Mineralisation in the porphyry deposits occurs as sheeted and stockwork quartz–sulphide veins, and locally as broadly stratabound disseminated mineralisation (Cadia East) and skarn (Big Cadia and Little Cadia).

The Cadia district porphyry deposits have recorded a sequence of alteration and mineralisation events that evolved from early-stage magnetite-stable sodic, potassic and calc-potassic alteration with locally significant gold–copper mineralisation, through a period of transitional stage potassic alteration that introduced most of the gold–copper mineralisation. Propylitic and calc- silicate alteration were developed in the deposit peripheries at this time and a late stage of feldspathic alteration developed irregularly around the deposit margins and locally destroyed mineralisation.

The Cadia East–Far East deposit occupies a mineralised zone 2.5 km in strike length, 600 m in width and over 1,900 m in vertical extent. It is located below and to the east of the Cadia Hill deposit.

Mineralisation is developed in the Forest Reef Volcanics (FRV), and in a series of subvertical to steeply northdipping monzodioritic to quartz monzonitic dykes, that are termed the Cadia Far East intrusive complex (CFEIC). The syn-mineral nature of at least some of the intrusions is indicated by the presence of mineralised xenoliths within monzonite porphyry dykes that also host porphyry- style veining and alteration.

The Weemalla Formation has be ........

The current operations are planned as a series of three lifts (Lifts 1, 2, and 3). The relative elevation of these lifts and all underground infrastructure is expressed in mine height datum which is 5,000 m above AHD (i.e. 5,900 m mine Relative Level (RL) is equivalent to 900 m AHD). Lifts 1 and 2 are approximately 1,200–1,400 m high with their bases located at approximately 4650 mRL and 4450 mRL. Lift 3 sits below Lift 2 with a block height of 275 m and a base at the 4,175 mRL. Lift 1 refers to the following panel caves: PC1–1, PC1–2, PC1–4, PC5001. Lift 2 refers to the following panel caves: PC2, PC2–3, PC2–4 and PC2–5. Lift 3 refers to the following panel cave: PC 3–1.

Cadia East is accessed via two declines, the main access decline, and the conveyor decline.

The mining method involves inducing caving of the rock mass by undercutting a block of ore. Mining proceeds by progressively advancing an “undercut” level beneath the block of ore. Above the undercut level, the overlying host rocks are pre-conditioned using blasting and/or hydraulic fracturing, resulting in controlled fracturing of the ore block.

Following pre-conditioning of the overlying host rocks, broken ore is removed through an extraction level developed below the undercut level. The extraction level is connected to the undercut level by drawbells, through which the ore gravitates to drawpoints on the extraction level. The ore is removed by a load–haul–dump (LHD) fleet to ........

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