Goldhunter,
math is okay, even though its simple math:)
Just one aspekt. U should consider that sustaining capital incurs not all at once at the beginning of project. In fact it incurs distributed over minelife. Therefore capex would be recovered in about 3 years (still based on simple math).
If I find the time I'm gonna do a some more financial analysis based on more variables such as capex, opex, recovery.
Paschi