The Chinese, due to their domestic policies over the last few decades have a huge surplus of young males, in the sense that the male:female balance is badly skewed. Something like 50M young men who can never get married. That's a powderkeg situation. China is shipping these young males to Africa hoping that they'll meet nice local girls, settle down, and effectively found Chinese colonies.

Now I'm not saying there's anything right or wrong about this. But if you want to understand why China is going about resource extraction so differently, you have to look deeper. In other words, minerals aren't the only resources...