They may need to go to GAM and buy that contractual right out which could be extremely expensive or create a new contract that promised GAM a bigger slice of the sales pie.
Negotiations every time they want to sell something could be cumbersome and is a third wheel in a relationship as GAM may want to go to the market and see what they could on sell for and get a better cut which might delay sales every time.
So then who are they mining for? Themselves and the shareholders? or GAM?
Might as well have shares in GAM if they own the rights to all the Tantalum and Lithium.
Pilbara hasn't been very clear as to how this arrangement will work.