Picnic at Mount Fort Constantine. On the way back to Cloncurry, the group detoured to Mount Fort Constantine, just over 10 km southwest of the Ernest Henry mine, where they had a very late lunch. Mount Fort Constantine is an up to 20 m high, 500 x 100 m outcropping ridge of brecciated, 'red-rock' and magnetite-altered, Mount Fort Constantine Volcanics, the closest exposure to, and the same rocks that host, the ore at Ernest Henry. When they had studied the outcrop and finished their lunch, the group moved 500 m to the southeast, to an overgrown quarry where the same breccias are strongly actinolite-magnetite altered and anomalous in uranium, and have been exploited for magnetite to be used in coal washing (inset). There are no (or minimal) sulphides at this locality.
    During that day, we had seen a structurally-controlled, cross-cutting "pipe" of Cu-Au-U-bearing magnetite-sulphide matrix breccia within volcanic host rocks (Ernest Henry); a stratabound magnetite-altered unit within a volcanic pile, with Cu-Au-bearing sulphides (E1 North - 8 km east of Ernest Henry); and brecciated volcanic rocks with magnetite and U mineralisation, but without sulphides, Cu or Au (Mount Fort Constantine -10 km southwest of Ernest Henry).
    From there, the group returned to the Gidgee Inn at Cloncurry, and after freshening-up, assembled in the function room where two members of the group delivered presentations on other examples of IOCG mineralisation to the tour participants, and geologists from Xstrata-Ernest Henry and Altona Mining (our hosts on Wednesday), who then joined us for dinner as our guests.   Photographs by Mike Porter.