![\"Brumadinho](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2019\/02\/brumadinho_20190129_1014_logo_wm-e1549002564566.png\"){kind=logo}
Planet Labs<\/a> image showing the area covered by the tailings in the Brumadinho disaster. Image copyright of Planet Labs, used with permission.<\/p><\/div>\n .<\/p>\n The area affected is somewhat smaller than that of the Samarco disaster in Brazil<\/a>.\u00a0 The total ecological destruction in the river is clear.\u00a0 There is now an urgent need to retain the remaining tailings left in the storage area and to contain the waste, and any toxins draining from it, in the river channel.<\/p>\n Meanwhile, there remains considerable speculation as to the causes of the disaster.\u00a0 The image below is a Planet Labs<\/a> image collected on 25th January 2019, showing the dam that collapsed to generate the Brumadinho disaster:-<\/p>\n Planet Labs<\/a> image of the site of the Brumadinho disaster, collected on 25th January 2019, two days before the collapse. Image copyright of Planet Labs<\/a>, used with permission.<\/p><\/div>\n .<\/p>\n This image shows no obvious indications of ongoing work on the tailings dam itself, and there are no signs of work on the tailings stored in the pond.\u00a0 Indeed. there is also no obvious indication of the incipient failure developing.\u00a0 Thus, the events that led to the collapse remain intriguing, and it is going to be important to ascertain the causes if similar accidents are to be avoided.<\/p>\n The paper on the dam that I highlighted earlier this week<\/a> (Pirete and Gomes 2013<\/a>) shows that the dam was built using the upstream method.\u00a0 This is a cross-section of the structure:-<\/p>\n Indicative cross section of the tailings dam that collapsed to generate the Brumadinho disaster. Diagram from Pirete and Gomes (2013)<\/a>.<\/p><\/div>\n .<\/p>\n In this case most of the retaining structure is built upon the tailings themselves.\u00a0 This is not unusual, and it is not necessarily unsafe, but it does assume that the properties of the tailings are well-understood.\u00a0 Note in particular that the tailings are described as being dilative – there is a nice primer on the mechanical behavior of tailings here<\/a>, but in essence dilative tailings are assumed to show strain hardening, i.e. they will become stronger as they deform.\u00a0 This may be a key assumption on the context of this failure.\u00a0 It is perhaps worth looking at the report of the Samarco tailings dam accident<\/a>, which attributed the collapse to an extrusion process.\u00a0 In this case, failure also developed in a dam built using the upsteam method.\u00a0 The original design assumed that a layer of sand sitting over the tailings would be kept in an unsaturated state, but this was changed during construction, and the sands were allowed to become saturated.\u00a0 Ultimately, this allowed a so-called lateral extrusion event to develop, precipitating the collapse of the dam.<\/p>\n The operator of the site, Vale, are reported to have decided to remove all tailings dams of this type<\/a>.\u00a0 It will be interesting to see the timescale for these plans, and how they will monitor the stability of these structures in the interim so as to ensure no repeat of the Brumadinho disaster.<\/p>\n Pirete, W. and Gomes, R.C. 2013. Tailings liquefaction analysis using strength ratios and SPT\/CPT results<\/a>. Soils and Rocks<\/em>, 36<\/strong> (1), 37-54.<\/p>\n Planet Team (2019)<\/a>. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https:\/\/www.planet.com\/<\/a>.<\/p>\n Thanks to Robert Simmon of Planet Labs for his help in acquiring and processing the imagery.<\/p>\n","protected":false},"excerpt":{"rendered":" The human and environmental costs of the Brumadinho disaster in Brazil are becoming increasingly clear, whilst speculation continues as to the causes of the collapse of the tailings dam<\/p>\n","protected":false},"author":22,"featured_media":29949,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[102,20651,556,299,205,898,122,230],"class_list":["post-29947","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-brazil","tag-brumadinho","tag-features","tag-mine","tag-mining","tag-planet","tag-south-america","tag-tailings"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29947","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=29947"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29947\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/29949"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=29947"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=29947"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=29947"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Brumadinho](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2019\/02\/19_01-Brumadinho-7.jpg\")
![\"Brumadinho](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2019\/02\/19_01-Brumadinho-8-e1549003674211.jpg\")
References<\/h4>\n
Acknowledgement<\/h4>\n