From the news here:
"The images that have just been shown by Rede Globo make it very clear that it was a process of infiltration of liquid - water or dense mud - which overturned Vale 's tailings dam at Brumadinho.
Not an overflow, not a crack in the embankment, but an immense stain of moisture that, for a few seconds, appears right at the base of the dam, which is 40 years from the beginning of its construction. Then its edges saw a splash of mud, fed by the "descent" of the copro dam, similar to one of the "implosions" of buildings we have seen so many times.
Almost at the center of the building, the impression is that a sheet of water or very dense tailings, underground (the dam was dry on top, with vegetation, including small trees) liquefied the earth's reservoir.
The phenomenon seems to be the same in another point, to the right of the one who looks at it, approximately on the same level as the first, although both are practically simultaneous, because everything is very fast.
It was not, therefore, a rapid accumulation of water, but a process of slow and progressive accumulation.
How such an unstable and potentially disastrous layer has formed without the detection instruments not being signaled seems to be the "mystery".
The so-called piezometers, devices used to monitor dams, measure the levels of water accumulation in deep sections of the dam and did not detect them. Were they at this depth corresponding to ancient periods? Or were they neglected because the dam had been abandoned for some time?
The video that records the fall of the dam has the equivalent importance to the "black box" of crashed airplanes.
We know what happened, we do not know why it happened and because of who happened.
And if they want to hold anyone accountable. "
Pedro Rezende
Vespasiano, MG
Minas Gerais Railways
