They've been aiming for ten years worth of DSO (350Mt)for as far back as I can remember. They base all their calculations for capital repayment and capex for Itabrite production on this figure. The only problem is they have yet to prove up the 350Mt. I think from memory they've got JORC defined DSO of 215Mt currently and the rest is the reason for the current move to more drilling in Nabeba.
Might be worth you taking a look through the AGM presentation.
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