The Cadia East deposit occupies a mineralized 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 orebody.

At Cadia East, sheeted quartz-calcite-bornite-chalcopyrite ± molybdenite veins, oriented sub-parallel to E-SE trending monzonite intrusions define a high grade resource at depth (Wilson, 2003). Pervasive biotite-orthoclase-albite-magnetite ± actinolite alteration envelopes surround these veins forming a zone of calc-potassic alteration. Propylitic (epidote-magnetite-hematite-chlorite) alteration extends laterally away from this calc-potassic core (Wilson, 2003). Distinctive hematite dusting of hydrothermal feldspars occurs throughout the propylitic alteration at Cadia East, a characteristic feature of many alkalic porphyry Au-Cu deposits (Holliday and Cooke, 2007).

The Cadia East mineralization consists of a package of steeply dipping, sheeted quartz veins forming a near vertical slab with dimensions approximately 2.5 km long, greater than 1.6 km deep and at least 200 m to 300 m wide. A high grade gold core is found at depth towards the eastern end of this vein package. Smaller pods of higher grade material are located above and lateral to the high-grade core.

Mineralization at Cadia East can be divided into two broad overlapping zones: an upper, copper rich disseminated zone and a deeper gold-rich zone associated with sheeted veins. The upper zone forms ........

Cadia East deposit is a large underground mining operation using the panel caving method (Cadia East Project). The deposit is mined in a number of lifts each comprising multiple panels.

Concentrator 1: • Primary crushing in a 60-inch x 113-inch gyratory crusher. This was the main primary crusher for the original Cadia concentrator and now primarily used for surface stockpile reclaim; • Coarse ore stockpile (COS) to a live capacity of 40,000 t and subsequent reclaim facilities; • Distribution bin and double-deck vibrating screens for feed size preparation; • Secondary crushing, treating screen oversize, using MP1000 cone crushers; • High pressure grinding rolls (HPGR) unit treating screen undersize prior to the SAG mill; • Primary open circuit milling in a single 40-ft SAG mill fitted with a 20 MW motor. The motor will be upgraded to 22 MW. Oversize pebbles from the SAG mill are returned to the distribution bin; • Secondary milling in three ball mills, with the two original mills fitted with 8.7 MW motors, and a more recently installed third ball mill with a 16 MW motor. The mills are in closed circuit with cyclone classification for a target grind size of P80 of 150–190 µm. Concentrator 2: • Reclaim and conveying system to transfer ore from Concentrator 1 COS to Concentrator 2 facilities; • Secondary and tertiary crushing using MP800 cone crushers and open circuit prescreening; • Dedicated coarse (crushed) ore stockpile (COS) and apron feeder reclaim facilities; • Primary open circuit milling in a single SAG mill fitted with a 7.5 MW motor; • Secondary milling using a 7.5 MW ball mill and parallel Vertimill VTM1250, in closed circuit with classifying cyclones. • Tertiary milling using a Vertimill VTM 3000. Cadia’s operating and financial performance in FY22 was impacted by reduced throughput rates during the planned replacement and upgrade of the SAG mill motor which commenced in early July 2021 and was successfully completed in November 2021, together with the expected decline in grade.

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