{"id":31090,"date":"2019-05-28T06:29:45","date_gmt":"2019-05-28T06:29:45","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=31090"},"modified":"2019-05-28T06:29:45","modified_gmt":"2019-05-28T06:29:45","slug":"gongo-soco-mine-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2019\/05\/28\/gongo-soco-mine-1\/","title":{"rendered":"Gongo Soco mine: another potential tailings dam failure in Brazil"},"content":{"rendered":"

Bar\u00e3o de Cocais: another failing tailings dam in Brazil<\/h4>\n

In Brazil another tailings dam<\/a>, at the Gongo Soco mine in Bar\u00e3o de Cocais to the east of Belo Horizonte, is at risk of failure.\u00a0 Multiple local news agencies<\/a> are covering the story, and contingency plans are in place.\u00a0 Fortunately, unlike at Brumadinho<\/a> and Samarco<\/a>, the potential failure of this dam has been detected prior to a major release of tailings (I noted that there was a risk at this site in March<\/a>), and a suitably cautious approach is being adopted.<\/p>\n

The best oversight of the issue at\u00a0Gongo Soco can be found in a detailed article on em.com.br<\/a> (in Portuguese – see the Google Translate version<\/a>), with a less detailed (but still useful) English analysis available via France 24<\/a>.\u00a0 The failure scenario in this case is quite complex.\u00a0 This is the Google Earth view of the site, on which I have marked the major features.\u00a0 The location is -19.973, -43.584:-<\/p>\n

\"Gongo

Annotated Google Earth image of the Bar\u00e3o de Cocais dam site at Gongo Soco mine in Brazil<\/p><\/div>\n

.<\/p>\n

At Gongo Soco, a large section of the pit wall in the abandoned Gongo Soco mine is displacing.\u00a0 Movement rates of 10 cm per year were routine in this section of wall, but in recent months this has rapidly accelerated, and in the last few days movement rates of 20 cm per day or more have been recorded.\u00a0 The volume of rock that is showing displacement is reported to be up to 10 million m\u00b3. The risk is that the collapse and runout of the slope will generate vibrations that trigger the failure of the Barragem Sul Superior (Sul Superior tailings dam) shown at the bottom of the image, allowing a major release of mine waste.<\/p>\n

To deal with the threat, Vale and the emergency services have evacuated 400 people, and a further 6,000 people are on notice to move should a release occur.\u00a0 High intensity monitoring of the slope is continuing.\u00a0 A Youtube video that describes the preparatory work being undertaken at the site<\/a>, which includes modelling of the inundation zone for a major failure:-<\/p>\n

\"Gongo

Modelling of the potential inundation one for a tailing dams failure at the Gongo Soco mine in Brail. Still from a Youtube video<\/a>.<\/p><\/div>\n

.<\/p>\n

On Monday night (27th May), the movement rate reportedly reached 21.8 cm per day.\u00a0 However, predicting the time of failure is notoriously difficult, so it is a waiting game.\u00a0 Ironically, a difficult scenario will arise if the slope does not fail during this movement period, which will leave a potentially dangerous slope intact.\u00a0 Knowing how to manage it in that case will be very challenging.<\/p>\n","protected":false},"excerpt":{"rendered":"

In Brazil another tailings dam, at the Gongo Soco mine in Bar\u00e3o de Cocais to the east of Belo Horizonte, is at risk of failure due to a rock wall collapse. <\/p>\n","protected":false},"author":22,"featured_media":31094,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6298],"tags":[102,71,281,122,230],"class_list":["post-31090","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tailings","tag-brazil","tag-dam","tag-rock-slope","tag-south-america","tag-tailings"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/31090","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=31090"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/31090\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/31094"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=31090"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=31090"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=31090"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}