A dam that held back mining waste collapsed Friday in Brazil, inundating a nearby community in reddish-brown sludge, killing at least seven people and leaving scores of others missing.
Parts of the city of Brumadinho were evacuated, and firefighters rescued people by helicopter and ground vehicles. Local television channel TV Record showed a helicopter hovering inches off the ground as it pulled people covered in mud out of the waste.
That is exactly why mine operators in this county must have property engineered plans for tailing retention dams before being issued a permit to mine and be subject to inspections to maintain their permits.
Geologically speaking, yes, but then every mountain on the planet will eventually submit to erosion and gravity and disappear as well. There are many dams around the world that have been in continuous use for centuries, some dating back to the second century. There is no particular reason to be concerned about living downstream of any properly engineered dam anywhere in the world, unless climate change significantly changes the hydrology of the drainage area behind it forcing operators to dump large quantities of water to prevent it from overtopping beyond design capacity. Every major dam failure in the last hundred years can be traced to specific engineering shortcuts (often due to managerial and/or budgetary constraints.)
Unfortunately most of those shortfalls are discovered after a dam fails.
Modern engineering and material science have certainly reduced the likelihood of new dam failures but with enough concentrated rainfall over a short period of time nearly all dams not securely built into hard bedrock risk failure.
And fortunately, modern engineering is up to the task. Hoover dam (and pretty much every other major dam in the world) will be there for hundreds if not thousands of years if the Environmentalist don’t demand its removal.
There is very little rebar in a concrete dam. They are compression structures and that is the job of the concrete. Concrete actually continues to gain strength with time.
