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The causes of the 2015 Mariana tragedy

The causes of the 2015 Mariana tragedy - The Brazilian Report
Rescue teams in the Mariana region

This series about the Mariana disaster was originally published by Brio, in Portuguese. It was translated by Gustavo Ribeiro and edited by Christine Bootes


Chapter 3: The Origins of the Mariana Disaster

Forty years prior to the devastation of the Mariana Region, government negligence opened a breach that would result, decades later, in the collapse of the dam – Brazil’s worst environmental disaster, ever. Dozens of authorities had the opportunity to disarm that ticking time bomb but systematically failed to do so.

During the 1970s, Brazil was going at full steam. The dictatorial government of General Ernesto Geisel (1974-1979) wanted to place the country, at all costs, on the world map of industrial development to help dig Brazil out of the severe economic crisis that had hit us back in the 1960s. His predecessor, General Emílio Médici (1969-1974) had already set in motion some projects – they became known as the “pharaonic projects” – which included a road crossing the Amazon.

Back then, the Constitution and the Federal Mining Code – both approved in 1967— legitimized the “first come, first served” logic regarding concessions to the exploitation of Brazil’s mineral resources. The legal framework at the time guaranteed the rights to extract from mineral deposits to the first company to request it from the National Department of Mineral Production (DNPM).

Environmental hazards were hardly a priority during these decades. At that time, the country didn’t even have a legal definition of the word “environment.” The Federal Mining Code was limited to punishing mining companies that caused “damages to third parties” as a result of their activities. It also demanded the “safety and sanitation of the houses in the companies’ premises,” and forbade the pollution of air and water.

If a company could prove that undertaking mining would be economically viable, then it was almost sure to obtain the license. The only obligation would be paying for the land – when necessary. Simple as that. “At the time, the focus was on stimulating Brazilian growth, and environmental questions were not a priority,” explains Valmor Bremm, a lawyer specialized in mining law.

That loose regulation allowed Samarco to set up business in a region between the cities of Mariana and Ouro Preto, and to build a residue dam in a district of Mariana, just 11km away from the small agglomeration of Bento Rodrigues. This is what mining experts refer to as a “geographic fatality,” explains Alberto Fonseca, a professor and researcher in mining and environmental issues at the Federal University of Ouro Preto. When mineral beds are concentrated in a specific region, the exploitation must occur in that same area or else it won’t be economically viable.

When Samarco came to the region, it brought thousands of new jobs – the kind of development that the dictatorship craved so much. Instead of the traditional use of trucks to transport iron ore, Samarco was a pioneer, introducing the use of pipelines to drain its production. This came with many advantages, for sure, including a reduction in carbon dioxide emissions (CO2, a greenhouse effect gas). But it consumes huge quantities of water, essential for the iron ore to slide inside the pipelines in the form of a sticky mud.

The exploitation process also produces huge amounts of residues, a sandy mud with no commercial value. As Samarco increased its production, it also increased the amount of residue it had to deal with – hence the creation of large dams for storage. The company decided to build the gigantic Germano dam, with the capacity for holding 200 billion liters of residue. The singing of local birds was abruptly replaced with the noises of machinery, disturbing the neighboring populations without any regard.

“We were never asked about it,”...

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