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Development of geotechnical practices

for tailings facilities over the years

by Bryan Ulrich

When I first became involved in tailings             using a deterministic approach.                   Author Bryan
       management, it was all about achieving
a stable design that would allow the flexibility     Some designs utilize the failure modes and Ulrich working in
needed for possible changes in the operation.        effects analysis (FMEA) method to assess their the field.
Sometimes those changes could be very difficult      associated risks. FMEA is a technique that takes
to accommodate, for example if the tailings
production rate doubled from the original design     into account the different manners of failure of
criteria.
                                                     a given element and identifies their effects on
    This was the 1980s. It isn’t that we were
oblivious to the environment, but it wasn’t a        other components and on the overall system.
top priority then. We used liners/lining, drains,
reduced head on the liners and incorporated          It is an iterative, descriptive and qualitative
seepage reduction measures. In retrospect, at
least in the Americas, we were doing just about      analytical approach that promotes, based on
what we do today with respect to environmental
protection measures.                                 available knowledge and information, systematic

    Over time, different tools became available      and logical thinking as a means to significantly
to tailings management professionals. Things
like probabilistic analyses, whether it is in the    improve the understanding        Bryan Ulrich, PE, Pr. Eng., D.GE,
water balance or slope stability calculations,       of the sources of risk and       member SME, is president/
probabilistic analyses were and are used to better   the justification of decisions   founder at Bryan Ulrich LLC,
capture the broader range of potential outcomes      related to the integrity of      email bryanulrichpe@outlook.
that may occur.                                      complex systems. Without         com.
                                                     the need for mathematical
    The hard science of geotechnical engineering
has not changed much in these intervening years.
Laboratory testing has remained essentially the
same (with a few noted exceptions), as has in situ
testing. Computer-based engineering analyses
have advanced in data entry and presentation of
results and sophisticated deformation analyses
have advanced considerably. But the underlying
principles of tailings facility geotechniques have
changed very little. What has changed are the
additional tools we now more commonly employ
to bolster the robustness of our designs.

    The additional tools would include the use
of risk analyses. I recall my first formal risk
assessment occurred in about 1996. Although it
wasn’t used for every project, and some clients
chose to forego this option, this approach has
increased in usage over time. Now, it is all but
required by the Global Industry Standard on
Tailings Management (the Standard, ICMM et
al, 2020). This is a very positive step forward for
everyone.

    Let’s discuss risk further. Risk is defined
as the product of the probability of an event
occurring and consequences resulting from the
event. Risk analyzes are a systematic process
of identifying and assessing these possible
results and associated probabilities. Because
risk analysis for tailings facilities includes many
uncertainties, the analyzes are often completed

www.miningengineeringmagazine.com	                                                    Mınıng engıneerıng    January 2021 1
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