The location for the disaster was the village of Stava, in Trento.\u00a0 At the site, two tailings dams, built to contain the waste from a fluorite mine, had been constructed.\u00a0 The site, and the collapse, is described in a post-event analysis (Chandler and Tosatti 1995)<\/a>, available online, whilst there is also a nice reflective piece about the role of regulation (Luino and Degraff 2012<\/a>), also available online.\u00a0 The latter includes this image of the tailings dams prior to failure:-<\/p>\n The Stava tailings dams prior to failure. Image from summer 1983, published in Luino and De Graff (2012)<\/a>.<\/p><\/div>\n .<\/p>\n The dams collapsed on 19th July 1985 at 12:22.\u00a0 The initial failure occurred in the upper tailings dam, which then induced collapse of the lower facility in a domino effect.\u00a0 At the time of failure, 300,000 m\u00b3 of material was stored in the two tailings dams.\u00a0 Of this, 180,000 m\u00b3 was released in a single event, which mobilised into a very rapid mudflow.\u00a0 Eyewitness accounts suggest that the rate of movement was sufficiently great to generate an air blast that shredded the trees along the path of the flow.\u00a0 There is a good seismic data for the landslide, which suggests that it reached a peak velocity of 27 metres per second (about 100 km\/h or 60 mph).\u00a0 The mudflow struck the houses located directly below the tailings dams before sweeping down to the village of Stava, located about 800 m below the lower dam.\u00a0 Luino and De Graff (2012)<\/a> report that Stava was struck at 12:25, and the 20 or so buidings were completely destroyed in just 13 seconds.<\/p>\n The flow then travelled down the valley, ultimately sweeping through parts of the town of Tesero, located about 3 km downstream.\u00a0 The before and after image below, also from Luino and De Graff (2012)<\/a>, shows the extraordinarily destructive power of this flow:-<\/p>\n Before and after images of the track of the mudflow from the 1985 Stava tailings dam failure. Image from Luino and De Graff (2012)<\/a>.<\/p><\/div>\n .<\/p>\n The mudflow from the Stava tailings dam failure finally stopped when it reached the main channel of the Avisio river at Tesero.\u00a0 The seismic data suggests that the movement event arrested just ten minutes after the initial collapse.\u00a0 The village of Stava had been completely destroyed, and there was extensive damage in Tesero.\u00a0 In total 268 people were killed, and 56 houses, six industrial buildings and nine other buildings were destroyed.<\/p>\n Subsequent analysis of the site (see Chandler and Tosatti (1995)<\/a> suggests that the stability of the tailings dams was unacceptably low, primarily because the underlying ground was poorly drained, the construction meant that the dams lacked adequate drainage (allowing high water pressures to develop, and preventing proper consolidation of the tailings), the ponds were being recharged with runoff from the adjacent drainage basins, and the upper dam was unacceptably steep, with a part of the retaining structure being sited on tailings from the lower pond.<\/p>\n The failure led to legal action against those responsible for the dam.\u00a0 In June 1992 a total of ten individuals were convicted of crimes that included culpable disaster and manslaughter of multiple individuals, and were jailed.<\/p>\n The Stava Foundation has a very detailed website<\/a> that documents the disaster in order to remember the victims, the aim of which is to promulgate the lessons from the Stava tailings dam failure.\u00a0 Sadly, the industry has yet to heed the lessons adequately<\/a>.<\/p>\n Chandler, R.J. and Tosatti, G. 1995.\u00a0 The Stava tailings dams failure, Italy, July 1985<\/a>. Proceedings of the Institution of Civil Engineers Geotechnical Engineering<\/em>, 113<\/strong> (2), 67-79.<\/cite><\/p>\n![\"Stava](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2019\/09\/19_09-Stava-1.jpg\")
![\"The](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2019\/09\/19_09-Stava-2.jpg\")
References<\/h4>\n