Ann: Significant Porphyry Au-Cu Mineralisation Width increases, page-116

Think resolution or Oyu Tolgoi are other deep deposits that start atleast 500m underground. I would say 1gpt atleast with similar intercepts plus 0.6% copper is justified. It breaks even at 1.2%cueq, so far the gold grade to copper grade is good.

Its not just the depth but also the surface infrastructure, if you want to mine at substantial rates then multiple declines may be needed, geological stresses also need to be considered and seismic activity. Mining these deposits normally starts at $500m capital expenditure and that’s a surface operation.