Tailings Dams in Brazil

Past, present, and future risks associated with mining dams

Mining Activity in Brazil

Map of colonial roads to transport gold and diamonds in Brazil. Courtesy of Angela Ricciardi  via Pinterest  

Mining has been an important economic activity in Brazil since the discovery of rich mineral regions during colonial times. Portuguese settlers first discovered reserves of gold in the state of Minas Gerais in 1693, and later diamonds in 1729. Since then, mining has always been an important aspect of the Brazilian economy, especially in the state of Minas Gerais, which in translation to English means general mines.

Currently, Brazilian mining activities are centered on iron ore extraction, being the 2nd largest exporter. The country is also prominent in the extraction of copper, gold, aluminum, manganese, tin, niobium, and nickel.

Gemstones are also explored in the country, with lead exports being amethyst, topaz, agate, tourmaline, emerald, aquamarine, garnet, and opal.

Currently, industrial mining in the country resorts to tailing dams to dispose of mining byproducts that do not serve any purpose in the commercial chain or have high levels of toxicity.


Dam Construction

Tailings dams diagrams representing forms of dam construction for the disposal of industrial mining byprouct. Image 1 (left) is a courtesy of  Kym Lesley Morton , and image 2 (right) retrieved from  WISE Uranium Project  

Diagram showing the different approaches for the construction of tailings dams. Courtesy of  The Wall Street Journal  and W ISE Uranium Project 

Previous Accidents

With the accumulation of byproduct deposits and climate and seismic variations, dams can failure, leading to the breakage of security walls and spill of dam contents. Tailings dams are more susceptible to accidents since they are not built of concrete. The dykes are often built out of dense compacted mud.

Mariana Dam failure (2015) Image 1 (left) shows the contaminated river stream flowing into the Atlantic Ocean. Image 2 shows the village of Bento Rodrigues after the event. Image 3 (right) shows the area covered by the flow of byproducts. Courtesy of  IUCN Portal , CNES 2015 Distribution Airbus DS, and TV Senado.

Brumadinho dam failure (2019). Retrieved from the  Wall Street Journal  

Brumadinho directly affected area

Scene presentation on regions where dams in risk of failure are located in the state of Minas Gerais. The scene viewer allow us to understand better the countours of the land and possible routes for mudflow.

Map of colonial roads to transport gold and diamonds in Brazil. Courtesy of Angela Ricciardi  via Pinterest  

Diagram showing the different approaches for the construction of tailings dams. Courtesy of  The Wall Street Journal  and W ISE Uranium Project