I am guesstimating 30-40k ounces based on current drilling / access (and I have been since the start) but for a low all-in sustaining costs and for a company the size of EXU the economics are rather compelling (from memory my guess was something like average g/tonne x land size cubed - noting it was a very thin channel (i'm probably very wrong)).
Though for RMS they'd need it to be on the higher side of 100k ounces to make Mace even close to economical. I've got confidence that Mace continues but access is the issue and was cited by EXU from the start as there is prime agricultural land it continues through.