And within that $13m was $6.8m related to Maggie Hay's mine work...

And within that $13m was $6.8m related to Maggie Hay's mine work that wouldn't be required in the context of using only the flotation plant.

With all the discussion about these mega 100Mt projects its sometimes forgotten that the maths on even 1Mt at say 1.3% is pretty good:
1,000kt * (1.3/5.5) * 70% = 165kt of SC5.5.

At say US$1,100/t for SC6.0 this is about A$1,474/t (assuming a 5% price discount for the lower grade and 0.65 exchange rates).
1Mt of ore has the potential to generate A$243m of revenue. If you have A$5 mining costs and a strip ratio under 9:1 then mining costs to get 1Mt will only cost A$50m. Some of that 15-20Mt is in that 30-50m zone that is near the surface and easy to get with a fairly low strip ratio. The challenge is finding a capital light option that enables the revenue to start flowing.