Innovation in Dams Screening Level Risk Assessment

For some reasons Innovation in Dams Screening Level Risk Assessment feels like an oxymoron.

At each new accident organization like MAC produce a new edition of their manuals, for example Developing an Operation, Maintenance, and Surveillance Manual for Tailings and Water Management. The new editions generally represent a strengthening of some rules, but the result is always very similar to the prior edition, does not address systemic failure to properly evaluate risks of old and new facilities.

Let’s tackle fundamental questions in dams risk assessment

Various authors have summarized lessons learned from recent tailings dam failures over the last decade.

The absence of risk assessment, or designs paired with fuzzy and misleading risk assessment approaches, are considered by some as an important factor related to poor risk awareness. Indeed, commonly used risk matrices (e.g. Failure Modes and Effects Analysis (FMEA), Probability Impact Graphs (PIGs), etc.) often assign identical ratings to quantitatively different risks, a phenomenon often referred to as “range compression” and can mistakenly assign higher qualitative ratings to quantitatively smaller risks and vice versa (risk matrices problems). Additionally, assessors often censor and bias risk assessments towards “credible events”.  However, history has shown that major failures are often due to “incredible events”. In some cases, also, to a long chain of apparently benign events that occur due to normalization of deviance. Even though the public does not necessarily clearly understand those fallacies a growing distrust is created, generating widespread controversy and opposition to the project (Oboni et al., 2013).

Innovation in Dams Screening Level Risk Assessment requires replacing obsolete ad misleading common practices with proven approaches. These should avoid the well known pitfalls of the former.

What are the steps to Innovation in Dams Screening Level Risk Assessment?

In the twenty-first century:

• the use of Factor of Safety should be once and for all proscribed;
• no designer should allow himself or herself to perform the risk assessment for his or her own design;
• no cost estimate should deliver deterministic, one-number results;
• risk assessments should be transparent.
• The public has the right to see the risk assessments results.

What do we do to perform those steps?

 At Riskope we have been publishing extensively the results of our research.

This year we will go several step forward: our paper at ICOLD2019, in cooperation with MDA will discuss among other points how to integrate Space Observation in dams screening risk assessment and portfolio prioritization.

In late Summer we will publish our book on Tailings Dams Risk Management. It is the result of twenty years of development. It presents the theory and gives a wide space to the treatment of a case history. The case history is based on real-life dams we have recently assessed.

Tagged with: B.C. Tailings Dam Failure Frequency, tailings, Tailings Facilities

Category: Consequences, Hazard, Probabilities, Risk analysis, Risk management