12 November 2015
The Samarco dam failure – an intriguing video
Posted by Dave Petley
Samarco dam failure
On Youtube there is a video that provides a compilation of videos that are purportedly from the Samarco dam failure that released a mudslide of tailings that destroyed the town of Bento Rodriguez in Brazil a week ago. The video is over 12 minutes long and has clearly been obtained from elsewhere:
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The first sequence shows water cascading through the spillway of a dam. I do not believe that this is anything to do with the Samarco dam failure – it does not seem to fit with the observations of the accident.
The second sequence, starting at about 24 seconds, clearly does show an aspect of the disaster. It is not great quality, but my interpretation is that it shows the area of the Fundao dam shortly after its failure. This appears to be be tailings left in the tailing pond:
The Samarco dam site via Youtube
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Whilst this image appears to be site of the dam itself, or what was left of it. There appears to be a great deal of dust in the air – the remains of the movement perhaps?
Site of the Samarco dam via Youtube
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This actually seems to be the best footage available so far of the site of the Samarco dam, the Fundao dam, that failed, though it does not shed much more light on the disaster.
The next sequence, starting at about 50 seconds, is the most intriguing. This seems to show a very large mudslide arriving in a small rural community in good weather. The slide is enormous and extremely destructive:
Samarco dam mudslide via Youtube
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I am unsure as to whether this is the event at Bento Rodrigues caused by the Samarco dam failure, but its fits the known facts. It is certainly a most impressive landslide.
Most of the remainder of the video shows the damage from the landslide, which has been described elsewhere.
Meanwhile the fallout continues. As Samarco and its owners struggle to manage the disaster and the publicity, and of course the likely costs, there are suggestions in the media that there had been warnings two years ago that the Samarco dam was not safe:-
A 2013 report conducted by The Instituto Pristino linked to the Federal University of Minas Gerais, warned of structural design flaws and predicted the circumstances that could lead to a dam burst at the Samarco operation.
“The report had already highlighted the fragility of these structures and the necessity of increased rigor in monitoring them,” Brazilian state prosecutor Carlos Eduardo Ferreira Pinto said.
This report is available online in Portuguese as a pdf. The report seems to indicate the potential for the Fundao dam to be destabilised by proposed works for Samarco. It is unclear as to whether the recommendations were taken up or whether the effects noted here played a role in the accident.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
I am also confused with the first sequence of the video showing water gushing out of a spillway (presumably), as I have not seen that structure in any other footage or image.
In the first video is the Hydroelectric Plant in Santa Cruz do Escalvado, 100 kilometers from Mariana, which opened the floodgates to vent mud. Companies and environmental agencies do not seem to think of the worst case scenario when licensing activities or design their facilities.
I see, thanks for pointing that out.
I am not sure why the author put that on the video.
I think to attract the attention. Anyway, the impact of this disaster will affect the cities for many years. The Rio Doce is dead, according to some experts. The ecosystems are irreversibly committed. The tailings slurry moves at about 1.2 kilometers per hour from the day 5, when tragedy struck, and will go all the 853 kilometers between the city of Rio Doce, Minas Gerais, to Regencia, Espirito Santo, where meets the Atlantic Ocean.
On this website there is an infographic about the disaster. The first showing of the disaster dynamic until Bento Rodrigues. The second is the full path that the mud will travel to reach the ocean. http://www.em.com.br/app/noticia/gerais/2015/11/12/interna_gerais,707249/infografico-explica-como-foi-o-desastre-de-mariana-e-as-consequencias.shtml
I wanted to share a very nice video of Helicopter footage with no commentary, or audio for that matter. Unfortunately it does not show the dams, but it seems to begin at the beginning of the dam failure and move downstream, showing all the damage left behind the release of the tailings. Some of the best quality video I could find.
https://www.youtube.com/watch?v=Z5FXg7jBv8w
In a video displayed in the program Fantastico of Globo TV, Sunday (16), shows what appears to be a fissure at the Germano dam (images taken by the Fire Department). According to the report, unlike released so far, the Santarem dam did not break. The Mud of Fundao dam filled the reservoir, which was water and went over the dam. The structure resisted but was damaged and is now holding much of the waste of Fundao. http://g1.globo.com/fantastico/noticia/2015/11/fotos-revelam-rachadura-em-outra-barragem-em-mariana.html