Mine Tailings Dams with John Metzger of Asset Assurance Monitoring

Today's episode is with John Metzger   / ismetzger   of Asset Assurance Monitoring, https://www.aamonitoring.net. "I don't know how, but I recognized it was one of my children. My friend rescued Nicolas, and I thought: Oh my God, at least I managed to catch one," said Emanuele's father, who had not been located by the time this edition went to press. This was reported in O Globo by DANDARA TINOCO AND MARIANA SANCHES on 08/11/2015 in the País section, page 7. It was translated by Google from Portuguese. 5 days later Emanuele was found dead. This was the Bento Rodrigues, or Mariana, dam disaster. It killed 19 people. The mine was owned by Vale and BHP. As reported by Associated Press, The mud from Mariana coursed some 670km along the Doce River to the Atlantic Ocean, destroying the surrounding ecosystem. At the time it was therefore referred to as Brazil’s worst environmental disaster. 4 years later, another dam collapsed. This was the Brumadinho Dam Disaster of 2019, killing 272 people including a family of 5, one of which was a pregnant mother. It was only 70km west of Mariana. It was also owned by Vale. Due to the number of lives lost, it is Brazil’s worst industrial disaster. When ore is extracted from a mine, waste is produced. This goes into a tailings dam. If the dam is not well designed, built, monitored and maintained, it can collapse. The fate of those in the way of the mud at Bento Rodrigues and Brumadinho awaits when that happens. Today’s guest, John Metzger, is an expert on monitoring systems for tailings dams. He has led an incredible life through many countries. We are privileged to have his attention. I was riveted by this story. I had to get some more numbers for you so I went to https://www.worldminetailingsfailures... which estimates there are 29,000-35,000 existing active, inactive and abandoned tailings storage facilities (TSF) globally. These contain approximately 223 billion tonnes of waste. Of these, 16,000 are currently active, with 85% of dam failures occurring in active facilities. You are wondering about Brazil given the chaos from 2015 to 2019 described in the introduction. Well, according to Agencia Brazil, as of November 2025 the country has 916 dams, 74 of which are at higher risk of collapse and 91 are on alert. The activist giving these numbers believes that disasters like this could still happen again, particularly in Minas Gerais (the state where there are 31 dams including the two collapsed ones mentioned in the introduction). "That's where Vale started what it calls the Southern Mining System."  A loose end to tie up about the Brumadinho Dam Disaster is that an alarm installed to warn of a collapse did not go off. This recalls the episodes recorded after the Camp Mystic flood where an alarm system also malfunctioned. Another wonderful prior guest, Juliette Murphy of Floodmapp, spoke of how we need a regulation for flood alarms just like we have one for fire alarms,    • Floodmapp  . It is a tragedy that humanity continues to fail to properly deploy such alarm systems as the precious few minutes they offer to escape could save many lives. So where does this episode leave us? It was about monitoring systems. It just so happens that the Brumadinho monitoring system had issues 2 days before the collapse: https://www.mining.com/web/brazils-va.... As such, critical data on an acceleration in movement of the tailings dam wall may have been missed with this malfunctioning. This acceleration could signal an imminent collapse. Another matter is pressure by the client, Vale, on the safety certification firm, Tuv Sud. As reported by mining.com, Namba, a Tuv Sud employee, said he felt “pressured” by Vale employees to certify the dam that later burst in Brumadinho was stable. As such, we are confronted by the age old feebleness of humanity. A couple of rays of hope. Last year the UN created a new organisation, Global Tailings Management Institute, https://thegtmi.org. This organisation is staffed by mining, engineering and community representatives to put a stop to the unnecessary, large loss of life at the hands of a poorly managed global set of tailings dams. I am also happy to say that I’ve found another expert to talk to on this matter - Ankur Shah of PlanetSapling. I reached out to him because Lindsay Newland Bowker, the actuary behind woldminetailingsfailures.org passed away only last month, May 2026. Her incredible global database of tailings dams must not be lost to time. I look forward to seeing what Ankur has as a continuation of her work. The opportunity here to do good is immense.