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The Truth About Dams in Minas Gerais, Brazil


There are multiple kind of dams in Brazil. Some are used to hold water, some to generate energy and some to hold industrial and mining waste. The variety of dams reflect their conditions: many dams are in poor shape while some maintain low risk to the environment and the people living near it.

The mining waste dams are notorious for their relevant environmental impact. Even though technology has progressed, it is known that companies in the states of Minas Gerais in Brazil prefer not to employ the new findings. The reason is the same of always: to keep their profits as high as possible.

Brazil itself lacks a system that has deep information on these dams. When a catastrophe happens, like the ones in Brumadinho and Mariana, the government officials feel unprepared and have to collect information on the spot to help the people affected by the spilling.

The state of Minas Gerais does have a system for the registration of dams and their conditions. When the requirements are not met in the reports, the officials communicate the dam owners what they need to do in order to keep their dams safe to the environment. 

The following study from 2008 uses a methodology proposed by Menescal et al in 2001 which was adapted for mining waste dams. The results are as follows:


  • ·       Most of the dams with high hazard potentials were the ones with the lowest retention volumes of waste;

  • ·       The most common method for the growth of the dams is the upstream one, which is also the cheapest of all of them;

  • ·       Most of the dams presented adequate (yet still dangerous given their volumes of retention and locations in the region) results of percolation, deformation and deterioration;

  • ·    Over 60% of the dams hold high volumes of waste;

  • ·    About 76% of the dams have population spots downstream;

  • ·    About 30% of the dams need extra examination and attention from the owners and authorities;
  •     About 48% of the dams in working conditions showed a high hazard potential and 51% had worse results;
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