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| Image by The Wall Street Journal |
For those who, like me, do not know much about tailings dams, I tried to
briefly explain here, in more intelligible terms, what I read and understood about this, following the
disaster recently occurred in Brazil. I have placed links supporting this text
at the bottom of the page.
The construction of these
tailings dams is different from that of hydroelectric dams. They raise the
containment barrier of the reservoir to increase its capacity as the operation
procedures of the mine progress. These parts added to the barrier in order to make it higher are made
using the reject material itself, in more condensed portions. This seems to me
something extremely primitive in terms of construction.
From what I read, these collapsed dams in the state of Minas Gerais,
Brazil, had received
permission from the responsible agencies to increase their capacities more and
more; however, there are doubts
about the safety of the structure. In addition to all environmental damage,
there were people living near these mines. An absurdity! Greed always leads to
misfortune!
A similar case occurred here in Canada, in 2014, but fortunately no human loss was recorded.
The affected area, however, has been contaminated with tailings, and it is not
possible to predict how long it will take for a complete recovery or if this
will happen. One of the cleanest lakes on the planet has become
"dirty", with restrictions on use.
The mining dam collapse
happened in British Columbia at the Mount Polley mine. There was a complete
catastrophic failure; everyone had said it would not happen. The mine returned
in function in 2017 because the economy of the region needed it; the structure
has been strengthened. But the operations of the mine will stop again in 2019
due to economic decline of the company.
Why are tailings dams not built like water retention dams? It may be my ignorance, but I think all of this is
not correct.
If the answer is because
they do not know in advance how much ore could be exploited, then the necessary
dimensions would be unpredictable... I see a positive aspect in the
construction of a dam with previously established limits, to limit
exploitation, to a certain extent, disturbing less the natural environment.
If interested parties do not
agree to build a dam that may be too large for a mine that would ultimately not
give so much flow, that is to say the cost/benefit ratio might not be
worth it, then let them build with the traditional method, raising the dam in succession throughout the life of the mine, but never near inhabited areas. How awful!!! If it's close
to homes, it will require a stronger construction than the currently
recommended!
Rules and laws must be changed!
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