By Clara Clemente Langevin
The Brazilian State of Minas Gerais has always been considered the heartland of Brazil, evoking images of rural hospitality, hearty food, and rococo colonial architecture nestled between beautiful mountains and rolling hills. Underneath its lush geography is what really keeps Minas Gerais going forward. Literally named “General Mines,” the region was first colonized by the Portuguese for its gold and precious minerals. Now, its main economic activity is the extraction of iron ore and minerals, where it produces over 160 million tons a year of iron ore and is responsible for 53 percent of Brazil’s metal production. However, an uptick in mining-related tragedies, particularly tailing dam failures is threatening both the large portion of the Mineiro population that works in the mining sector and the precious ecology in the surrounding area.
On January 25th, a tailings dam in the Córrego do Feijão iron ore mine near the small town of Brumandinho, Minas Gerais collapsed. A wave of mud flooded the region covering houses and businesses, and inevitably people and animals. One month after the incident, the official death toll is at 186 individuals, although over a hundred are still missing. Many of the victims were employees and subcontractors of the mine’s owner, mining giant Vale S.A. Now that the mud has solidified, the consensus among first responders is that it is extremely unlikely that any more survivors will be recovered from the mud.
This awful tragedy in Brumadinho is prefaced by a similar incident three and a half years ago, when the mud from a failed mine tailing dam completely overtook the village of Bento Rodrigues near the city of Mariana, Minas Gerais. This incident killed 19 people and had an enormous ecological impact — around 60 million cubic meters of iron waste flowed into the Doce River, which then found its way into the Atlantic Ocean. Scientists say that the thick orange sediment full of runoff from the iron ore will alter the course of streams as it hardens, reduce oxygen levels in the water, and diminish the fertility of riverbanks and farmland where floodwater passed. This mine was a joint venture of Vale S.A. with the Anglo-Australian conglomerate BHP.
Mine tailing dams are the most common method of waste disposal for mining enterprises. The extraction of iron ore requires water to grind and process the mineral. The resulting waste takes the form of a slurry with several mineral particles, often toxic. These “tailings” are permanently stored in a reservoir that is held in place by a dam. Most tailings dams are upstream dams which require the least amount of space and materials to store the slurry, and these dams are constructed and raised in stages. Upstream dams, like the one in Brumadinho, are the cheapest and riskiest structures.
The Columbia Water Center’s 2017 report on Assessing the Risks of Mine Tailing Dam Failures gives recommendations on understanding and assessing the risk of tailing dam failures. The report points out that the majority of mine tailing dam failures are a result of faulty design or construction, poor management, extreme events, or a combination of these factors. The researchers recommend creating an inventory of existing tailings dams worldwide, including location, construction method, age, height, volume, activity, contents, and downstream surroundings. The researchers also developed a hazard rating index to analyze dangers to people and ecosystems downstream in the event of a failure, and to inform investors about potential risks of tailings dams.
In terms of the construction and use of tailings dams, the Columbia Water Center report recommends the following:
- Implement a risk assessment program during the design and operation of tailings dams. This means evaluating what could go wrong, how likely those hazards are to occur, and how bad the effects would be.
- Ensure that an independent review board is involved in the design process.
- Complement external audits and compliance to best practices with new monitoring technologies, such as using satellite and aerial images to track changes in the tailings dams.
- Calculate cost increases for additional risk assessment and oversight. When companies don’t understand the potential financial benefits of avoiding a tailings dam failure in the long term, it makes it difficult to decide whether investing in better monitoring and management practices is worth it.
Since this is the second time in less than four years that a Vale-owned tailings dam has failed, public opinion has been quick to condemn the mining giant and criminal investigations are currently underway. Vale had previously denied having upstream tailing dams before the Brumadinho incident. Vale now has a considerable amount of its assets frozen in anticipation of its pending criminal investigation. In addition, the families of injured, dead or missing victims are expected to file suit for claims, since Vale is financially responsible for those deaths under the Brazilian Federal Constitution.
Unfortunately, criminal investigations are just a band-aid solution, because without substantial changes to mining regulation and industry practices, these kinds of accidents will become more and more common.
The outlook for regulations that will incorporate the Columbia Water Center’s best practices are slim. Brazil has recently banned upstream dams, but this is not enough to ensure that these kinds of accidents won’t happen again. Recently elected President Jair Bolsonaro has endorsed through his finance minister Paulo Guedes the deregulation of the Brazilian private sector, so it is unlikely that more firm regulations on mining companies will be imposed. In the aftermath of the incident in Mariana a few years ago, the more progressive administration of Dilma Rousseff also failed to pass substantial regulations.
The latest estimates suggest that there are more than 15,000 mine tailings dams worldwide, the World Mine Tailings Failures organization predicts that 19 similar accidents could happen throughout the world between 2018 and 2027. So while politicians delay taking action, another tragedy could be right around the corner.
Clara Langevin is a Master’s in Public Administration in Development Practice candidate at Columbia University’s School of International and Public Affairs (SIPA), and is currently an intern at the Earth Institute. Before starting at SIPA, Clara worked at the International Telecommunications Satellite Organization in Washington, D.C., where she assisted with various information and communications technology-related projects, ranging from rural broadband programs to emergency connectivity initiatives. She is a dual U.S.-Brazil citizen, and is a member of both the Latin American Student Association and Brazil Talk.