Tailings dams are earthen embankments used for storage of waste by-product materials, mostly liquids and solids. A design review protocol refers to a procedure for evaluating the engineering design, construction, and operation of the facility to guarantee its safety. The failure rate of tailings dams has historically been much higher compared to water-retaining dams. This was associated with progressive construction techniques and unique behavior of the slurry (Williams, 2021). Following the catastrophic tailings dam accidents of Mount Polley and Brumadinho, the mining industry had to rethink its design review protocols.
Firstly, a paradigm shift in terms of governance was among the main lessons from recent disasters. As it was found out, technical defects were often the manifestation of systemic failures when the production took precedence over safety. Now, design review protocols require an integrated approach and a high-level responsibility. Such an approach will ensure that the risk assessment process is comprehensive and takes into account all aspects of safety, including social, environmental, and technical.
Secondly, the indispensable role of independent oversight is the critical lesson. Formerly, many facilities conducted only internal assessments. Now, according to the new protocols, high-consequence facilities have to create their Independent Tailings Review Boards (ITRBs). Such independent panels conduct unbiased critical analysis of siting, design, construction, and closure plans. Such oversight becomes the crucial part of the safety margin, which will help to identify the so-called “blind spots” in the design.
Moreover, the lessons from the recent failures of tailings dams show that they do not occur because of the failure of a particular component. On the contrary, the tailings dam failures happen due to a complex multi-factor coupled evolutionary process that involves structural, hydrological, and human factors (Zheng et al., 2022). Therefore, the current design review protocols take into consideration such vulnerabilities, for example, foundation weakness and pore-pressure changes. Moreover, the advanced risk modeling methodologies become a part of design review protocols, which take into account transitional character of the risk and the role of human factor (Zheng et al., 2022).
Finally, another lesson was the importance of integration of environmental sustainability and resilience to climate change into the design review protocols. For instance, some extreme weather events might dramatically change water balance and increase the probability of the tailings dam overtopping. The current design review protocols require conducting climate change uncertainty modeling and prioritization of the environmental-friendly options (Qarahasanlou et al., 2022). The progressive restoration and conservative long-term stability assessment become obligatory parts of the design review process.
In conclusion, the devastating effect of recent failures of tailings dams prompted the mining industry to change its approaches to design review procedures. Mandatory introduction of independent oversight, multi-factor risk analysis, and sustainable environmental criteria into design review protocols is the necessary transformation. Such lessons show the importance of having a reliable design review mechanism, which is not only a regulation requirement but also moral obligation.
References
Qarahasanlou, A. N., Khanzadeh, D., Shahabi, R. S., & Basiri, M. H. (2022). Introducing sustainable development and reviewing environmental sustainability in the mining industry. Rudarsko-geološko-naftni zbornik, 37(4), 91–108. https://doi.org/10.17794/rgn.2022.4.8
Williams, D. J. (2021). Lessons from tailings dam failures—Where to go from here? Minerals, 11(8), 853. https://doi.org/10.3390/min11080853
Zheng, B., Wang, J., Feng, T., Wang, W., Zhou, Y., Cao, G., & Wang, Y. (2022). Risk evolution study of tailings dam failures disaster based on DEMATEL-MISM. Frontiers in Earth Science, 10, 906486. https://doi.org/10.3389/feart.2022.906486
