npv

just fooling around I came up with this

taxed income 70% price per tonne
ounces 0 60,000 60,000 60,000 60,000 60,000 60,000 60,000 60,000 60,000
Price per ounce 650 650 650 650 650 650 650 650 650 650
OPEX tonne 350 350 350 350 350 350 350 350 350 350
Year 0 1 2 3 4 5 6 7 8 9
Revenue 0 39,000,000 39,000,000 39,000,000 39,000,000 39,000,000 39,000,000 39,000,000 39,000,000 39,000,000
Expenses 0 21,000,000 21,000,000 21,000,000 21,000,000 21,000,000 21,000,000 21,000,000 21,000,000 21,000,000
CAPEX 15,000,000
Gross income 0 18,000,000 18,000,000 18,000,000 18,000,000 18,000,000 18,000,000 18,000,000 18,000,000 18,000,000
Income stream -15,000,000 12,600,000 12,600,000 12,600,000 12,600,000 12,600,000 12,600,000 12,600,000 12,600,000 12,600,000
Present value -14,994,000 11,672,667 10,808,469 10,008,286 9,261,376 8,575,348 7,940,137 7,351,979 6,807,388 6,303,137
Net present value $63,734,787.68