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The Kolontár red mud dam failure (Hungary)

(last updated 25 Dec 2010)


The dam failure and its impacts

On October 4, 2010 at 12:30 p.m. the embankment of basin X of the red mud reservoir failed and released a mixture of 600-700 thousand cubic metres of red mud and water. The slurry flooded the lower sections of the settlements of Kolontár, Devecser and Somlóvásárhely via the Torna creek. Ten people were killed, and approx. 120 people were injured. The spilling red mud flooded 800 hectares of surrounding areas. The most severe devastation was caused in the villages of Devecser and Kolontár, which are located near the reservoir.

The dam is owned by the privately held company Magyar Alumínium ZRt (MAL - Hungarian Aluminum Co). The red mud is a highly caustic waste generated by the processing of bauxite in MAL's alumina plant in Ajka (Veszprém County).
The main component contained in the red mud is Fe2O3 (iron oxide - which gives it its characteristic red colour) at 40-45%. Other components are Al2O3, SiO2, CaO, TiO2, and Na2O, according to MAL.
On Oct. 5, 2010, Greenpeace took samples of the red mud to have them analyzed for any contaminants. The results were reported on Oct. 8 and Oct. 12, 2010: 110 mg/kg for arsenic, 1.3 mg/kg for mercury, 660 mg/kg for chromium (of which only 0.46 mg/kg for the highly toxic hexavalent chromium Cr-VI), 40 mg/kg for antimony, 270 mg/kg for nickel, and 7 mg/kg for cadmium.
On Oct. 12, 2010, Greenpeace also started measurements of the particulate matter in ambient air. First results obtained in Devecser for PM10 were in the 60 - 300 mikrogram per cubic metre range; the standard of 50 g/m3 may be exceeded on 35 days per year only. The results for PM2.5 were 30 g/m3.

The European Union has sent a group of five experts to assist Hungary. One of the experts is Pia Lindström external link, the person in charge of environment at the mining branch of Boliden external link, the Swedish company that in 1998, in a similar disaster at its Los Frailes mine in Spain, contaminated the surroundings of Doñana National Park and that has not paid a Euro for the repair of the damages. (El País Oct. 11, 2010)

On Oct. 11, 2010, Zoltán Bakonyi, chief executive officer of MAL was arrested, but released again on Oct. 13, 2010.
On Oct. 12, 2010, the company's management was taken over by the state.

In the morning of Oct. 14, 2010, an increase in the width of the cracks in the impoundment walls was observed.


The causes of the dam failure

Presentation by Dr Caner Zanbak (Turkish Chemical Manufacturers Association): Failure mechanism and kinematics of Ajka tailings pond incident, 4 Oct. 2010 external link, 10 Dec. 2010 (4MB ZIP file containing PDF file). The author concludes that

"The dike failure was probably:





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