Timbo,
I think you should be very cautious about applying the results of RAB/blast-hole sampling to anything meaningful. I don't know how they were sampled, but blast-hole sampling is notoriously erroneous. The drilling process might equally beneficiate the copper concentration (by winnowing out the lighter gangue) as under-report the NCu as you've highlighted. It should only be used as a Grade Control guide and as a step in the reconciliation of the Reserve estimate with production, and of course, for classification. I'm surprised that they didn't use angled RC Grade Control drilling in spite of their previous doubts about RC drilling. It still would have delivered a more reliable result in my opinion.
CDU Price at posting:
$1.11 Sentiment: None Disclosure: Not Held