The nickel miner has taken 49% in a joint venture that gives it 25% in the Greenbushes lithium mine and 49% in the Kwinana processing plant in Western Australia.
Chinese state and private investors have spent more than $16 billion over the last decade buying copper mines and projects including nearly 50 in Africa.
Nauru wants to trigger the so-called "two-year rule", which allows for a mining plan to be approved after two years under whatever rules are in place at that time.