Citation

Santamarina JC, Torres-Cruz LA, Bachus RC. Science 2019; 364(6440): 526-528.

Affiliation

Geosyntec Atlanta, GA 30319, USA.

Copyright

(Copyright © 2019, American Association for the Advancement of Science)

DOI

10.1126/science.aax1927

PMID

31073052

Abstract

On 25 January 2019, the structure damming a pond filled with iron ore mining wastes (tailings) burst at Brumadinho, Brazil (1), causing a massive mudslide that killed at least 232 people. This tailings dam failure was only the most recent in a long list of catastrophic tailings dam accidents (see the first figure) (2, 3). Similar accidents also occur at electric power stations, where ponds are used to store coal combustion residuals such as fly and bottom ash. There are about 1000 operating ash ponds in the United States (4), and coal consumption patterns suggest that there may be more than 9000 worldwide. The catastrophic accident at the Kingston fossil power plant in Tennessee in 2008 (5) highlights the destructive potential of ash pond failures. Detailed analysis of tailings dam and ash pond failures shows that little-understood processes such as time-delayed triggering mechanisms are more likely to manifest when best engineering practices are disregarded.

Failure of the containment structure around mine tailings and coal ash is often followed by a fast-moving mudflow, which can run downstream for several miles, with catastrophic consequences. This liquefaction of the impounded materials may suggest to regulators and the public that the problem lies with the impounded materials themselves. However, in the absence of internal collapse or induced shear (for example, as a result of a seismic event), liquefaction and outflow of ponded ash and tailings occur after the dam has failed. Thus, liquefaction does not cause the failure, but rather the disaster that follows ...

Language: en