Moy's AISC is projected to fall significantly during 2019, with the sulphide production, increased grades and likely increased recoveries, etc etc. See 9:30 onwards for a couple of minutes.
There's little doubt the sulphide processing will work, because Ausenco are doing the commissioning and they've already built 4 of these scavenging plants elsewhere.
Also, if you watch the very end, you'll see that Ausenco clearly see this as a marketing opportunity for them, so they must be very confident that the scavenging process has legs.