> The write-up is in response to a question asking how long dams like the Hoover Dam, which is a large concrete dam, are designed to last. It wasn't suggesting

> The write-up is in response to a question asking how long dams like the Hoover Dam, which is a large concrete dam, are designed to last. It wasn't suggesting that all dams are concrete. But the author mixes concrete dams with tailings dams, of which none (according to USACE) are concrete. That's what I meant by vague: starts with a large large number talking about US dams with, talks about concrete, mentions danger of tailings and then talks about foreign dams. The data is chosen for a narrative and ends up implying a lot without clear references.