Ann: Major Copper Discovery Confirmed at Storm, page-152

That calc is just for the deep zone. I've done a similar calculation for the shallow zone of 4100N - it's in the "Let's Talk DSO" thread. Have a look on p. 2 of that thread and look at the most recent version - I've updated it a couple of times. I won't post it here as I'll just confuse those who are skim-reading. Yes, they would start with the shallow zone first - it will be a cheaper way to start generating income. 4100N shallow will be the entree, the 4100N deep zone will be the main course - though that analogy makes it sound as though the shallow zone isn't all that significant...