 Do these images look familiar? Well, if you're a regular plain difficult watcher, then you might be thinking, is the title wrong for this video? As looks suspiciously like the Mariana Dam disaster. But sadly, this video isn't a remake of the 2015 Tailings Dam failure. Instead, today we're looking at another tailing dam failure in Brazil in 2019, just over a two hour drive away. It seems that history is doomed to repeat itself and tragically, in events like this, lives are lost and the environment gets polluted. Today we're looking at the Bruma Genu, tailings, dam collapse and flood. As such, I'm going to rate it 8 on my plain difficult disaster scale and also 8 on my legacy scale due to the disaster killing more than the Fandau disaster and that lessons never get learned. The old saying, lightning doesn't strike twice, obviously didn't take into consideration, the company Vale. Okay, in my last video I was calling the company Vale rather than Vale, which is my bad. The company was one of the partners that ran the Fandau site. Another failure of a tailings dam in Brazil in 2019 resulted in a death toll of 259 and 11 people missing. The actual trigger for the disaster is unknown, but the journey to the monumental failure is oh so familiar to Fandau, and that is improper water drainage. The Corrigo de Feijão iron mine is a site upstream from Bruma Genu, meaning Jerez, Brazil. Dam one, which would be the epicenter for the disaster at the mine was built in 1976 by the Faterco Mineral Company. In 2001, the site was taken over by Vale SA. Right, now let's take a look at the design of Dam one, a Bruma Genu. It was constructed using the byproducts of mining, including waste rock and tailings, which were produced during crushing of the unprocessed ore and the subsequent ore concentration process. For the ore concentration process, water was used to assist in the gravity separation of ore particles from the waste tailings. It was also used in transportation to the dam. The whole purpose of the dam structure was to dewater these waste materials for long-term storage. The dam was constructed in 15 stages between 1976 and 2013. This involved beginning with a starter structure after which it is raised in stages by constructing berms on top of previously deposited and dried tailings. Although space efficient, this construction method is risky as the foundations of each subsequent raising is built on potentially unstable material. For this method to be effective, proper drainage is essential in preventing liquefaction of the tailings. These were tackled in two ways. The first was to help remove surface water and generally consisted of a series of surface canals that were designed to root the surface water, run on precipitation and sluice water to the Corrigo de Fijol beyond the toe of the dam. The second was to remove moisture from within the tailings by the formation of an open beach, which would promote a desiccant state within the sluiced waste material. The original starter structure didn't have drainage, but subsequent construction lifts had tow drains. By 2013, the dam had reached a height of 86 meters and no new raisings were done on site. However, tailings continued to be placed until 2016 when the ore concentration moved to a dry instead of wet process, reducing the need for a tailings pond. But just because the tailings had stopped being added to the impoundment, didn't mean it could just be abandoned and forgotten about. There was still the issue of the water in the pond behind the dam and the keeping of precipitation away from undermining the structural integrity of the site. The level was significantly reduced by May 2016, leaving a shallow depth of standing water in the impoundment far from the dam. By 2018, a number of issues in the dewatering system were highlighted, which included pump failures, drainage channels being blocked, and pipe work being disconnected during maintenance, all of which were a recipe for disaster. In an effort to reduce water levels within the dam, deep horizontal drains were used in 2018. These necessitated drilling into the dam to install a metal casing, followed by a 50mm PVC horizontal drain. 14 of these drains were installed across the various stages of the dam until number 15, when on the 11th of June 2018, as drilling went through the starter dam at the tow in the central region, movement was recorded in the structure. The bore collapsed and mud flowed from the hull, causing seepage to be seen from the dam. The area was cemented and grouted, and a deep horizontal drain program was then abandoned. Towards the end of 2018, two subsurface exploration programs were undertaken that were intended to collect information on the material properties of the dam and natural ground. This again necessitated boring into the dam. Eight bore hulls were drilled between December 11th 2018 and January 2019, and nine were dug on the other project. One more on the central portion of the dam at the crest of the eighth raising to install new piezometers was being dug on the 21st of January 2019, and this leads us on to disaster. On the 24th of January, the drilling was dug to a depth of 65.5 meters below ground elevation. The next day, the 25th, the drilling team returned to work and continued to extend the hull to around 80 meters, which is around the point that the drill bit would go from tailings into natural ground. Just after lunchtime on the 25th at around 1228pm, dam one experienced a catastrophic failure beginning at the left abutment. What was rare for this kind of disaster was that the whole thing was caught on video in this perfectly shot footage. As you can see, failure was sudden, leaving little chance for anyone to escape the flow of mud. The released effluence rapidly travelled through the mines canteen and offices, as well as houses and anything in its path. The flow made its way into the Peralpeba River, turning its banks into that characteristic orangey muddy colour. The disaster released around 12 million cubic meters of tailings. The metals and the tailings would eventually work its way into the river's soil, affecting the region's whole ecosystem. The death toll of a total of 270 people was largely made up of valley employees, with a few railway workers listed amongst the missing who were never found. Infrastructure damage was in the form of a road, railway and an iron ore railway bridge destroyed three kilometres downstream from the collapsed dam. Unsurprisingly, the company took a financial hit, with a 250 million real fine the day after the event. But as always with these things, that was just the tip of the financial iceberg. Valet's assets around US$3 billion were frozen, which in part tanked the company's stock. Just recently, in 2021, an agreement was made between Valet and the government to repair all environmental damage and pay the families of the people killed $7 billion total in compensation. Employees of the German contractor TUV tasked with monitoring the dam and a number of staff at Valet were arrested on suspicion of murder, falsification of documents and environmental crimes. The local population was hit hard economically as like with Fandau, agriculture was severely affected, with crops ruined and cattle killed in the flood. Fears of another dam failure at number six, which was next to number one, led to evacuations of nearly 24,000 people on the 27th of January. But what caused the so fast and dramatic failure of dam number one? Surveys undertaken leading up to the failure did not show any hints of the fate of the structure, but survey markers located along the dam crest that were checked manually approximately once a month were not sensitive enough to pick up small movements. The panel investigation highlighted several possible factors that together caused the instability of the dam. The design was a steep upstream constructed slope. Water within the tailings impoundment was allowed to get close to the dam crest, which resulted in the depositing of weak tailings. A lack of significant internal drainage that resulted in a high water level of the dam, particularly in the tow region. Leading up to the end of 2018, higher rainfall was experienced at the site further increasing the water level, which was exasperated by the surface draining system being compromised. All of these might have been okay in a more stable design, but sadly the upstream style is inherently poor due to the foundations of the dam being on loose, saturated, heavy and brittle tailings that had high stresses within the downstream slope, which created a marginally stable dam. This is a plain difficult production, all videos on the channel are creative commons attribution share alike licensed. These difficult videos are produced by me, John, in a not so sunny south-eastern corner of London UK. Help the channel grow by liking, commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods, as well as hints on future videos. I've got Patreon and YouTube membership as well, so if you fancy supporting the channel financially, you can check it out there. All that's left to say is thank you for watching.