4 October 2019
Nosso Senhora do Livramento: another tailings dam failure in Brazil
On 1st October, another significant tailings dam failure occurred in Brazil, this time at Nosso Senhora do Livramento in Mato Grosso. Fortunately, in this case the scale of the failure, whilst not being trivial by any means, was not equivalent to the other two recent events in Brazil. However, two people have been injured.
The best image to provide an overview of this failure is, I think, this one from Isso E Noticia:-
So, it appears that one of the walls of the tailings dam has collapsed. The location is -15.958, -56.479 if you want to take a look. This is the Google Earth image of the site:-
This image was collected in June 2018. Planet Labs captured an image of the site on 1st October 2019, the day of the collapse:-
It is not clear as to whether the failure was on-going when the image was captured, but at that point the extent of the inundation from the failure was quite contained. It is worth comparing the above image with the one below, which is the same site imaged on 7th July:-
I think that there is clear evidence that there was considerable work going on at this site, including clearing of the area that was ultimately inundated. The images also suggest that the height of tailings dam has probably been increased over the last 15 months or so – this is a Planet Labs image from July 2018, when the dam walls appear to be significantly lower:-
The thickness of the tailings dam walls has clearly increased, and at least superficially this raising appears to have occurred via the upstream method (can anyone comment on this?)? This raising of the height of the tailings dam walls might also be evident in the photograph at the top of the page.
There’s a good article (in Portuguese) about the failure in Estadao Ssustenabilidade. This notes that this was a registered gold mine; that the tailings dam was inspected in September 2018 and found to be low risk and low potential damage; and that the structure was 15 m high with a storage volume of 580,000 m³.
Whilst this was a comparatively contained failure, it once again highlights the utterly unacceptable rate of tailings dam collapses.
Planet Team (2019). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/.