The Aberfan disaster
The spoil tip that collapsed onto Aberfan was one of seven heaps of mining waste on the hillside above the village, created from the Merthyr Vale Colliery. The tip that slipped, known as Tip 7, had been started in 1958 and was the only one still in use in 1966. It was built partly on ground where natural springs emerged, a fact that was common local knowledge and had been recorded on official maps for decades. This contravened the National Coal Board’s own procedures. The stability of such tips is heavily affected by water, and several of the other tips had also been sited on streams or springs. Tip 4, for instance, had been started on boggy ground between two streams and experienced a significant slide in 1944, stopping just above the village. Tip 7 itself had shifted slightly in May 1963, and a more substantial slide occurred later that year, which the NCB dismissed as a harmless run-off of tailings—fine coal waste and ash that behaves like quicksand when wet. After that incident, the NCB stopped depositing tailings on Tip 7 but continued adding normal spoil. Aberfan is in an area of high rainfall, and the Pantglas district had suffered severe flooding at least eleven times between 1952 and 1965, with residents complaining that the floodwater was black and left a greasy residue. Complaints about the danger from coal slurry being tipped behind the local schools had been made to the council, who corresponded with the NCB about the matter for nearly a year before the disaster.
- location
- Aberfan, near Merthyr Tydfil, Wales
- cause
- Collapse of colliery spoil tip due to water saturation
- responsible_body
- National Coal Board (NCB)
- inquiry_chair
- Lord Justice Edmund Davies
Lore & Background
The Aberfan disaster occurred on 21 October 1966, when a colliery spoil tip collapsed on a mountain slope above the Welsh village of Aberfan, near Merthyr Tydfil. The tip, known as Tip 7, had been started in 1958 and was the only one still in use at the time. It was built partly on ground from which springs emerged, a direct contravention of National Coal Board (NCB) procedures. The presence of these springs was common knowledge in the area and had been marked on Ordnance Survey and Geological Society maps since 1874. Three other tips on the same slope had also been sited on streams or springs. Aberfan lies on the eastern slope of Mynydd Merthyr, in the Taff Valley, an area of relatively high rainfall. After three weeks of heavy rain, water built up within the saturated tip, causing it to suddenly slide downhill as a slurry. The slide engulfed Pantglas Junior School, where lessons had just begun, and a row of houses, killing 116 children and 28 adults. The disaster was blamed on the NCB and nine named employees by an official inquiry chaired by Lord Justice Edmund Davies. The NCB chairman, Lord Robens, was criticised for misleading statements regarding knowledge of the springs. The remaining tips were removed only after a lengthy fight by residents against resistance from the NCB and government on cost grounds.
Reader's Guide
The Aberfan disaster remains a landmark event in British industrial and disaster history, highlighting the catastrophic consequences of negligence by a nationalized industry. The official inquiry, chaired by Lord Justice Edmund Davies, placed blame squarely on the NCB, whose chairman Lord Robens was criticized for misleading statements. Despite the findings, neither the NCB nor any employees were prosecuted or fined. The remaining spoil tips were removed only after a lengthy fight by residents against NCB and government resistance on cost grounds. In subsequent decades, the British and Welsh governments repaid money taken from the memorial fund, acknowledging the injustice. The disaster also had lasting psychological effects: half of the survivors have experienced post-traumatic stress disorder at some time in their lives.
Common Misconceptions (Editorial)
One common misconception is that the Aberfan disaster was a sudden, unforeseeable landslide caused solely by heavy rain. In fact, the tip had been built over a natural spring, contravening National Coal Board procedures, meaning the risk was both known and preventable. Another misconception is that no single body was responsible; the NCB was explicitly the responsible body for the tip's construction and maintenance.
Why It Matters (Editorial)
The Aberfan disaster endures as a stark reminder of the human cost when institutional negligence is prioritized over safety. It underscores how the failure to follow basic procedures—like building a spoil tip over a spring—can have catastrophic consequences, particularly for the most vulnerable. The tragedy continues to resonate because it was entirely avoidable, making it a lasting symbol of the need for accountability in industrial and regulatory oversight.
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