At 9.15 am on 21st October 1966 one of a series of coal tips on the Mynydd Merthyr ridge above the west side of the town of Aberfan slid down the hillside, destroying a farmhouse, 20 houses and Pantglas School, which stood below the tip. One hundred and forty four people lost their lives, including 116 children (half the children of the school), five teachers, including the headmistress, and 23 other adults. Most of the dead are buried in Aberfan Cemetery (nprn 86801).

The former tip and slide area occupies a section of the west side of the Taff valley. It is a smoothly graded unenclosed area, almost from the top of the ridge (about 380m ASL) down to the town (about 180m). The ground drops smoothly down to the valley and blends seamlessly with the valley slopes to either side. The area is now bissected by the A470 dual carriageway, which runs north-south across its lower end. Between the A470 and the town, above the Garden of Remembrance (411051), the steep slope is grass and scrub covered, with a track running straight up the slope to the road. The disused railway line at the foot of the slope is now in use as a public footpath.

Grading has formed two areas of slightly stepped contouring: one at the foot of the slope with substantial banks and ditches along the contours; the other more pronounced at the top, to the north-west, with five terraces contoured around the slope reinforced by lines of low concrete walling. Small areas on the lower grading have been planted with mixed deciduous trees, the upper end is now bounded by conifer plantations, and strips of deciduous woodland have been planted alongside the A470.

The tips were made up of rock and soil waste from Merthyr Vale Colliery (80485) which originally started to produce coal in 1875. By 1916 the colliery had run out of space on the valley floor for waste and began tipping on the mountainside above the village. Tipping continued until 1966 by which time seven tips had been constructed. Tip 7 was begun in 1958 and at the time of the disaster it was 34m high. It covered material which had previously slipped in 1944, on the same watercourse that had caused earlier failures. Its catastrophic failure in October 1966 was the result of a build-up of water in the tip.

Sources:

Cadw Historic Assets Database (PGW (Gm) 69(MER)).

Institute of Civil Engineers website: https://www.ice.org.uk/what-is-civil-engineering/what-do-civil-engineers-do/aberfan-disaster-lessons-learnt (accessed 17.6.2020)

Additional notes: D.K.Leighton

RCAHMW, 3 February 2022