Greatland Resources Reports 62% Reserve Growth to 5.0Moz Gold as Telfer Drilling Campaign Delivers 150% Uplift

Telfer West Dome Open Pit Reserve Surges 375% to 1.4Moz Gold

The most striking individual component of the March 2026 Group Ore Reserve update is the West Dome Open Pit (WDO) at Telfer, which recorded a 375% increase in its Ore Reserve to 1.4 million ounces of gold. The WDO reserve now comprises 90.6 million tonnes grading 0.46 grams per tonne gold and 0.05% copper for 1.4Moz gold and 45,000 tonnes of copper, all classified as Probable. The announcement states that a higher-grade subset of 70.8 million tonnes grading 0.53g/t gold accounts for 1.2Moz of that total, highlighting the quality of the mineralisation within the broader pit shell.

The reserve is based on a Whittle optimisation shell modified through detailed pit designs, with only Indicated Mineral Resource material included. Inferred and unclassified material within the pit shell is treated as waste and assigned zero grade. The announcement notes that the WDO reserve was derived from approximately the first half of a planned 240,000-metre FY26 drill programme, meaning the update captures only a portion of the exploration work completed since Greatland assumed ownership. Metal price assumptions for the Telfer reserve used a medium-term gold price of A$4,000 per ounce and copper at A$6.00 per pound, compared to spot prices of approximately A$5,930 per ounce gold and A$8.70 per pound copper as at 27 June 2026, according to S&Amp;P Capital-iq/">Capital IQ data cited in the announcement.

Main Dome Underground Delivers a New 0.2Moz Reserve for the First Time

A notable milestone within the Telfer reserve update is the establishment of a Main Dome Underground (MDU) Ore Reserve for the first time. The MDU contributes 3.6 million tonnes grading 1.33g/t gold and 0.31% copper for 0.2 million ounces of gold and 11,000 tonnes of copper, all classified as Probable. The announcement states that this reserve has been defined across the active A Reefs, M Reefs, Eastern Stockwork Corridor, Kylo, Southwest, Western Flanks and Rey orebodies, all located in close proximity to existing infrastructure and requiring limited capital development to access.

The MDU reserve is based on conventional longhole open stoping, with cut-off grades ranging from A$51 per tonne for bulk stoping to A$158 per tonne processed for narrow reef stoping. Metallurgical recoveries average 90% for gold and 94% for copper from underground material. The company notes that current underground Mining rates are approximately 1.0 to 1.5 million tonnes per annum since cessation of the historical sub-level cave, with the vertical shaft and underground crusher providing what the announcement describes as substantial upside capacity for future underground mining. The West Dome Underground (WDU) and Vertical Stockwork Corridor (VSC) zones remain outside the reserve, both subject to ongoing drilling and studies.

Havieron Underground Reserve Unchanged at 3.3Moz, Anchoring Group Total

The Havieron Underground Project reserve remains unchanged from its December 2025 Feasibility Study declaration, contributing 38.5 million tonnes at 2.63g/t gold and 0.33% copper for 3.3 million ounces of gold and 128,000 tonnes of copper, all classified as Probable. Havieron continues to represent the highest-grade component of the Group Ore Reserve and remains a cornerstone of Greatland's long-term mine-life strategy alongside Telfer. The Havieron project is located approximately 45 kilometres east of the Telfer mine within the Paterson Province of the East Pilbara region in Western Australia.

The Havieron reserve uses long-term metal price assumptions of A$2,500 per ounce gold and A$4.60 per pound copper, unchanged from the December 2025 announcement. Cut-offs are applied using a variable break-even net smelter return calculation above A$82 per tonne processed, based on average metallurgical recoveries of 86.6% gold and 84.4% copper. With the Telfer reserve now substantially expanded, the combined Group profile offers what the announcement describes as a pathway toward a multi-decade mine life for the Telfer-Havieron complex, though no specific timeline is confirmed in the disclosure.

Telfer Stockpiles and Dump Leach Add Operational Flexibility to Reserve Base

Beyond the open pit and underground reserves, Greatland's March 2026 Ore Reserve incorporates 22.5 million tonnes of surface stockpiles grading 0.36g/t gold and 0.05% copper for 0.3 million ounces of gold and 11,000 tonnes of copper. Of this stockpile inventory, 1.9 million tonnes grading 0.69g/t gold and 0.13% copper is classified as Proved Ore Reserve, with the remainder classified as Probable. The announcement states that stockpiles provide operational flexibility and contingency for the processing operation.

A dump leach component of 2.0 million tonnes grading 0.19g/t gold with no copper recovery also forms part of the Telfer reserve, contributing a nominal 0.0Moz to the total at an average leach cost of A$4.9 per tonne and gold recovery rates of 30% to 50%. No copper is recovered from dump leach material. The Telfer processing facility comprises two parallel 10 million tonne per annum trains providing 20Mtpa nominal capacity, with all major infrastructure including power, water, transport and tailings already in place as part of active operations, as stated in the announcement.

Substantial Residual Mineral Resources Remain Outside the Current Reserve Boundary

One of the more significant disclosures in the announcement relates to the scale of Mineral Resources that have not yet been converted into Ore Reserves, representing a substantial pipeline of potential future reserve growth. The announcement states that West Dome Open Pit residual resources not included in the current Ore Reserve amount to 244 million tonnes at 0.45g/t gold and 0.04% copper for 3.5 million ounces of gold and 103,000 tonnes of copper. Of this, 24.5 million tonnes at 0.42g/t gold is classified as Indicated, while 219 million tonnes at 0.45g/t gold is classified as Inferred.

Underground residual resources outside the reserve total 53.9 million tonnes at 1.53g/t gold and 0.37% copper for 2.6 million ounces of gold and 201,000 tonnes of copper across the MDU, WDU and VSC areas. The announcement also highlights that Inferred Resources within the existing ORE pit shell, currently treated as waste, represent a potential opportunity to convert 42% more gold from the open pit, while Inferred material within underground mining shapes could add a further 8% in mined grade improvement if converted. The company notes that recent Inferred to Indicated conversion rates in the West Dome Open Pit have exceeded 85%, which the announcement describes as excellent.

Managing Director Shaun Day Sets Out Greatland's Multi-Decade Mine Life Ambition

Managing Director Shaun Day commented on the reserve update, stating: "Telfer and Havieron's combined Reserve of 5.0Moz gold and 196kt copper is an outstanding achievement and an important step towards a multi-decade mine life for the world class Telfer-Havieron gold-copper complex." Day added that the substantial uplift in reserves at Telfer reflects only twelve months of drilling since the company assumed ownership, with high-cadence drilling planned to continue driving resource and reserve upgrades.

Day also addressed the strategic importance of the open pit inferred resource conversion opportunity, noting that exceptional recent conversion rates have the potential to meaningfully lower the life-of-mine strip ratio within the ORE pit shell. He further stated that a key focus is advancing higher-grade underground opportunities at Telfer in parallel with the development of Havieron, with the aim of increasing the contribution of high-grade underground ore as a proportion of the processing feed over time. These are management statements as disclosed in the company's announcement; investors should conduct their own assessment of the timelines and risks involved in achieving these objectives.

Financial Close on $225 Million Revolving Credit Facility Strengthens Balance Sheet

Alongside the reserve update, Greatland confirmed that it has achieved financial close on Facility B of its US$500 million corporate debt facility. Facility B is a US$225 million undrawn revolving credit facility carrying a seven-year tenor, designated for Working Capital and general corporate purposes including Havieron development. The announcement references Greatland's 1 June 2026 disclosure regarding the execution of corporate debt facilities and Havieron approval as the originating event for this facility.

The financial close of Facility B provides Greatland with an additional undrawn Liquidity buffer as it advances both the ongoing Telfer drilling programme and the Havieron development project simultaneously. The company did not disclose the applicable Interest Rate, Margin, or any other specific financial terms of Facility B in this announcement. Investors may view the combination of an expanded reserve base and a secured but undrawn credit facility as evidence of progress on the company's twin-track operational and development strategy, though the ultimate financial outcomes will depend on prevailing metal prices and operational execution.

Telfer's 15Moz Historical Production Record Contextualises the Scale of the Current Mineral System

The announcement provides important geological and operational context for assessing the significance of the reserve upgrade. The Telfer gold-copper mine has produced more than 15 million ounces of gold since it first poured in 1977, establishing it as one of Australia's most significant long-life gold operations. The mine is located in the Paterson Province of the East Pilbara region in Western Australia, approximately 485 kilometres by road south-east of Port Hedland, and operates on a fly-in fly-out basis with a 1,700-room camp.

The existing processing infrastructure — including a gas-powered primary power station with 135 megawatts of capacity, a 20Mtpa processing plant, sealed airstrip, and established concentrate export routes — is described in the announcement as fully operational, with all major approvals in place. The announcement states that the Telfer ore reserves are considered to be at a pre-feasibility study level of accuracy or better, and that mining, metallurgical and economic modifying factors applied to each area are based on current operating practices. This infrastructure advantage is central to Greatland's stated strategy of utilising its large-scale, low-cost processing capacity for the long term.

West Dome Underground and Vertical Stockwork Corridor Represent Key Catalysts for Future Reserve Growth

Two areas that are conspicuously absent from the current Ore Reserve — the West Dome Underground (WDU) and the Vertical Stockwork Corridor (VSC, located below the historic sub-level cave) — represent what the company describes as significant potential future catalysts. Both areas are currently classified within Mineral Resources and are subject to ongoing studies. The underground residual resources across MDU, WDU and VSC total 53.9 million tonnes at 1.53g/t gold for 2.6 million ounces, with Indicated resources of 40.2 million tonnes at 1.43g/t gold contributing 1.8 million ounces of that figure.

The announcement states that the paste plant and distribution network used historically at the Rey deposit for cemented paste Fill is maintained and available for future opportunities such as the WDU resource. The company indicates that future reserve and resource growth will be targeted by maintaining current drilling rates into FY27 and continued study work at WDU and VSC. No completion dates for these studies, nor any timeline for potential WDU or VSC reserve declarations, are provided in the announcement. Investors may regard these areas as material upside to the published 5.0Moz Group Reserve figure, contingent on study outcomes and ongoing drilling results.

Share Price Context and Investor Considerations for GGP

The immediate share price impact of this announcement was not clear from available public information at the time of writing. Greatland Resources is dual-listed on the Australian Securities Exchange and London's AIM market under the ticker GGP, meaning that trading responses may differ between the two markets depending on session timing, liquidity, and investor base. The announcement was flagged as containing inside information under UK Market Abuse Regulations, with that information considered to be in the public domain upon release via a regulatory information service.

Investors evaluating the announcement should note several analytical considerations. The reserve update is based on metal price assumptions — A$4,000 per ounce gold for Telfer and A$2,500 per ounce for Havieron — that are materially below spot prices of approximately A$5,930 per ounce cited in the disclosure, which suggests a degree of conservatism in the reserve Economics. Equally, the scale of Inferred Resources within and adjacent to the current reserve boundaries — combined with conversion rates exceeding 85% at the West Dome Open Pit — implies that the 5.0Moz reserve figure could grow materially as drilling continues. The WDU and VSC studies, Facility B availability, and ongoing FY27 drilling results are the near-term milestones investors may wish to monitor closely.