Lessons we can draw from the Samarco tailings dam failure

Damage from the Fundão Tailings Dam failure. Copyright: Romerito Pontes. Creative Commons License

Damage from the Fundão Tailings Dam failure. Copyright: Romerito Pontes.  Creative Commons License

First of all, it is good to be back with you blogging again. As some of you might know, I spent most of 2015 and the first seven months of 2016 as an Academic Mining Engineering Fellow at the US Securities & Exchange Commission (SEC). Given the plethora of ethics rules that apply to federal government employees, I decided to completely shut down Sphinx Mining Systems while I worked for the SEC. I thoroughly enjoyed my work with the SEC. But I’m glad to be back at Missouri S&T teaching and doing research and to be able to connect with industry through my consulting practice. Which also means I can now use this blog to express some of the things on my mind in relation to our industry.

This week, I read about the release of the report by the Fundão Tailings Dam Review Panel, a panel formed by the owners of Samarco, BHP and Vale, to investigate the cause of the tailings dam failure that caused 19 deaths and widespread damage to property. The owners of Samarco say they have set aside US$1.3 billion to cover liabilities that will result from this disaster. Whether or not the amount is enough, it is clear this failure will cost a lot of money.

The report and the presentation by the panel members blame seismic activity for initiating liquefaction leading to the failure. But, the panel also point out that the dam was already in progressive failure caused by a series of events. Implementation of the initial design encountered challenges. In particular the original drainage system failed leading engineers to come up with an alternate plan to drain the part of the dam between the two dykes. As we now know from the panel’s report, the drainage system they came up with was flawed. It is easy, in hindsight, to see the plan they came up with is flawed. It was obvious to me when I saw the plan (as presented by the panel) that it would not work. But we can all be experts in hindsight and should be careful how we judge these engineers.

However, the lesson I think all of us engineers in the industry can learn is that we should take care when we make modifications to mine plans and designs. Part of fundamental engineering practice relating to implementation of engineering plans is monitoring the plan to see if it is performing as intended. And when we identify variances between the design and actual performance, it is our job to address it by going through the design process again to design the modification. However, it appears we sometimes rush into fixes without the same rigor that we used in the initial design stage. Sometimes, no rigor at all is applied. Some “field” engineers have a tendency to devalue engineering design. And there is a tendency to just do things without the required engineering analysis. In fact, I have met some engineers like that who actually believe taking the time to do such analysis is a waste of time. These folks tend to think the solution to problems is just obvious to them. Hopefully, we can learn from Samarco that there are 1.3 billion reasons to take the time to evaluate the solutions we propose in response to observed variances in design performance.