Cobriza, Peru tailings dam failure

Cobriza, Peru tailings dam failure

Jul 24th, 2019

Cobriza, Peru tailings dam failure occurred at Cobriza in Peru on July 10th   2019.  Cobriza is a copper mine. Reportedly “the concentrator was operated at a rate quite below its capacity due to lack of mine ore and lately (2016 and 2017) due to lack of capacity in the tailings dam“.  The plant is also subject to a highly controversial liquidation. Media invoke poor management as a cause of the failure.

Cobriza, Peru tailings dam failure

Google Earth image of the Cobriza mine tailings in Peru.

The failed tailings facility has a surface of about 500 m x 300 m.

The tailings runout has reportedly generated a serious pollution incident in the Rio MantaroThere are fears that a stretch of the river extending for 375 km has been contaminated with cyanide.  

Fighting information pollution with Risk informed decision making

We have not heard of any casualties resulting from this accident. Although the Peruvian media describe the environmental damage in catastrophic terms, we have not located any rational description of the damage to date. This is not surprising. Indeed, looking at we see that many past tailings  failures have unknown consequences and there is no uniform consequence metric in the industry 

Additionally, we followed and even participated in a thread on Linkedin started by a post stating: “Filtered tailings stack failed in Peru”.

We started by writing that Riskope’s courses have been teaching that filtered tailings stacks are not risk free. We even gave examples of projects with very real «new» risks.

In our new book, Tailings Dam Management for the Twenty-First Century; What Mining Companies Need to Know and Do to Thrive in Our Complex World we discuss management issues. Because modern risk assessments should be convergent and include all hazards, including those generated by design, regulations and management.

Risk informed decision making amid news and fake news

Now, beside the fact we have good and proven reasons to state the above, we soon learned that the failied TSF was likely a drying cell and not a filtered tailings facility.

Indeed, it was stated by partakers to the thread that Cobriza does not actually filter its tailings. We don’t want to speculate because at this time we do not really know for sure.

No one invoked the meteorological situation. Indeed May, June and July are among the driest months in Cobriza. So, was it a sunny day dam break?

Were there any seismic events? Even of small entity?

The basic level of information is insufficient to allow any preliminary pre-failure risk assessment of any kind, contrary to what occurred for Mount Polley, Samarco and others as we explain in Tailings Dam Management for the Twenty-First Century.

Cobriza, Peru tailings dam failure explanations?

In this day and age of immediate twitter flashes, blogs and self-made, unverified journalism it becomes extremely difficult to get a clear image of reality. Too much unreliable information is simply just bad information. Bad information hide truth and mislead the public, allowing each one to take home what they want to hear.

Thus, based on the contradictory and uncertain nature of the available information, we do not think it is possible to formulate even the most preliminary hypothesis on the causes of this failure. The mining industry should have a uniform tailings dam failure consequence metric, a mine waste classification,  and adopt a failure reporting policy with proper communication channels.

The file is open and as soon as we will know more, we will inform our audience.

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Category: Consequences, Hazard, Mitigations, Optimum Risk Estimates, Risk analysis, Risk management, Uncategorized

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