On this day in 1966, an avalanche of mud and rocks buries a school in Aberfan, Wales, killing 148 people, mostly young students. The elementary school was located below a hill where a mining operation dumped its waste.
Aberfan is a small mining village in the Taff River Valley. A substantial number of the village's residents worked at the Merthyr Vale Colliery, a coal mine that had been privatized by the National Coal Board in 1947. At the Merthyr Vale mine, 36 tons a day of ash, coal waste and sludge were produced. This was piled up in what was known as a tip. The largest Merthyr Vale tip was nearly 700 feet high at the time of the accident.
Down a large hill from this tip sat a small farm and the brick Pant Glas elementary school, as well as some homes. In the days leading up to October 21, there was heavy rain in the area. Some mine workers noticed cracks in the tip, but nothing was done to investigate further. The morning of October 21 dawned dark and damp; the area was covered by a thick fog. At about 9 a.m., mine workers heard a loud noise and through the fog saw that the immense tip had disappeared.
The tip had crashed down the hillside onto the farm, the school and eight homes. Thick black dust enveloped the entire village. The muddy sludge was 45 feet deep outside the school and much of the school itself was buried. There were about 250 people in the school when the avalanche hit and more than half were initially missing. Among those who survived, many had severe injuries. The speed and power of the avalanche had ripped appendages right off of some victims.
Parents and rescue workers immediately began to dig through the debris to find the children. The last survivor to be pulled clear was out within the first two hours. The next six days of digging brought out only dead bodies, including those of 116 children. The body of the deputy head teacher was found with the bodies of five children in his arms.
Harold Wilson, Britain's prime minister, visited the scene and promised an inquiry. After five months of investigation and the deposition of more than 100 witnesses, it was determined that the tip had blocked the natural course of water down the hill. As the water was soaked into the tip, pressure built up inside until it cracked, with devastating results. The site of the disaster later became a park.
taken from: http://www.history.com/this-day-in-history/mudslide-buries-school-in-wales [21.10.2013]