Ann: Owner Mining Commences at Granville, page-103

Anyone who has been involved in commissioning and maintaining a processing plant will know the continuous improvements and adjustments will need to be made, especially during start-up or ramp-up. The change of ore grade (increase or decrease) can have significant impacts on the plant efficiency, lost product & product quality and need to be worked through largely on a trail and error basis using empirical evidence.

It's a fairly simple process so can't see there being too many variable that need to be fine tuned for optimum performance. The bigger risk is the age of the equipment and breakdowns causing downtime. Good thing though is they have been running the plant at limited capacity which will hopefully have ironed out some teething issues by now.