Ann: Quarterly Cashflow Report-AVB.AX, page-63

I would think that the limiting factor with AN is the speed with which they can get the ore out of the ground and to the plant (other wise an expansion of AN would be a no brainer). I would think that they can not feasibly move more ore than they are already, whether that is because the can not widen roads, blast deeper, shovel quicker who knows. I really think they are moving it as fast as possible.

this would make a "trial mine" a great way to get more cash coming in. they have extra processing capability at AN, PB is going to be stage 2 but a full operation there requires more cash than they have/are willing to borrow, particularly when they are not entirely sure of how quickly they will be able to pull out ore in this new operation. A connecting road requires a tiny CAPEX, you max out AN capacity (to generate more cash and gain knowledge on the new operation) then build BP plant to the correct sizing (no wasted cash on over/undersized plant).