Copper mineralisation at Aktogay consists predominantly of chalcopyrite and occurs in quartz-carbonate filled stockwork fractures and as disseminations. It forms a compact body shaped like a flattened goblet within the rocks of the first intrusive phase and the volcanogenic sedimentary rocks of the Keregetas formation. The copper mineralisation is spatially associated with small stocks and dykes of porphyritic granodiorites and later granodiorite porphyries.

The deposition of copper and associated minerals was structurally controlled by faulting. About 70% of the copper-molybdenum mineralisation is hosted by intrusive rocks, mainly diorites and granodiorites, and about 30% by volcanogenic-sedimentary rocks of the Keregetas Formation.

The stockwork and disseminated copper mineralisation with average grade in excess of 0.2% Cu was delineated by trenching and drilling over an area of 2.1 km by 1.6 km and to a depth of 600 m to 860 m. The vertical extent of the mineralisation at a 0.15% threshold is at least 1,000 m. The copper mineralisation is accompanied by molybdenite and low but recoverable quantities of gold, silver, rhenium and selenium.

The thickness of the oxide capping is variable, the average being 18 m and maximum about 60 m. There is a general tendency for the oxide capping to thicken eastwards. The base of oxidation was defined visually during core logging. In some drillholes it was also defined by a phase analysis. The visually dete ........

Aktogay is a large scale, open pit mine with a remaining mine life of around 25 years (including the expansion project) at an average copper grade of 0.35% (oxide) and 0.33% (sulphide).

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