Not all risk assessments are created equal
Jul 22nd, 2020
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 prepared using various methods of modeling, analysis, and evaluation. Various types of uncertainties afflict them. In general, uncertainties may be attributable to a number of factors like, for example:
Why classical approaches fail?
Classical failure modes approach (FMEA) describe how a system fails, for example how a dam fails, but not why it fails.
In addition, failure modes analyses oftentimes leave aside:
Risk assessments uncertainties and updates
The risks generated by a dam stem from uncertainties encountered during the:
- course of project development, from project inception,
- planning and conceptual design through site investigations, and
- detailed design and into closure and post-closure.
It is important, therefore, to keep in mind that risk analysis should be continuously reviewed and updated. That is necessary as:
- more data become available on the considered system,
- conditions around it change and
- perhaps even design criteria evolve over time.
Some methodologies will lead to paralysis by analysis
Integrated methodologies like for example “NASA PRA” may be too detailed and too costly to be deployed for a large dam inventory.
Using a methodology allowing:
- the utilization of preliminary dam safety visual inspection checklists to prioritize portfolios, inform decision-makers, and
- to swiftly guide mitigation plans
is paramount. Of course, the amount of preliminary information and required review effort will vary from site to site. The effort also depends on existing monitoring programs and as a function of possible backward space-observation analyses.
Updatability and aggregation are paramount
After a dam safety audit and comprehensive dam safety reviews is completed, the dashboard and risk priorizations is expected to be updated. Indeed, from a dam owner perspective, the result of one single dam must be put in relation with the overall portfolio. Throwing CAPEX at one dam and neglecting the others may prove to be counterproductive and expose the owner to unwanted liabilities.
A documentation effort that will result from a good risk assessment is the risk register. The risk register of a rational risk assessment should allow bottom-up aggregation of risks delivering the risk information required for:
- decision-making support and
- insurance, risk transfer and
- other planning purposes
while explicitly considering the uncertainties in both pf and C, and accountability.
Not all risk assessments are created equal closing remarks
Despite the best intentions, many risk assessments and management efforts fail. There are multiple reasons for that which can be summarized by “not all risk assessments are equal”.
The risk assessment methodology has to be compatible with the system: single dam? Multiple dams portfolio? Entire mining operation? The risk assessment has to avoid common pitfalls of classic FMEA based qualitative or indexed approaches, be convergent, updatable, drillable.
It has to support the owner in making better decisions. The approach has to preserve and build value while preserving and fostering CSR and SLO.
Tagged with: FMEA, Mine tailings storage: safety is no accident, natural hazard, PRA (Probabilitic Risk Assessments), residual risk assessment, RIDM, Risk Assessment, UNEP
Category: Consequences, Hazard, Mitigations, Optimum Risk Estimates, ORE2_Tailings, Risk analysis, Risk management