Sulfur in mining tailings is huge problem ( https://en.wikipedia.org/wiki/Acid_mine_drainage ). This one reason there is so much research in Li-S batteries. Plenty of material innovations have come from people looking at mine tailings and wondering if something useful could me made of it.
For 22 years I designed the electronics controls that ran Longwall Coal Mining Machines. I've been in many mines.
The problem with extracting things from tailings is that they are often contaminated with low levels of Thorium. Extracting the other things like Lithium, Sulfur etc, starts to build up the quantity of Thorium. Which sounds good if you want to build a molten salt Thorium reactor; I understand that China and India have prototype to come on line around 2027. Based on designs and experimental units that the US did in the ~1950s.
The tailing problem is that the company is how handling Nuclear Grade Material which causes the Nuclear Regulatory Commission (NRC) to show up at the mine site. No mine wants to deal with this paper work, and health ramifications, headache so the tailings are not used.
If the profit ratio to headaches would improve things might change.
Perhaps the problem is that you are either refining away the thorium, or refining away as much non-thorium as you can. Either way you end up with mostly-thorium, and we know that radioactive stuff gets angry in large groups.
Thorium does not get angry, because it's only slightly radioactive and it's not fissile. To start up a thorium reactor, you need enough plutonium or uranium spitting out neutrons to convert plenty of thorium to U233, which is what fissions and makes energy.
If you want an actual bomb, you need that U233 without any thorium, because the thorium mostly just turns to U233 when it absorbs a thermal neutron (i.e. slowed down by a moderator like graphite). In a bomb you're relying on fast neutrons.
Read enough books/articles on thorium reactors and you'll come across a photo of the US thorium stockpile, which is a great big stack of pure thorium bricks.
It doesn't always come from mining. A huge problem with acid rock drainage (ARD) showed up when they built a freeway in Pennsylvania by merely exposing the rock.
The concept of making batteries out of drainage because both contain sulfur is like making socks out of cow manure because both contain carbon. There's so much of the latter that you could never use it all, but also the ingredient is dirt cheap in pure form.
I have a side project that could convert ARD into industrial strength sulfuric acid, which is unbelievably difficult to buy and transport, despite it being the most common industrial chemical in the world after water.
I'm not sure the belt of pyrite is best labelled as the cause here.
It might have something to do with the inferred activities of Rio Tinto, a transnational corporation that is one of the largest mining firms in the world.
The river was polluted millennia before the Rio Tinto company came into existence. There's been mining operations along the Rio Tinto since ca. 3000 BC.
> But before the mining operations? Probably not very polluted.
From the wikipedia page:
"The discovery of multiple oxide terraces mediated by microorganisms at up to 60 metres above the current water level, and as far away as 20 kilometres from the current river's path, may suggest that the unusual ecosystem is a natural phenomenon since before human mining activities started in this region.[9]"
Once we stop using fossil fuels, maybe sulfur in mine tailings will become a valuable resource. Today, sulfur comes from desulfurization of fossil fuels.
