eight from other causes. ²

Photographs & further reading

Sources

1. (secondary) Garn Pit, Blaenavon - Welsh Coal Mines — Welsh Coal Mines
2. (secondary) Garn Colliery - Northern Mine Research Society — Northern Mine Research Society

Record created: 1 October 2026 · Last researched: 1 October 2026