The Val di Stava Dam collapse occurred on 19 July 1985, when two

tailings dam A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Tailings can be liquid, solid, or a slurry of fine particles, and are usually highly toxic and po ...

s above the village of Stava, near

Tesero Tésero (''Tiézer'' in local dialect) is a ''comune'' (municipality) in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located in the Val di Fiemme about northeast of Trento. The municipality of Tesero contains the ''fr ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

, failed. It resulted in one of Italy's worst disasters, killing 268 people, destroying 63 buildings and demolishing eight bridges. The upper dam broke first, leading to the collapse of the lower dam. Around 180,000 cubic metres (6,350,000 ft³) of mud, sand, and water were released into the Rio di Stava valley and toward the village of Stava at a speed of 90 km/h (56 mph). Having crashed through the village, the torrent continued until it reached the Avisio River a further 4.2 km (2.6 mi) away, destroying everything in its path.

Cause

An investigation into the disaster found that the dams were poorly maintained and the margin of safe operation was very small. A pipe in the upper dam used to drain water had begun to sag under the weight of

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

, making the dam's drainage less effective. Meanwhile, water continued to be pumped into the reservoir behind the dam, which, coupled with the less efficient drainage, meant the pressure on the

bank A bank is a financial institution that accepts deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital markets. Because ...

of the upper dam began to increase. Following the

path of least resistance The path of least resistance is the physical or metaphorical pathway that provides the least resistance to forward motion by a given object or entity, among a set of alternative paths. The concept is often used to describe why an object or entit ...

, water began penetrating the bank, causing the soil within to liquefy and weaken the bank until it failed. The water and

tailings In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different to overburden, which is the waste rock or other material that overli ...

from the upper dam then flowed into the lower dam, which, under the immense pressure produced, failed thirty seconds later. In June 1992, 10 people were convicted of culpable disaster and multiple manslaughter for their roles in the accident and were all sentenced to prison.

References

External links

Stava tailings dam failure

Stava official site Fondazione Stava 1985 onlus
{{coord, 46, 19, 14.09, N, 11, 30, 2.41, E, display=title Dams in Italy Man-made disasters in Italy Floods in Italy 1985 disasters in Italy 1985 in Italy Manslaughter trials Tailings dam failures July 1985 events in Europe

Cause

See also

References

External links