(IDEX Online) - The tailings dam that burst at the former Jagersfontein diamond mine, in South Africa, last September, "deviates from best engineering practice," according to a study of satellite images by civil engineering academics. Based on their three-dimensional reconstruction of the failed dam, the authors estimate four to six million cubic meters of diamond mining waste were released in an accident that killed at least two people and covered 350 homes in thick, gray sludge."The deviations include mine waste deposition from predominantly one side of the dam, erosion gullies on the dam wall, and significant amounts of ponded water at times positioned against the retaining structure," say the authors, from the School of Civil and Environmental Engineering at the University of the Witwatersrand, Johannesburg (Wits).The study also emphasizes that "a robust monitoring strategy of tailings dams should focus on their adequate construction and operation."The Jagersfontein mine was closed by De Beers in the 1970s and was bought by Stargems last April. A a dam holding tailings (or waste) from the disused diamond mine burst on 11 September 2022.Stargems said at the time that "a full due diligence was conducted prior to this acquisition showing that the assets, including the dam were safe and secure". A summary of the findings by researchers Dr. Luis Torres-Cruz and Christopher O'Donovan is published on the university's website and in the journal Scientific Reports."We expect our paper to be useful to those interested in understanding how this tragic event came to be and also to help prevent future failures," said Torres-Cruz, who specializes in geotechnical aspects of tailings dams.Satellite image courtesy Wits University