Author: Michele Longo

On 5th November 2015, the Fundão tailings dam, in the district of Mariana, State of Minas Gerais, Brazil, failed. It contained waste material from the Germano iron mine, managed by Samarco Society, a joint venture between the Anglo-Australian Bhp-Billington and the Brazilian Vale, which are two of the most important multinational mining companies worldwide. A mudflow exceeding 30 million cubic metres struck the village of Bento Rodrigues, which was completely destroyed. In addition, the flow ran down the rivers Gualaxo do Norte, Carmel and Rio Doce for over 660 kilometres, eventually reaching the Atlantic Ocean about two weeks after failure.

Around 12:30 hrs of 4th October 2010, the north-western corner of a vast reservoir containing some 30 million cubic metres of waste from an aluminium factory in the village of Ajka, in western Hungary, suddenly collapsed, giving rise to a red mud flow of nearly 1 million cubic metres, which poured out over the surrounding countryside causing an environmental catastrophe. The collapse of the Ajka reservoir on 4th October 2010 The village of Kolontár was struck and partly submerged by the large mass of water mixed with toxic mud from the failed reservoir, taking the inhabitants of the area by

On 12th April 2010, a 10-15 metre wide landslide affecting some 400 cubic metres of rock and soil, fell onto the railway line of the Venosta valley between the stations of Laces and Castelbello in South Tyrol (northern Italy), just when a local train heading to Meran was passing. The violent impact of the landslide caused the derailing of the train. The first car in the convoy was completely destroyed, 9 persons were killed and 28 more were injured, some of them seriously. Water percolation into the soil, caused by a spill from an irrigation system, generated the landslide. The

On 9th March 1976, one of the gondolas of the Cermis cableway collapsed and fell to the ground causing the death of 42 persons. The trial brought to light the fact that the workers in charge of the plant had switched off the safety system, which blocked the movement of the cableway whenever the hauling cable touched the carrying cable. Following strong swaying, the hauling cable overlapped the carrying cable and, since the safety system was switched off, the latter was truncated by the friction, causing the fall of the gondola. On 3rd February 1998, during a training flight, a

In the second half of August 1987, heavy downpours affected the Venosta valley in South Tyrol (Italy), causing a rapid increase in the water level, well beyond safety limits, in the hydroelectric reservoir contained by the Gioveretto dam in the upper Martello valley, a lateral hollow of the Venosta valley. In the months prior to disaster, the managers in charge of the plant had filled up the reservoir in order to have the maximum water availability for the production of electric power during the autumn and winter. Even before intense precipitation, the reservoir’s level was approaching its maximum. In the

The second known disaster due to the failure of mine tailings dams took place on 1st December 1928 in the mining village of Sewell, Chile, where a similar incident had already taken place in 1915. The Barahona sand tailings dam, a facility serving the El Teniente copper mine, located in the Andes south of Santiago, was over 2 km long, 63 m high and contained 29.5 million tons of mine waste material. Following a very strong earthquake, the outer embankment of the tailings dam suddenly collapsed. As a consequence, millions of tons of mud flowed into the riverbeds of the

The first known disaster due to the failure of mine tailings dams took place on 15th June 1915 in the mining village of Sewell, Province of Rancagua, Chile. After days of intense precipitation, there was a mud spill from the summit of the tailings dam’s embankment serving the Agua Dulce copper mine when it was in full activity. Following mud overflowing, the 61 m high embankment collapsed due to flow failure. Some 180,000 cubic metres of material leaked out of the impoundment. No data are available concerning environmental damage or loss of human lives. Chronology of major tailings dam failures