A Tidal Wave of Mud – by Shasta Darlington, James Glanz, Manuela Andreoni, Matthew Bloch, Sergio Peçanha, Anjali Singhvi and Troy Griggs (New York Times – February 9, 2019)

https://www.nytimes.com/

A mining dam collapsed and buried more than 150 people. Now Brazil is casting an anxious eye on dozens of dams like it.

BRUMADINHO, BRAZIL — Luiz de Castro was installing lamps at a mining complex in Brazil late last month when a loud blast split the air. He figured it was just a truck tire popping, but a friend knew better. “No, it’s not that!” the friend said. “Run!”

Dashing up a staircase, caked in mud and pelted by flying rocks, Mr. Castro clambered to safety. But as he watched, a wall of mud unleashed by the collapse of a mining dam swallowed his co-workers, he said. Tiago, George, Icaro — they and at least 154 others, all buried alive.

The deluge of toxic mud stretched for five miles, crushing homes, offices and people — a tragedy, but hardly a surprise, experts say. There are 88 mining dams in Brazil built like the one that failed — enormous reservoirs of mining waste held back by little more than walls of sand and silt. And all but four of the dams have been rated by the government as equally vulnerable, or worse.

Even more alarming, at least 28 sit directly uphill from cities or towns, with more than 100,000 people living in especially risky areas if the dams failed, an estimate by The New York Times found.

In the disaster last month, all the elements for catastrophe were there: A bare-bones reservoir of mining waste built on the cheap, sitting above a large town nestled underneath. Overlooked warnings of structural problems that could lead to a collapse. Monitoring equipment that had stopped working.

For the rest of this article: https://www.nytimes.com/interactive/2019/02/09/world/americas/brazil-dam-collapse.html