Today's episode is with John Metzger of Asset Assurance Monitoring.
With his teeth and tongue encased in mud, his body entirely covered in wounds, and his left ankle broken, 24-year-old Weslei Isabel heard his 2-year-old son, Nicolas, who had just been rescued, ask a question to which, two days later, he still had no answer: “Daddy, what about Manu?”. Pulled from the mud thanks to the help of a family friend, the little boy was puzzled by the absence of his 5-year-old sister, Emanuele Vitória. Affectionately known as Manu.
I rested his head on my chest and said, “It’s in God’s hands.”
Lying in a hospital bed in Santa Bárbara, a city neighboring Mariana, Emanuele’s father yesterday described the despair that began when he saw enormous waves of mud, pieces of concrete, cars, fences, rocks, and trees hitting him after the collapse of the tailings and water dams. The maintenance worker was at home with his two children when the three were engulfed by the avalanche.
Weslei managed to grab them, but saw his children slip from his arms after being knocked down by a wall. Amidst the torrent, he held his breath once, twice, three times as he watched the waves of mud approaching. He knew that staying calm was his only hope for survival. Only after managing to free himself, after being thrown into a ravine, did he find a friend. With difficulty, he walked for half an hour along the edge of the affected area. Then, he heard a child crying.
“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 found in a wire from 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.org 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:
Brazil has 916 dams, 74 of which are at higher risk of collapse and 91 are on alert. The activist believes that disasters like this could still happen again, particularly in Minas Gerais (where there are 31 dams). "That's where Vale started what it calls the Southern Mining System."
Minas Gerais is the state where the two dams collapsed that are mentioned in the introduction.
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:
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. 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. 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.
