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Tailings dams design and experience

Lately several tailings dam failures rocked the mining world. Despite the relative high frequency of these events we have heard engineers qualify the failures as “one in a million”, “extremely rare” or even “black swans”. Today we want to discuss a few concepts on tailings dams design and experience. In particular, we will focus on some disconcerting qualifiers like the ones we just cited above. For example, given the experience of tailings dams catastrophic failures  resulting from combinations of various…

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Not all risk assessments are created equal

The UNEP “Mine tailings storage: safety is no accident” report asks mining companies to make environmental and human safety a priority. To ensure mining companies meet that result in management actions and ground operations, a residual risk assessment should be performed. For clarity, residual risk assessments are those that intervene after mitigations or critical controls.  However not all risk assessments are created equal so let’s explore the differences. What are the requirements for a good risk assessment? Risk assessments are…

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Tables of Risk comparisons

Most tables of risk comparisons in the literature contain a mix of risks characterized by different levels of uncertainty. In addition, most risk comparisons in those tables offer only single number risk estimates, with no range or error term. For risks such as driving, where fatalities can be counted on large samples, the number is likely to be reliable, at least in some countries. However, even if the risk comparison data are carefully and accurately reported, they can be misleading.…

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Catastrophic failures forensic analyses

Catastrophic failures forensic analyses are, most of the time, left in the hand of experiences engineers. At least, that’s the case for tailings dams failures and other catastrophes like major infrastructural accidents and for instance, aviation. Are we sure that is the best way? Normalization of deviance, management and decision-making are oftentimes ingredients of the catastrophic failure buildup, not only “engineering”. So, we dare to say, Independent Panels should include social scientists. They seem to be the most qualified to…

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Of Human and Dams Health

Someone asked us to do a ELI5 tailings dam failure (i.e. Explain me Like I am 5, aka explain in layman’s term what are the problem in the management of dams). We find the similarities on common traits of Human and Dams Health particularly striking and hope it helps people to understand the missing pieces. Human Health Human health is a complex field. Numerous factors (Key performance Indicators) may generate diseases which provoke failure modes, such as: Heart issues Lungs…

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Quantifying Tailings Dam Risks at MIRA

Quantifying Tailings Dam Risks at MIRA (Mining Insurance and Risk Association) one hour session took place on June 11th 2020. The talk presented a comprehensive approach to address how to quantify and prioritize tailings dam risks, especially in the context of large dams’ inventories. In this blogpost we summarize the Q/A session that followed the talk, classified by theme. The full talk is viewable on Youtube    At the end we present a synthesis before some closing remarks. Understanding geology and…

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Uncertainties in risk assessments

Uncertainties in risk assessments derive from data, model and system uncertainties. In addition, these mix with soft issues like language and cultural barriers. There are for example languages where the term “risk” simply does not exist, like in Japanese. The closest word Japanese have in their language is 危険 (kiken). It means danger, risk, hazard, peril, jeopardy, pitfall all in one. Thus it fails to grasp the specific concept of risk and generates confusion. This is the reason they had…

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Distinguishing knowledge in risk assessment and risk-informed decision making

Distinguishing knowledge in risk assessment and risk-informed decision making is paramount and this post shows an example. Once upon a time we were studying large Alpine landslides in the Alps. We were working in a Swiss Federal Research Project.  We were members of a multidisciplinary team encompassing geologists, hydro-geologists, monitoring specialists and ourselves as geotechnical engineers and risk (hazard) specialists. The research project focused on landslides prone areas characterized by “continuous” movement. For those slopes, failure is a brutal and…

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