Ann: Update on Financing and Production, page-81

bdell thumbs up from me to you , however based on a little questionable arm chair knowledge I am aware of (plus a little in the field) , there are three other factors apart from the two you mentioned of recovery rate and throughput that determine production level which are :
3, ore grade ,
4, plant availability (which causes a discrepancy between weekly and yearly pruduction level ) for the same tph.
5, and the fickle variable of ore concentration in solution which partly is explained by slimes (a common problem in mineral sands operations ) but also occurs with CIL plants and is one reason why often it is advisable to mix oxide ore with sulphide ore to get the sulphide ore in suspension rather than being gunk on the bottom of the agitator tanks.
In this case it is more tricky as they are limited to (refractory) sulphide ore as it is unlikely that oxide ore of high grade is available and the effects of that ore could be negative in the Albion process where sulpher is needed.
My guess is they are looking at alternative sulphide ore sources that may mitigate the effects of "slimes" thus increase recoveries plus life of mine.
Be interesting what the bankers are thinking about PGI.