Australia

Cadia PC1-2 Expansion Project

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Overview

Mine TypeUnderground
StageConstruction
Commodities
  • Gold
  • Copper
  • Silver
  • Molybdenum
Mining Method
  • Panel caving
Production Start... Lock
Mine Life16 years (as of Jan 1, 2022)
ShapshotPC1-2 is the next panel cave for execution at Cadia after PC2-3 and its development is expected to recover approximately 20% of Cadia’s published Ore Reserves.

Newcrest released the Cadia PC1-2 Feasibility Study on 11 November 2022. PC1-2 Feasibility Study approved to execution with development underway.

Main works development has commenced, with development forecast to be completed in January 2027. Production is forecast to commence in FY26.
Related AssetCadia Valley Operation

Owners

SourceSource
CompanyInterestOwnershipInvestor's Info
Newmont Corp. 100 % Indirect
Cadia Holdings Pty Ltd. (operator) 100 % Direct
Cadia is 100% owned by Newcrest through its wholly owned Subsidiary, Cadia Holdings Pty Ltd.

On November 6, 2023, Newmont Corporation completed the acquisition of Newcrest Mining Limited to create the world’s leading gold company with robust copper production.

Deposit type

  • Vein / narrow vein
  • Porphyry
  • Skarn

Summary:

The Cadia East deposit is hosted within the Forest Reef Volcanics and porphyry intrusions. A north-east trending mass of narrow sheet like dykes of monzonitic to dioritic compositions intrude the lower parts of the FRV at Cadia East. These intrusives are largely restricted to the eastern half of the deposit although some narrow dykes and isolated bodies of monzonite have been recognised in the western end. At the upper western end of the deposit immediately underneath the Gibb Fault, isolated narrow intersections have been identified with south dipping mineralised quartz veining. These occurrences are interpreted to be the Cadia Hill Monzonite.

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.

Geology
Mineralisation is developed in the 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 been intersected at depth, and consists of finely-bedded siltstone interbedded with basaltic volcanic rocks. Overlying this unit are five lithofacies of the FRV:

* Upper bedded unit: about 80 m thickness of finely planar-laminated feldspathic siltstone;
* Volcaniclastic unit: approximately 200 m thickness of sandy matrix polymictic conglomerate and volcaniclastic sandstones and locally volcanic breccia;
* Lower bedded unit: around 60 m thickness of bedded calcareous sandstone typically altered to skarn mineral assemblages;
* Massive volcanic rocks: about 150 m thickness of massive pyroxene phyric basalt to andesite lavas;
* Lower sequence: at least 1,100 m thickness of polymictic conglomerates and volcaniclastic sandstones.

Intrusive porphyry dykes and sills are interpreted to be co-eval with the FRV volcanic units. In the Cadia East area, the 5–30 m thick porphyry dykes appear to be stratigraphically controlled by the bedded units, and acted as feeders to overlying sills. The largest dyke has been traced for 1,500 m along strike, are coincident with a change in shape of the orebody on section 15570E, and are cross-cut by mineralised veins. Two large porphyry sills located above the lower bedded unit can be traced along the upper portion of Cadia East. Numerous smaller sills and dykes also exist in this area. The uppermost of the units termed the capping porphyry and is thickest (~70 m) in the middle of the deposit.

Alteration
Mineralisation at Cadia East is associated with an alteration system that occurs in roughly concentric zones about the core of the deposit. Within this alteration system both pervasive and selvage styles of alteration are recognised. The pervasive alteration overprints regional propylitic (chlorite–carbonate–epidote) alteration and is characterised by variably intense albite alteration.

The selvage style of alteration is largely made up of three alteration types:
* Hematite/K-feldspar alteration associated with quartz veins (generally mineralised); * Phyllic alteration associated with faults;
* Iron carbonate–albite alteration associated with faults.

Structure
Three major groups of faults were identified, including:
1) Sericite–chlorite–clay (SCC) shears: Most common type of fault at Cadia East, and range in scale from millimetres wide to tens of centimetres wide. Infill can vary from friable sericite–chlorite to puggy clay–gouge. Pyrite is common, hence the former term of “pyrite fault”, which has been discontinued. The most continuous sub-set, the P Faults (P1, P2 and P3) are east–northeast–west–southwest-striking (parallel to the orebody) and transect the panel cave areas. These faults are anastomosing, and locally discontinuous with splays, and consist of SCC shears that are soft, present deteriorating ground upon exposure, and have a well-developed shear fabric. East–northeast–west–southwest- and east–southeast–west–southweststriking fault subsets appear to be limited to a 50–100 m strike length and do not have the continuity of the P Faults. The east–southeast-striking shears may be shear fractures that link the tensional fractures within a fault jog, hence their limited (<100 m) continuity along strike;

2) Carbonate–laumontite (Ca–La) faults: Highly fractured and veined zones to tens of metres wide. Calcite-laumontite mineralisation is common throughout the Cadia East system, but there are concentrations of calcite–laumontite on the hanging wall (Ca–La North) and footwall (Ca–La Central) sides of the higher-grade orebody (copper and gold), and on the northwest corner of the lower-grade copper zone (Ca– La West). No Ca–La zones were identified in PC2–3. Ca–La Central has not been identified above 5100 RL, and Ca-La North above 5500 RL. The faults are latestage zones of very poor ground conditions as a consequence of the hydration/dehydration of laumontite;

3) Carbonate faults: Related to late low-angle thrusts that are likely splays off the regional Gibb Fault. Characterised by zones of iron-carbonate–albite alteration and chlorite shearing around a zone of calcite veins, or intervals of calcite-rich puggy (sticky) gouge with an iron carbonate selvedge. The main Carbonate Faults interpreted to have an impact on PC2–3 are Carbonate 2 and Carbonate 5. The Cat Fault and Splay overlie PC2–3 near-surface and are zones of well-developed gouge, up to a couple of metres thick. The Cat Fault has been estimated to have at least 80 m of reverse movement. These faults will only be encountered when the PC2–3 cave reaches near surface and will not affect mining recovery.

Mineralisation
Mineralisation at Cadia East is 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 a relatively small cap to the overall mineralised envelope and has a core of disseminated chalcopyrite (and rare bornite), capped by chalcopyrite– pyrite mineralisation (Fox et al., 2009).

The deeper zone is localised around a core of steeply-dipping, sheeted, quartz–calcite– bornite–chalcopyrite–molybdenite veins, with the highest gold grades associated with the bornite-bearing veins. Copper and molybdenite form a mineralised blanket above and to the east of the higher-grade gold envelope.

Au:Cu values are vertically zoned. The upper, disseminated zone of volcanic-hosted mineralisation typically has low Au:Cu values (<1), whereas the envelopes of sheeted quartz-calcite-sulphide veins have higher Au:Cu values (typically >2).

Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Production

CommodityProductUnitsAvg. AnnualLOM
Gold Metal in conc./ doré koz 2313,700
Copper Concentrate kt 42670

Operational metrics

Metrics
Annual ore mining rate 00
Annual ore mining capacity 00
Annual milling rate 00
Ore tonnes mined, LOM 000
* According to 2022 study.

Production Costs

CommodityAverage
All-in sustaining costs (sold) Gold 0000000
Assumed price Copper 00
Assumed price Gold 0000
* According to 2022 study / presentation.
Net of By-Product.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M AUD  ......  Subscribe
Sustaining CapEx $M AUD  ......  Subscribe
Total CapEx $M AUD  ......  Subscribe
After-tax NPV @ 4.5% $M AUD  ......  Subscribe
After-tax IRR, %  ......  Subscribe

Heavy Mobile Equipment

Fleet data has not been reported.

Personnel

Mine Management

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Aerial view:

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