What is the difference between an ultimate pit and an optimal pit?
The ultimate pit gives the highest possible undiscounted cash flow without considering the practicalities of access or scheduling targets. The optimal pit gives the highest possible net present value taking into account all operational design constraints. The optimal pit always lies inside the ultimate pit, and only in the rarest of cases do these two surfaces coincide. The plain truth is that if you are mining to the limits of the ultimate pit, you are wasting a lot of time and money.
