Back in 2011, I with my young family took a local bus north from Mariana, which diverted through several villages including that one Bento Rodrigues just below the dam, soon to be washed away. Through gaps in the trees we could glimpse those huge orange lakes just behind earth dams - it was obvious even to a casual tourist that it was a disaster waiting to happen. But the bus was run by the mining company, like all services around there, I suppose that’s why people didn’t complain more.
By the way I was told Brazil didn’t even make much from iron mines, as most of raw ore was exported to China, which got the real value.