They're separated by the South China Sea.
True, this is based off of region, government types, etc
Cobalt is an essential material that is mainly used in lithium ion batteries which are found in smartphones and some electric vehicles. Congo provide majority of the worlds supply of cobalt. Although having a surplus of valuable materials, Congo is one of the poorest nations. Because of the lack of money, those who mine cobalt in the Congo do not used power tools, gloves or mask, but instead they use their hands. With that, the miners would be exposed to high level of cobalt. Lung disease and heart failure have been linked to high levels of cobalt, and the mines that produces it are blamed for destroying landscapes, polluting water sources, contaminated crops and a loss of soil fertility.
Hopes this help. Sorry if there is any grammar mistake.
Well it depends on multiple things like the climate, amount of precipitation and so on like in a desert its gonna be hard to have run off because the water will just soak into the ground through its cracks because it doesn't get sufficient water supply. hope this helps.