1 February 2019
First thoughts on the Brumadinho dam collapse video
Posted by Dave Petley
First thoughts on the Brumadinho tailings dam collapse video
The video that has emerged today in Brazil showing in high resolution the collapse the Brumadinho tailings dam is apparently genuine, no matter how sensational this might seem. The video is on Youtube, and is absolutely amazing:-
.
Let me include three stills from this video that illustrate what appears to have happened. The first shows the very start of the failure process At the crest of the dam active deformation can be seen – the dark line is a scarp forming as the mass moves downwards. The toe is probably bulging, but this is not really clear:-
The inititiation of failure at the Brumadinho tailings dam. Still from a Youtube video.
.
The second shows the failure fully developed. The slope is going through a massive rotational failure that extends across the full width and involves the full height of the dam:-
The front of the mass is starting to break up. The third shows the transition to a high velocity flow:-
The development of failure and transition to a flow at the Brumadinho tailings dam. Still from a Youtube video.
.
Further rotational slips are occurring on the back scarp, but the front of the flow is travelling very rapidly. To me this look to have the characteristics of a debris avalanche rather than a debris flow – the presence of so much dust suggests that this frontal portion might not be saturated. But I would be interested in other views.
The remarkable thing here is that the mass failed as a single landslide involving the full width and full height. There is now sense of a small slip destabilising the mass, or of a series of events, or of retrogression. I find this surprising.
There is also footage now of the flow downstream. That is also deeply alarming:-
.
I really hope that this video will bring home the need for proper tailings management, and thus worldwide change. There can be no better illustration of just how terrifying and deadly these failures can be.
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.
Thanks for posting this! I’d like to see a longer first video to see what happens afterwards… sort of a teaser.
@Scott …. this is what happened next: https://youtu.be/FKpmB9-SVIo
Dear Scott, there is a longer video:
https://www.youtube.com/watch?v=hvVYhBkiYnQ
And this one contains a longer video from the camera on top of the dam:
https://www.youtube.com/watch?v=ip0am7UExVw
This 6 min video is the highest quality I found so far. They zoom in and replay different parts of the videos. It’s recorded from the most viewed news program in Brazil:
https://www.youtube.com/watch?v=xSmjaP1cUAk
The people on the pickup and excavator managed to survive:
https://translate.google.com/translate?sl=pt&tl=en&u=https%3A%2F%2Fg1.globo.com%2Fmg%2Fminas-gerais%2Fnoticia%2F2019%2F02%2F01%2Fsobrevivente-escapa-de-tragedia-da-vale-em-uma-picape-que-foi-levada-pela-lama.ghtml
I found the official media channels of Minas Gerais’ firefigthers.
There are dozens of photographs and videos from their perspective.
The links are at the bottom of this page
http://www.bombeiros.mg.gov.br/component/content/article/32-embm/73081-cbmmg-brumadinho.html
Also near those links there is another one “Confira mais fotos da operação em Brumadinho”, which is a Google Photo album that seems to be constantly updated. It’s also very dramatic.
On their Youtube there are some low altitude footage from the rescue helicopters.
And today’s (Feb 1st) tribute to the victims, one week after the collapse, still missing 248 people:
https://www.youtube.com/watch?v=JNEj5UxOtak
Dave,
are there any reliable undergound remote sensing technique for mud conditions like these? I mean, to look for bodies.
So incredibly rare to have such quality imaging of the initiation and development of a massive failure. Combined with the transverse footage from the crane (?), it should allow detailed modelling…
What I found the most scary part was there seemed no warning. No prior kinks or fractures, no apparent leaks from the toe. It just {expletives deleted} failed…
Given the reported surveys found nothing amiss, this suggests some basic assumption is wrong, with world-wide implications…
I wonder what were the people doing on that plateau of this closed dam at the moment of failure. Where they the fugro employees? Were they drilling? Why or what for?
Inácio Garcia! People were working normally after an evaluation of the engineers at the dam, the engineers claimed that everything was under control, so the company put the workers to extract the ore. It was not a natural accident, it was a purposeful disaster, the owner of the company Vale has to answer for this mass murder! For many people who lived in the villages, animals in the forests, livestock in the farms, and fish contaminated in the rivers, and generations still died with this contamination that will last for many years! 315 dead.
Could this be due to static liquefaction?
It appears to me that the bulge at the base develops along the center line of one of the drainage lines. If drainage were impeded then it would not take much added stress (drilling maybe?) to produce excess pore pressures and trigger static liquefaction whereby mobilization of the entire mass would not be unheard of.
Could it be a bursting of a jellyfied (liquefied) oversaturated tailings right above the “soil compacted dykes” at Elevation 900 due to high pore-water pressure built-up in the tailings (pls. see the cross-section)? Please note the burst of tailings, it looks like as if the gates of a dam have just opened-up.
An FS value of 1.14 was mentioned in the paper by W. Pirete, R.C. Gomes (2013), calculated for static loading. This FS value should be questioned for sufficiency for stability, considering that the shear strength parameters of tailings are highly variable and SPT/CPT testing would not solely be relied on.
Also, it appears that there was no diversion channel to prevent surface run-off to get into the tailings dam. Excessive rainfall in December and January in the region could have caused over-saturation of the tailings that would lead to a liquefaction-type failure.
Please note that there was no reported free water on the dam top surface; but the”whole mass of tailings” were washed out: A sign of over saturated mass…
Of course, all of the above thougths are based on remote info available.
This appears to be a static liquefaction failure.
administrators Vale do Rio Doce Campany – Vale and operators and Brazilian governments are corrupt and do not care about human life and so you will be a foreigner who decides to live in Brazil so you will be treated in the same way
They are employees of a company called Vale do Rio Doce – VALE and worked in various sectors that cover mining and also works on the slopes of the dam that broke, the dam or soil were not being drilled, only broke through the excess of accumulation of tailings in the poorly constructed and inspected dam and poorly monitored by this company that exploits the Brazilian soil and by directors who are trash of Vale and mother fuck owners
Hi John, this is the failure of Fundão Dam (2015).
Please watch the video in increments…. bulging at the toe (actually, above the toe, apparently at the top level of the “soil compacted dykes”) starts at the same time of the displacements at the upgradient boundary of the tailings dam reservoir; and the toe blasts out like a quickly-squeezed toothpaste. Then the the whole tailings material flows out. Any commens?
The initial bulging at the toe reminds me of pulling the plug out of a bathtub.
Dear Ignacio, Vale made a statement about that:
http://www.vale.com/EN/aboutvale/news/Pages/Vale-clarifies-about-people-at-the-dam-drainage-warning-siren-and-escape-route.aspx
This driller survived.
https://g1.globo.com/mg/minas-gerais/noticia/2019/02/03/vi-o-gramado-abrindo-igual-um-vulcao-conta-sobrevivente-que-estava-em-cima-da-barragem-em-brumadinho.ghtml
My money is on an initial static liquefaction failure as in Fundao, then shear failure caused by unloading at the toe as in quick clays.
I agree, the toe blew out like a cork. I am a mining engineer and have study tailings dam construction.
After viewing GoogleEarth image of dam, it appears there are 2 distinct tailings structures. I believe an expansion/addition was placed on top of an original structure. The original design would not have incorporated such additional loading and mining co’s do not over-build by much (ie small safety factor in load design). A cursory review of the original design shortcoming would be “cured” by the significant (flat zone visible from above ) setback of the second tier.
The large over-pressure on the original tails would push on the clay toe like toothpaste in a tube and the cap was the lower structure.
That should read “The large over-pressure on the original tails would push on the CLAY-CAPPED toe like toothpaste in a tube and the cap was the lower structure.”
(The material I believe that impacts the first structure so violently is compacted dry clay. The momentum displayed would be consistent with such, in my opinion.)
Thanks for sharing amazing information. I appreciate it, keep it up.