Kalkaroo consists of stratabound replacement and vein style copper-gold mineralisation within Willyama Supergroup rocks of the Curnamona Craton.

The stratabound mineralization is uniformly distributed along more than 3 km of strike that follows an arc around the 35 degree dipping northern nose of the Kalkaroo south dome. It is hosted by an 80m -120m thick mineralised horizon that is sandwiched between psammitic footwall rocks and a thick pelitic hangingwall sequence.

In part, the mineralization is associated with near-vertical, mineralised quartz vein breccia fracture/fault fillings, which probably formed channel ways for the mineralising fluids. Interference folding resulted in dome structures which probably acted as structural traps for the rising mineralising fluids carried by these vertical structures.

The mineralising events were associated with iron-rich and sodium-rich alteration fronts, which are manifest as widespread fine-grained magnetite in the lower sandy formations and as pervasive albite alteration.

Erosion in the Mesozoic and Tertiary period exposed the Kalkaroo deposit to prolonged and deep weathering. Consequently, the deposit shows typical supergene enrichment features in its upper part, caused by oxidation of the primary sulphides in the weathering zone, forming a soft clay rich rock called saprolite. This is manifest in a subhorizontal stratification of the ore minerals from top to bottom:

1. Superge ........

The mining method is conventional open cut bulk mining using truck and excavator equipment. The PFS is based on an owner operated mining fleet.

The pit development is in a staged cutback to sequence extraction from generally high value to lower value and shallower to deeper ore over the life of the mine. The first year mining consists entirely of overburden pre-strip of the 50 or so metres of Tertiary sands and clays. The next three years are focused on mining the softer oxidized saprolite gold, native copper and chalcocite ore types at an annual production rate averaging around 4 million tonnes per annum, which is the nominal capacity of the oxide ore processing plant.

The ore mining rate almost triples in the fifth year peaking at approximately 12 million tonnes per annum and coinciding with the sulphide ore concentrator plant coming on stream in order to process the significant amounts of chalcocite ore being mined. The excess saprolite gold and native copper ore mined in this year will be stockpiled, with processing spread out over the next two years. With the bulk of the oxidized ore mined by the end of the fifth year, production in subsequent years is largely from deeper sulphide ores with a milling throughput rate of nominally 7 million tonnes per annum. As the mining operation moves deeper the proportion of chalcopyrite ore increases until it becomes the predominant ore type mined and processed in the later years.

Over the life of the ........

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