I am not sure that China is the main problem. China playes almost openly its carts. It is rather USA with basically no real African policy which is the problem here.

Partition of Sudan may (or may not in fact) put China in a corner as they have invest in oil infrastructures in North. But US policy to stabilize South Sudan is, at the best, foggy for the momment.
Sitting on a gold mountain is useless when there is no mines to exploit it.

By the way, several post have been sent with info on China policy.