Havieron
Overview
Havieron is a world-class, brownfield, high-grade underground gold-copper deposit located in the Paterson province in the East Pilbara region of Western Australia, approximately 45km east of the Telfer gold-copper mine and is intended to leverage Telfer’s existing processing plant and related infrastructure to process the ore mined from Havieron.
The world-class Havieron deposit was discovered by Greatland in 2018 and advanced under an unincorporated joint venture between Greatland and Newcrest (2019 – 2023), and then Newmont (2023 – 2024).
In December 2024, Greatland acquired Newmont’s 70% joint venture interest in Havieron to consolidate 100% ownership of the project, as well as 100% ownership of the nearby Telfer mine and infrastructure where Havieron ore is intended to be processed.
Mineral Resource and Ore Reserve
Havieron Mineral Resource Estimate (December 2023)
The Havieron Mineral Resource Estimate is reported in accordance with guidelines and principles outlined in the JORC Code, 2012 Edition.
The Havieron December 2023 Mineral Resource Estimate is contained within a compact 650 metre strike length and is currently defined over 1,400 vertical metres. Greatland considers that the exceptional quality of the Havieron ore body is demonstrated by the ounces per vertical metre profile.
The Mineral Resource averages:
- more than 9,150 gold equivalent ounces per vertical metre through the top 300m of the ore body; and
- more than 7,900 gold equivalent ounces through the top 1,000m.
Notes:
- Grades are reported to two decimal places to reflect appropriate precision in the estimate, and this may cause apparent discrepancies in totals. Cutoffs for the Havieron Deposit Mineral Resources were based on a NSR using metal prices of A$2,360/oz Au and A$5.20/lb Cu.
The Havieron Breccia pipe, including the high-grade SE Crescent Zone, remains open at depth. In addition, there remains potential to identify further zones of economic mineralisation within the footprint of the currently defined breccia pipe (650m x 350m x 1,400m), where drilling to date has mostly focused on the SE Crescent Zone.
Havieron Ore Reserve
The Havieron Ore Reserve Estimate is reported in accordance with guidelines and principles outlined in the JORC Code, 2012 Edition.
Notes:
- Ore Reserves are reported as at 1 December 2025 and is based on the Havieron Mineral Resources detailed above. Grades are reported to two decimal places to reflect appropriate precision in the estimate, and this may cause apparent discrepancies in totals. Cut-offs for the Havieron Ore Reserve are applied on a break-even cut-off NSR of A$82/t processed, and metal prices of A$2,500/oz gold and A$10,141/t copper, average metallurgical recovery of 86.6% gold and 84.4% copper. Ore Reserves are reported within mining shapes based on a sub-level open stoping mining method with cemented paste fill. Reported metal was derived primarily from the Crescent Zone, and only the Indicated Mineral Resource component thereof. All Havieron Ore Reserves are reported as Probable Ore Reserves, no Proved Ore Reserves are reported..
Geology
The Havieron deposit is hosted within two primary basement sedimentary units of the Puntapunta Formation a thin planar biotite rich metasiltstone to meta-arenite (BS), and a thickly bedded white to pale green calc silicate actinolite marble (CS), both of which have been subject to low-grade regional metamorphism.
The deposit is comprised of an ovoid shaped zone of variable brecciation, alteration and sulphide mineralisation (the Breccia Pipe) which trends northwest to southeast with approximate dimensions of 650 m in length by 350 m in width and 1,400 m in depth along a northwest orientation. The Breccia Pipe includes unmineralised to low-grade crackle breccia and a series of mineralised cemented breccias. The highest-grade breccia occurs on the margins of the Breccia Pipe and is termed the South East (SE) Crescent Zone. The Breccia Pipe also includes relatively small dioritic intrusions with brecciated contacts or wall rock clasts within the breccias. The Breccia Pipe is intruded by a 20–30 m wide, north-northeast trending, steeply dipping post mineralisation dolerite dyke.
A sedimentary cover sequence of Carboniferous to Permian Paterson Formation approximately 420m thick unconformably overlies the basement rocks at Havieron which is comprised of a layer cake stratigraphy of mudstones, tillites and siltstone units that gradually shallow to the northwest. The cover sequence is unconformably overlain by a thin Tertiary cover.
MINERALISATION
Mineralisation at Havieron occurred as two main events: an early hydrothermal event (open space infill and sulphidic replacement) and a late hydrothermal event (low temperature overprint).
The early hydrothermal event occurred in response to brecciation and the infiltration of fluid(s) into the country rock. As the hydrothermal fluids (which included gold and copper mineralisation) precipitated into the brecciated bedrock, they formed interstitial cements. Sulphidic replacement occurred in response to a chemical reaction between the hydrothermal fluid and the metasedimentary wall rocks along sedimentary bedding planes or preferred metasedimentary layers. This process produced layer-parallel and locally discordant bands dominated by sulphides (pyrrhotite, pyrite and chalcopyrite) accompanied by lesser amounts of biotite, actinolite, calcite and uncommon scheelite, allanite, tourmaline and monazite.
The late hydrothermal event involved the ingress of cooler, retrograde stage hydrothermal fluids during the waning stages of the mineralising event, with minor enrichment of these zones in zinc (Zn) and lead (Pb) indicative of lower temperatures. The late-stage event is characterised by pyrite as the dominant sulphide phase occurring as a replacement of earlier pyrrhotite and/or presence of interstitial marcasite, clay, carbonate (siderite, calcite), quartz, poorly crystallised chlorite, and uncommon sphalerite, galena, chalcopyrite, and rare native gold.
High-grade gold and copper mineralisation occurs within the South East Crescent Zone which is characterised by a series of massive to semi-massive sulphide replacement/open space infill units, that have a sub-vertical dip and trend parallel to the southeast margin of the outer contact of the Breccia Pipe creating a crescent-like geometry. The bulk of the South East Crescent Zone has been infilled to a nominal drill spacing of 50–75 m laterally, and 50–75 m vertically.
In 2023 drilling defined a new high grade mineralised domain, the Link Zone, which is a moderately dipping 30 m wide by 200 m long zone of mineralisation that extends northwards from the existing South East Cresent Zone from the 4,000 mRL down to the 3,750 mRL. This zone is interpreted to encompass the high-grade core of what was previously referred to as the Eastern Breccia Zone.
Figure: 3D view showing the spatial association of the SE Crescent, NW Pod and Eastern Breccia targets in relation to the existing mineralised extents at Havieron.
Havieron-Interactive Model
The Havieron Project 3D model is for illustrative purposes only and uses previously reported JORC Mineral Resource and Reserve estimates and drill results released by Greatland up to July 2023. Any future production at Havieron is subject to a positive Feasibility Study and Decision to Mine.