It is no secret that mining has a bad environmental rap. Often, mining companies try to dispel this view by promoting the sustainable measures they take to mitigate their environmental impact to the lowest it can be. While far from perfect, mining has drastically improved its environmental footprint in the last 100 years. Even the last 50 years have seen constant innovation to do better by the communities and ecosystems around which mines are built. One unavoidable aspect of mining, however, which has yet to be solved, is the aspect of tailings.
Tailings are the result of the processing of mined rock. Usually finely milled, the tailings are mixed with water to form a sort of sludge which can be contained somewhere as the particulate matter settles out of solution. One major issue with tailings is that it is often very concentrated in chemicals due to the breakdown of minerals during milling and the treatment with other chemicals to remove the metal being mined. Back in the days before regulations, mines would simply dump this stuff in their backyards causing all sorts of problems to the flora, fauna, and water systems which we are still trying to deal with to this day. Now, we keep tailings enclosed in tailings dams, preventing it from mixing with surface or groundwater systems. Designing proper tailings dams is one of the most important aspects of mining today.
It becomes all the more shocking then, when you hear about a disaster on the scale of the Vale tailings dam failure which occurred on January 25 in Brazil. The dam burst and sent a torrent of thick, fast-flowing liquid sludge pouring through the landscape. Along the destruction path was the administrative building in which 100 employees were having lunch. The warning system couldn’t give them enough time to leave the building and get to safety. 110 people are now confirmed dead and another 238 victims are still missing, most of whom are employees of the mine. This disaster is the most deadly mine failure in Brazil’s history.
Vale, the company who owns the Brumadinho mine, is one of the world’s top iron producers. It claims to still not know the cause of the failure, although the dam was built in the 1970s There has apparently been an attempt, since the last major tailings dam failure in Brazil in 2015, to ban upstream tailings dams as an obsolete way to store the mine waste. Evidently, there has been pushback against this measure, which would cost companies who use these dams to store waste, a lot of money.
What can the takeaway be here? Well evidently after two of the worst tailings disasters in Brazil’s history occurring in such a short span of time, causing unspeakable environmental damage and loss of life, the government is going to try pushing through legislation to ensure failures are caught before they happen and prevented. When this will be implemented, if ever, is anyone’s guess. The mine at Brumadinho has a second dam which will now be closely monitored for any signs of rupture or dam weakness. The takeaway cannot be never to mine again, but what can we as university students do to make sure when we enter the workforce that we do not contribute to willful ignorance of dangerous situations. As engineers, one day we will have the good of the public on our shoulders and like the iron rings we wear to symbolize the failed bridge in Quebec, we can’t forget that the work we do can have real-world consequences even decades after it is done. As the engineers of the future, it is up to us try to find better ways of doing things than the generation that came before us.