Between 1977 and 2005, six lethal failures of dumps and landfills of municipal solid waste were recorded in technical literature. Volumes of waste mobilised varied from about 12,000m 3 in a failure that killed more than 600 people, to 1.5M. m 3 in a failure that caused no deaths or injuries.
The lecture brieflly describes and analyses the six failures and summarises their causes. Dumps and landfi lls are man-made structures and it is clear that man's lack of knowledge and technical incompetence regarding the effects of water and slope angle on the stability of slopes was the major cause of all six failures.
The only long-term remedy is to improve the training and understanding of those who operate dumps and landfi ls to eliminate unplanned dumps and replace them by correctly managed and operated engineered landfills.
Geoffrey Blight is professor emeritus at the University of The Witwatersrand, South Africa. After the disastrous flow failure of coal waste dumps at Aberfan in 1966, he carried out a survey of coal waste dumps in South Africa. One hillside dump was found to be life-threatening and removed.
He also investigated South Africa's 1994 Merriespruit tailings dam failure and the 1997 failure of the Bulbul landfill in Durban. He was the BGA Rankine Lecturer in 1997.