On the 21 October 1966, 144 people, 116 of them children, were killed when a tip of coal waste slid onto the village of Aberfan in South Wales. I am old enough to remember the news coverage of that disaster and the image above of the mass grave of children's coffins is probably what sticks most in my memory. The death toll of children was so high because their school was right in the path of the mudslide which occurred just after the they had assembled in school at 9am.
I suspect most of you will never have heard of Aberfan. I used to use it as a case study of a mudslide but over the years there have been fewer and fewer pupils who even recognised the name. Today, 40 years on, is a good time to talk about it again.
The tragic events of 40 years ago unravelled as a consequence of both human and physical factors. Heavy rain saturated the unstable and highly permeable coal waste which had been piled high on the valley side (despite many warnings of the danger of this). Underneath was a layer of permeable sandstone and below this an impermeable rock layer. Surface springs had also been blocked by the coal waste and as it was unable to drain, it turned into the 'slurry' which was eventually propelled by gravity down the valley side. Your textbooks contain some information about Aberfan which you might want to read in the section on Mass Movement (pages 81 and 84 in the new editions and pages 86 and 90 in the old editions). There is also a lot of coverage in the press today and on the BBC website. Click on this link to access it and try to find time to read broadcaster John Humphrey's poignant memories of the disaster.
