system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does Congo have a near monopoly in Cobalt extraction? Is all the Cobalt in the world really only in Congo? Or is it something else? Congo produces 80% of the global cobalt supply. Why only Congo? Is the entirety of cobalt located ONLY in Congo?
gpt
Cobalt is mostly a by-product of copper and nickel mining.  There are massive copper and nickel deposits in the Congo.  However, another major factor is the lack of much mining and environmental regulation in the Congo.  They can mine a lot of cobalt, cheap, because they pay the workers low wages, to work in dangerous conditions, with little regard to the effects to the local environment.  So, it's simply cheaper for companies to buy Cobalt from the Congo than from many other places.

Thus, it's much like two farms in your town growing apples.  If Farm A can sell its apples for much less than Farm B, then Farm A is going to sell far more apples, even if Farm B can produce just as many apples as Farm A.