Poisonous Water

We have just left the Dutch couple to drive to a slightly bigger city, we need a new selfie stick, SSD card and a pair of sandals for Henrik.
The purchase doesn't quite go according to plan, but what do we do, we have plenty of time.
We continue towards a small town called Minas de Riotinto, where we will spend the night before the trip continues towards the coast.
We are holding a place that most of all looks like an open mine, but we will read it when we get there.
It turns out that there has been mining in this town for 4000 years, and everything to do with the town has something to do with the mine.
We read that there is a mine train that runs along the Rio Tinto, which is named after the color of the water in the river.
We are told that there is no wildlife at the river because if they drink from the water they would die from it.