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Description
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Tailings are finely ground waste rock produced as a by-product of standard mining projects as well as some industrial and power plant operations. Tailings are conventionally impounded behind a dam that is raised perpetually insofar as operations continue, thus amassing large volumes of materials (sometimes including supernatant pond water) in the process. The failures of some tailings impoundments have triggered downstream mass movements that have caused human, economic and environmental impacts, thus inviting considerable public attention and scrutiny. Developing a detailed inventory of these “tailings flows” facilitates a better understanding of the magnitude-frequency statistics, preconditioning and trigger variables, breach-outflow processes and downstream runout behaviour. Upon screening over 350 historical waste impoundment failure incidents in pre-existing secondary datasets, we have developed a comprehensive global database of 63 tailings flows from 1928-2020 while following strict case selection criteria with the support of satellite imagery, digital elevation models (DEMs) and source literature. Using a novel runout zonation method, the satellite images and DEMs were analyzed on geographic information systems (GIS) platforms to independently estimate runout distances, inundation areas and travel path angles of tailings flows. Depending on data availability or quality, we also summarized the background information, impoundment conditions and geotechnical indices to provide site-specific context to case histories. The collated data is aimed to (i) broaden the scholarly understanding of tailings breach-runout behaviour, (ii) provide comprehensive documentation while assessing the limitations of data availability and/or quality in the public domain and (iii) establish a consistent framework for reporting various properties of tailings dam failures and tailings flows. Lastly, we note that the data should be treated with prudence. Tailings impoundments are highly variable depending on the locality, and site-specific conditions exert strong controls on post-breach behaviour. As such, it is recommended that our database be used purely as a basis for screening-level assessments, case analog comparisons and academic research. For site-specific prediction studies undertaken by practitioners, targeted field observations, laboratory investigations and numerical models are essential.
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Related Publication
| Rana, N.M., Ghahramani, N., Evans, S.G., McDougall, S., Small, A., and Take, W.A., 2021. Catastrophic Mass Flows Resulting from Tailings Impoundment Failures. Engineering Geology, 106262. https://doi.org/10.1016/j.enggeo.2021.106262.
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