I think this is very interesting. Quintessence (look at the...

I think this is very interesting. Quintessence (look at the link): Even with its immense size, Olympic Dam is very complex, with alteration and mineralization largely structurally controlled and highly variable. In fact, published data show that of nine holes drilled within 1 kilometre of the core of the deposit in 1975 and 1976, four were barren and were shown by later drilling to lie less than 400 metres from ore (Figure 1). The center of the Olympic Dam deposit is actually barren, and directly underlies the core of a corresponding gravity anomaly.

If you look at the whole Mumbwa project from this angle you may understand why it is so difficult to find the core of an IOCG deposit. Furthermore I ask myself why yesterdays drilling results have not more impact on the SP. "Based on the extent of the typical IOCG alteration observed in this hole, future drilling will test the potential for the core of an IOCG system to be located nearby" (from yesterdays announcements).

more info can be found (look at the figures of Olympic Dam and the drillings in 1975/1976) under this link.

http://www.crosshairexploration.com/s/IOCGModel.asp