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Tailings dams knowledge base creation

Tailings dams knowledge base creation is about how to acquire the information needed to perform well documented risk assessments. Of course, there are many possible ways to create the necessary knowledge-base for a risk assessment that is compliant with the new Global standard. Today we will discuss a few possible ways to do so at a high-level.At Riskope we passionately believe that only a blending of these approaches is capable of bringing the answers needed for high quality risk assessments…

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SLM and the Probability of failure of a tailings dam

SLM and the probability of failure of a tailings dam goes back 35 years.  A paper entitled “Probability and Risk of Slope Failure” (Silva et al., 2008) proposed using quantification of expert judgement.  That is a subjective/semi-empirical probability evaluation as a practical alternative for determining probability of slope failure. We call this approach SLM, using the initials of the authors. SLM culminates with semi-empirical relationships between Factor of Safety -FoS- and probability of failure -pf-. That relationship allows to estimate…

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Codes, resilience and climate change

Many clients are dealing with a conundrum at the cross between codes, resilience and climate change. Solving it is paramount for tactical and strategic planning purposes. Code compliance is not synonymous with resilience When facing good-old hazards that are becoming more frequent and more intense, perhaps due to climate change, it is easy to realize that code compliance becomes meaningless. Indeed, codes work for the “good old way”, both in terms of resilience and frequency. A code compliant solution may…

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Credible events and black swans

We have discussed credible events and black swans several times in this blog, but this time it is different. We do have a real black swan event and we can show it is incredible! 31st  December 2019 to end of February I can still recall champagne popping on December 31st 2019.  Everyone was merry, the expectations for an incredible 2020, a bissextile year on top of that, were flamboyant. Yes, pun intended. Flying to Italy from Brazil on January 23rd …

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Dams Failure modes and catastrophic failures

Today we explore the relationship between Failure modes and catastrophic failures. Catastrophic failure of tailings dam and its water management structures are the likely result of the failure of a number of essential components or any combination of states. We purposely use a different terminology from failure modes because they explain how the dam can fail, but not why. If we look at past events, hydro dams and tailings dam are similar as, for example Oroville and Fundao did fail…

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Strategic operational and tactical planning for tailings hydro dams

We are learning that structural integrity of hydro dams is also becoming an issue. Thus, similarly to tailings dams, we need a strategic operational and tactical planning for tailings hydro dams! Karl Terzaghi, American Society of Civil Engineers, “Terzaghi Lectures, 1974-1982,” American Society of Civil Engineers (1986) ISBN 0-87262-532-X. proposed that a dam rating system should provide ALL of the following: A logical framework for rating the relative safety of a dam Allow for the use of judgment and experience…

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Dam risks informational gap

Dam risks informational gap impacts to a certain extent all dams: hydro, tailings and finally, toxic dumps. There are thousands of active dams around the world significantly different because of: age, function, materials, construction style and care, maintenance care and finally “behavior” or performance. Oroville dam was one of those, like other recent mining catastrophes and the Michigan failures. What do all dams have in common? Dams are all exposed to hazards, e.g. natural, man-made such as excess of confidence,…

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Comparison of ORE2_Tailings estimated dam failure probabilities

The comparison of ORE2_Tailings estimated dam failure probabilities is an important element of Riskope continued commitment to test the validity of the approach. Quantitative risk assessment in tailings One can perform a Quantitative Risk Assessments (QRA) using various methods. Indeed, for tailings dam risks, they all consist in evaluating the: probability of failure of the dam generated by various pertinent hazards, potential consequences of a dam system collapse (failure) and finally the risk. The technical and mathematical tools for performing…

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