Aberfan Cemetery Two rows of white arches near the top of the cemetery mark the graves of the children killed in the colliery tip disaster of 1966. Aberfan disaster Aberfan was the site of one of the worst ever peacetime disasters to occur in the UK. On the morning of 21 October 1966 a tip, where waste from Merthyr Vale Colliery was heaped up, slid down onto Pantglas Junior School destroying most of the school as well as a farm and twenty houses. Children in the school had just left their morning assembly when an avalanche of half a million tonnes of waste debris crashed in to the classrooms. 116 children aged 7-10 were killed out of a total death toll of 144. The subsequent inquiry firmly blamed the National Coal Board, which owned and managed the colliery; the tip, which covered several springs, was known to be unstable - there had been slides before - and prior to the day of the disaster there had been a prolonged period of rain.