It's all about who (BHP/IGO/Twiggy/POSCO/Jinchuan) can get their hands on 10+ year mine life at Odysseus.
BHP has low grade feed from Mt Keith and relies on the high grade feed from Nova and WSA to make smelting profitable at Nickel West.
To all newbies - do some research into just how strategic WSA is to all these players.
Above is not financial advice and my opinion only.