announcement - nabanga has more gold, page-19

"I agree that the grade is starting to look lower as they dril more - Central zone AVERAGE dropped 30%"

I have not looked closely, But is that not expected with any deposit as they step out from the centre with the drilling that the grade decreases, and is part of delineating the resource boarder.
If they can increase the tonnage with another 10km of strike say then they can expect to start to lower the cut off grade to through better economies of scale with the mill and machinery.

As for block modelling with wireframes like in Vulcan to work out the resource thats all beyond me even if I had the program I wouldnt have a clue how to input the info to get a krig.

I would think heap leaching is cheaper than gravity seperation (really mass seperation if using centrfuges)and centrifuges are probably needed unelss they can find a good water source to sluice, as with heap leaching they will only need to crush to around p80>20mm where as with HMS they will need to grind down to someting around (75 microns all big guesses here.) DOnt know if the ore is amenable to heap leaching though

I would think the high grade zones are "shoots coming up from depth" as likely to be a volcanic source and the laterite on surface is some type of transported material.

Really to get any further info and more accurate info as I am no geo or meatallurgist so a geo should post on here so I will leave you guys as I cant add any more to the discussion -cheers