The Brazilian Federal Police said Vale’s vertical drilling works led the Brumadinho dam to collapse, according to an expert report presented late last week.
The police report said Vale commenced drilling works in a critical area of the Brumadinho dam just days before the structure collapsed. The structure’s most critical point was hit with the drilling works at a depth of 68 meters. As the drilling works reached that specific section of the structure, it generated a wave of liquefaction.
The report said the perforation “induced” a water pressure at a very sensitive point of the dam, which caused it to double its pressure in that very specific part of the structure. As a result, this sensitive section of the dam collapsed due to liquefaction. The liquefaction was then extended to all the dam structure.