Ann: Rights Issue Timetable Withdrawn, page-47

I can believe that one. They say in the announcement that the NCU must be clean.
And that is because as you you rightly point out it is not a smelter, so they can not float off impurities. It is purely a furnace and ingot mould.

I do not have a clue why they had to spend $1.2 mill on a trial furnace to prove you can melt copper and pour it into a mould.

Obviously the NCU contains some level of impurity.

To me the casting machines were another smoke and mirrors trick by management to give the illusion of coming riches.