Jantimot,From what I understand the bulk sample testing uses the...

Jantimot,

From what I understand the bulk sample testing uses the entire core. Hence it isn't cut, quartered and assayed like other drill core.

You seem to be missing the whole point of the bulk sample test work when you state... "the variability of grade is startling".
Of course the grade will vary, they are just highlighting the fact % grades going into the mill will range, 2% - 10%. Highest grade measured was 58% cu.
The point of a bulk sample being put through a pilot plant is to determine whether the circuit designed by the metallurgy team actually works.
They aren't designing the plant on lab drill results (albeit excellent grades), rather they are proving that all the ore types via a bulk sample can be processed through the primary, secondary and tertiary crushing, screening, gravity, milling, flotation, and magnetite separation steps on a large pilot plant scale.

I get the feeling some people are so fixated on 'absolute belief' in the jorc grade, they then can't understand how bulk sample results could be so much higher.
Once again do some research on how a geological jorc resource would asses an ore body like Rocklands and you'll be much more informed. In the meantime the bulk sample test work is giving you a major hint, whilst setting the expectation for actual mill grades.
DYOR