4.1 Hundred Years of Tailings Dams Lesson Learned
37
Fig. 4.1 Graphic representation of dams failures (https://www.riskope.com/2017/02/22/hundredyears-lessons-learned-tailings-dams-failures/). Columns bear decade’s accidents (total at the top
of column; column width is proportional to the total), colours correspond to geographic location,
numbers in the cells correspond to number of accidents in related geographic area for that decade
closed TSFs around the world makes it necessary to prioritize the mitigation tasks,
if we want to achieve a higher quality, be it at corporate or at national levels.”
Figure 4.1 shows a summary of the full publicly available record of hundred years of dams failures (https://www.riskope.com/2017/02/22/hundred-yearslessons-learned-tailings-dams-failures/) (originally from Bowker and Chamber
2015). Given the nature of tailings dams, their construction time and expected service life and closure, the effects of today’s risk mitigation programs will only slowly
become visible because the world portfolio will contain mitigated and unmitigated
(legacy) dams. During that period the public will perceive at best a status quo and the
industry credibility and SLO will remain at stake (Oboni and Oboni 2014a, b; Oboni
et al. 2013). This is why the October 2017 UNEP-GRID Arendal (Roche et al. 2017)
report (See Sect. 4.1) recommends establishing an accessible public-interest, global
database of mine sites, TSFs and related research.
In summary, thanks to the historic studies performed to date it is possible to assume
the a priori range of the annual probability of failure of a dam goes from 10
−5 to 10
−3
based on 100 years performance history. The smaller value—i.e., 10
−5 —would be
for “top of class” structures.
For dams portfolios, if the design FoS are not known, prior analyses not available
the “indirect hybrid assessment method” can be used. This approach is also based on
historic approach to failure records (Oboni and Oboni 2013), empirical observations
(Oboni et al. 2014) and a systemic failure model (Oboni and Oboni 2016b) which uses
37
Fig. 4.1 Graphic representation of dams failures (https://www.riskope.com/2017/02/22/hundredyears-lessons-learned-tailings-dams-failures/). Columns bear decade’s accidents (total at the top
of column; column width is proportional to the total), colours correspond to geographic location,
numbers in the cells correspond to number of accidents in related geographic area for that decade
closed TSFs around the world makes it necessary to prioritize the mitigation tasks,
if we want to achieve a higher quality, be it at corporate or at national levels.”
Figure 4.1 shows a summary of the full publicly available record of hundred years of dams failures (https://www.riskope.com/2017/02/22/hundred-yearslessons-learned-tailings-dams-failures/) (originally from Bowker and Chamber
2015). Given the nature of tailings dams, their construction time and expected service life and closure, the effects of today’s risk mitigation programs will only slowly
become visible because the world portfolio will contain mitigated and unmitigated
(legacy) dams. During that period the public will perceive at best a status quo and the
industry credibility and SLO will remain at stake (Oboni and Oboni 2014a, b; Oboni
et al. 2013). This is why the October 2017 UNEP-GRID Arendal (Roche et al. 2017)
report (See Sect. 4.1) recommends establishing an accessible public-interest, global
database of mine sites, TSFs and related research.
In summary, thanks to the historic studies performed to date it is possible to assume
the a priori range of the annual probability of failure of a dam goes from 10
−5 to 10
−3
based on 100 years performance history. The smaller value—i.e., 10
−5 —would be
for “top of class” structures.
For dams portfolios, if the design FoS are not known, prior analyses not available
the “indirect hybrid assessment method” can be used. This approach is also based on
historic approach to failure records (Oboni and Oboni 2013), empirical observations
(Oboni et al. 2014) and a systemic failure model (Oboni and Oboni 2016b) which uses