New Broker Research, page-119

As i understand it....
600ktpa is the upgraded pilot plant on site.
800ktpa (if it goes ahead) is the new plant at a different location (e.g. Isa, or Townsville). This is on top of the pilot plant. In theory, they could keep both running at same time for 1.4mtpa. But Id assume you'd then want to increase resource size through drilling if producing above 800ktpa (which has 10 year mine life).