A catastrophic tailings dam failure at an iron-ore mine in Brazil has led to multiple fatalities and injuries, according to multiple news outlets. Some agencies have reported as high as 17 deaths, though most outlets have generally revised downward now and indicated that many more may be affected. Access to Bento Rodrigues, a village adjacent to the Samarco mine operation, which is owned by BHP Billiton Ltd and Vale SA, has been compromised by the significant volume waste that has spilled.
The dam burst on Thursday afternoon, flooding the town with iron-ore tailings and polluted water. The site is one of the world’s biggest iron-ore producers for the steel industry.
Brazil-based UOL has shared images of the damage from multiple sources. More aerial views can be seen in the news report at the end of this story.
WERE GEOSYNTHETICS INVOLVED?
It’s much too early to tell why the tailings dam failed, and likely a combination of factors are involved. There are some indications that precipitation and flooding may have been experienced in the area prior to the failure.
In the geosynthetics industry, of course, many are questioning immediately if geosynthetic technologies had even been used in the design.
The absence of geosynthetic support in similar structures has contributed to multiple, significant engineering failures around the world over the past decade, include the Kingston, Tennessee coal ash storage failure (2008); the alumina sludge spill in Hungary (2010); and the Mt. Polley Mine embankment collapse in British Columbia, Canada (2014).
RELATED: HOW COAL ASH FAILURE CHANGED US REGULATIONS
Brazil, and South American in general, has experienced various levels of tailings storage facility failures. Multiple workers were killed in a tailings collapse in 2014 at Itabirite, for example, and the 2007 collapse at the Mineração Rio Pomba Cataguases facility displaced thousands of people from the cities Miraí and Muriaé.
A paper published in 2009 at a conference in Canada indicated that tailings failures typical increase during periods of lower metals prices on the world market. That is exactly the situation being experienced today.
It isn’t clear yet if the Samarco site’s tailings dam had any geosynthetic reinforcement or lining system. An engineer affiliated through his employer with the operation spoke in October at an IGS Brasil workshop on geotechnical engineering and geosynthetics in mining; but, nothing specific to the site in question was related.
IGS Brasil is a chapter of the International Geosynthetics Society (IGS).
Furthermore, an engineer who works within Brazil’s geosynthetics industry and who has visited this site did not, offhand, recall geosynthetics in this part of the operation. It may have been a conventional earthen structure.
If that is the case, it would seem to follow how other sites have experienced failures through precipitation-induced erosion and collapse of earthen embankments, poor drainage design, overloading of tailings, or a combination of these and related factors.
Geosynthetics are engineered to provide solutions to these types of scenarios.
A Samarco engineer was even a co-author on a paper about failure potential at Brazil’s biggest geotechnical engineering conference, Combramseg, in 2010. The research (“Liquefação Estática em Depósitos de Rejeitos de Mineração” [PDF] via Combramseg’s open library) was authored by Lorena Romã Penna, Waldyr Lopes de Oliveira Filho, Luiz Gonzaga de Araújo, and Francisco Eduardo Almeida. In their study on the potential for static liquefaction in iron waste, they found, using a test site—without geosynthetics—sand boils, cracking, and saturation.
Again, nothing is known at this time about the specific section where failure has occurred. The foremost interest is in emergency response at this stage for the people of Bento Rodrigues.
