Greatland Resources Limited

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NEWS RELEASE | 30 March 2026

December 2025 Group Mineral Resource Statement

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION AS STIPULATED UNDER THE UK MARKET ABUSE REGULATIONS.  ON PUBLICATION OF THIS ANNOUNCEMENT VIA A REGULATORY INFORMATION SERVICE, THIS INFORMATION IS CONSIDERED TO BE IN THE PUBLIC DOMAIN.

Telfer grows to 8.0Moz (+150%), supporting a long-life operation

Telfer adds 4.8Moz of gold Mineral Resources at a discovery cost of $5 per ounce

Telfer Measured and Indicated Resource growth of 163% to 3.8Moz

Telfer and Havieron Mineral Resources of 14.9Moz ounces gold and 645kt of copper

Greatland Resources Limited (Greatland or Company) (AIM:GGP, ASX:GGP) is pleased to provide its Group Mineral Resource Estimate (MRE), as at 31 December 2025 (December 2025 Group MRE).

The December 2025 Group MRE includes Greatland's 100% owned Telfer and Havieron (Havieron unchanged) gold-copper projects, and a Greatland MRE for the 100% owned O'Callaghans tungsten-copper-zinc-lead deposit (O'Callaghans), detailed in a separate concurrent announcement.

Significant new growth and infill drilling since the previous resource update as at 31 December 2024 (December 2024 Group MRE) has resulted in resource growth and a material upgrading of resource classification. Approximately 134,000m of additional drilling from 1 January 2025 to 31 December 2025 is incorporated into the December 2025 Group MRE update. More than 100,000m of further drilling is planned in the second half of Telfer's record FY26 drilling program, which will inform future MRE updates.

The December 2025 Group MRE includes a maiden resource for the high-grade West Dome Underground Project, with potential for further growth and classification upgrade from ongoing drilling.

Key highlights:

§ Telfer and Havieron MRE grows to 14.9Moz - 550Mt @ 0.84g/t Au & 0.12% Cu for 14.9Moz Au & 645kt Cu

§ Telfer MRE grows by 4.8Moz to 8.0Moz (+150%)

-  Organic MRE growth delivered for a discovery cost of $5/oz

-  419Mt @ 0.59g/t Au & 0.09% Cu for 8.0Moz Au & 370Kt Cu

-  Classification upgrade: Measured and Indicated (M&I) Resource grows 163% to 170Mt @ 0.69g/t Au & 0.13% Cu for 3.8Moz & 249Kt Cu

-  M&I Resources are of an adequate level of geological confidence to be evaluated in the upcoming Ore Reserve Estimate update (targeted for June 2026 quarter)

§ West Dome Open Pit (WDO) MRE grows by 2.8Moz to 4.9Moz (+135%)

-  338Mt @ 0.45g/t Au & 0.04% Cu for 4.9Moz Au & 149Kt

§ Higher grade component of 258Mt @ 0.53g/t Au & 0.05% Cu for 4.4Moz Au

§ Main Dome Underground (MDU) MRE grows by 1.5Moz to 2.2Moz (+225%)

-  Active mining areas - 12.3Mt @ 2.14g/t Au & 0.41% Cu for 0.8Moz Au & 50Kt Cu

-  Sub-level cave (SLC) area - 37.5Mt @ 1.09 g/t Au & 0.33% Cu for 1.3Moz Au & 125Kt Cu

§ West Dome Underground (WDU) MRE: maiden 0.6Moz Au

-  Maiden MRE of 8.0Mt @ 2.30g/t Au & 0.44% Cu for 0.6Moz Au & 35Kt Cu, consists of:

§ Lower Limey Unit (LLU): 3.5Mt @ 3.36g/t Au & 0.51% Cu

§ Western Stockwork Corridor (WSC): 4.5Mt @ 1.47g/t Au & 0.38% Cu

-  Low cost organic growth with discovery cost of ~$9/oz

§ Telfer Stockpiles: 0.3Moz

-  24Mt @ 0.37g/t Au & 0.05% Cu for 0.28Moz Au & 11Kt Cu

§ Outlook:

-  H1 FY26 infill drilling successfully delivered a major upgrade in the M&I category supporting an updated Telfer Ore Reserve Estimate targeted for the June 2026 Quarter.

-  Following significant resource growth, particularly in the M&I category, Greatland's focus now shifts to advancing higher-grade opportunities including WDU and the MDU sub-level cave area.

-  Record FY26 drilling program continues with >100,000 metres of further drilling planned for H2 FY26 and a substantial drilling program expected for FY27

§ Economic factors: Telfer MRE incorporates updated cost (based on CY25 actuals) and revenue assumptions with assumed metal prices of A$4,200/oz for gold and A$6.50/lb for copper, compared to spot prices of ~A$6,500/oz and ~A$8.00/lb respectively

Greatland Managing Director, Shaun Day, commented:

"Telfer and Havieron's combined resource of 550Mt @ 0.84g/t Au & 0.12% Cu for 14.9Moz Au & 645Kt Cu has the potential to underpin a multi-decade, world class mining hub. Our investment in significantly increased drilling has delivered substantial organic growth, with the overall Telfer resource growing by 150% to 8.0Moz, and the higher confidence Measured and Indicated component by 163% to 3.8Moz.

"The growth includes a high-grade maiden resource at the West Dome Underground project, which shows significant potential for a new mining front at Telfer and remains the focus of ongoing drilling.

"This strong resource update has been delivered by Greatland's dedicated technical team who have executed an accelerated and extensive Telfer drilling program since taking ownership in December 2024.

"The significant growth in Measured and Indicated Resources, particularly at the West Dome Open Pit, is very pleasing with this material being of adequate geological confidence to be evaluated as part of our upcoming Ore Reserve estimate, which remains targeted for the June 2026 quarter.

"The scale of Telfer's resource demonstrates clear potential to fully utilise our low cost 20 million tonne per annum processing infrastructure well into the future. The technical team's focus is now to advance our higher grade opportunities including the West Dome Underground and the potential to restart Main Dome Underground's sub-level cave, which could augment our development of Havieron."

Telfer resource background and future opportunities

The December 2025 Telfer MRE (Table 1) incorporates all drilling available as at 31 December 2025 and comprises four key Mineral Resource areas (Figure 1), being:

§ West Dome Open Pit (WDO) (active mining operation)

§ Main Dome Underground (MDU) (active mining operation)

§ West Dome Underground (WDU) (near-mine resource)

§ Vertical Stockwork Corridor (VSC) (near-mine resource)

As part of Greatland's record 240,000m FY26 drilling program, more than 100,000m of further drilling is expected to be completed in H2 FY26 (after the 31 December 2025 data cut-off date for the December 2025 Telfer MRE). Greatland anticipates that this remaining drill information for FY26, and continued high drilling cadence at Telfer in FY27, will position the Company well for further resource growth and classification upgrades in subsequent MRE updates.

WDO is the baseload feed of ore mined at Telfer and, with stockpiles, underpins the full utilisation of Telfer's 20 million tonne per annum (Mtpa) nominal processing capacity. WDO's now sizable Indicated Resource of 102Mt @ 0.46g/t Au & 0.05% Cu for 1.5Moz Au & 51 Kt Cu includes a higher grade component of 79Mt @ 0.52g/t Au & 0.05% Cu for 1.3Moz Au & 41 Kt Cu. Importantly, this large volume of Indicated material is of an adequate level of geological confidence to be evaluated as part of the upcoming Ore Reserve Estimate update. Greatland is also advancing other 100% owned potential open pit resource opportunities, such as Main Dome Open Pit and the Southeast Hub satellite area.

Telfers existing underground infrastructure is underpinned by ~6Mtpa of underground crushing and hoisting (shaft) capacity along with surface materials handling that delivers underground ore directly to Train 1 of the Telfer processing facility. Increased utilisation of this existing infrastructure, through expansion of current mining activities in the MDU along with the potential for future development of WDU and VSC, is a key opportunity for Greatland, noting that MDU currently operates at a rate of ~1.0 - 1.5Mtpa. Higher underground output presents a compelling opportunity at Telfer given current underground mining grades are approximately three times higher than current open pit grades.

Greatland expects to release an updated Ore Reserve Estimate for Telfer in the June 2026 quarter.

Table 1: Telfer December 2025 Mineral Resource Statement

Notes: Mineral Resources are reported as at 31 December 2025, 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 Telfer MRE are applied based on a NSR using metal prices of A$4,200/oz Au and A$6.50/lb and current site cost and revenue assumptions.

Figure 1: Telfer December 2025 Mineral Resource (schematic)

West Dome Open Pit (WDO)

WDO continues to be the primary source of ore mined at Telfer and, with stockpiles, underpins the full utilisation of Telfer's 20Mtpa of nominal processing capacity. As such, the WDO has been the focus of a targeted resource growth drilling program during 2025, with 467 holes for over 87,000 metres of new growth drilling informing the December 2025 Telfer MRE.

The WDO MRE is 338Mt @ 0.45g/t Au & 0.04% Cu for 4.9Moz Au & 149Kt Cu, including a significant increase (+184%) in the higher confidence Indicated category to 102Mt @ 0.46g/t Au & 0.05% Cu for 1.5Moz Au & 51Kt Cu. Indicated material is of an adequate level of geological confidence to be evaluated in the upcoming Ore Reserve update.

The December 2024 MRE for WDO only reported fully costed ex-pit material above a breakeven cut-off cost. During 2025 Greatland carried out processing trials of existing low-grade stockpiles as well as direct tipping of low-grade ex-pit material (incrementally costed) to the Telfer processing plant to confirm metallurgical recovery assumptions. The result of these trials supported the inclusion of this material into the December 2025 MRE for WDO (Table 2) and aligns with Greatland's current operational approach of prioritising direct-tipping of all profitable material to optimise processing throughput, reduce rehandle costs and preserve surface stockpiles.

Table 2: West Dome Open Pit December 2025 Mineral Resource Statement

Notes: Mineral Resources are reported as at 31 December 2025, 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 Telfer MRE are applied based on a NSR using metal prices of A$4,200/oz Au and A$6.50/lb and current site cost and revenue assumptions.

The substantial increase in the WDO MRE (Table 2, Figure 2) was achieved by a combination of resource growth (drilling) alongside an update to both cost and revenue factors. Pleasingly, the outcome of the infill drilling within the potential extension to the Stage 7 cutback returned excellent conversion rates (>85%) from Inferred to Indicated resource category, providing confidence in the geological model and estimation methods that underpin 3.4Moz of Inferred Resource. Greatland will focus on Resource conversion (from Inferred to Indicated) in WDO throughout the remainder of FY26.

Figure 2: West Dome Open Pit December 2025 Mineral Resource (plan)

Figure 3: West Dome Open Pit 2025 Mineral Resource (long section AB as depicted on Figure 2)

Main Dome Underground (MDU)

Active mining Areas

Substantial resource growth in the active mining areas of the MDU has been achieved in the December 2025 Telfer MRE.

A total MRE of 12.3Mt @ 2.14g/t Au & 0.41% Cu for 0.8Moz Au & 50Kt Cu (Table 3) has been defined across the active A Reefs, M Reefs, Eastern Stockwork Corridor (ESC), Lower Limey Unit (LLU) and Rey areas. This is a 27% increase in contained metal relative to the December 2024 MRE for Telfer and underpins continued mining in the MDU, which currently contributes ~1.0-1.5Mtpa of ore to Telfer production.

Vertical Stockwork Corridor (VSC)

A key addition to the December 2025 Telfer MRE is the VSC area of the MDU, with a MRE of 37.5Mt @ 1.09g/t Au & 0.33% Cu for 1.3Moz Au & 125Kt Cu (Table 3).

This VSC was previously classified as a resource prior to Greatland ownership and, after technical and economic evaluation in 2025, has been reintroduced into Greatland's December 2025 Telfer MRE update. The VSC domain was previously targeted as part of a large scale sub-level cave (SLC) with no material mining of the SLC having occurred since 2023, noting any potential future mining would likely operate at a lower extraction rate than the historical SLC. The VSC resource is located directly below the previous SLC.

The resource is located proximal to key underground infrastructure which is underpinned by ~6Mtpa of underground crushing and hoisting (shaft) capacity along with surface materials handling that delivers underground ore directly to the Telfer processing facility.

Table 3: Main Dome Underground December 2025 Mineral Resource

Notes: Mineral Resources are reported as at 31 December 2025, 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 Telfer MRE are applied based on a NSR using metal prices of A$4,200/oz Au and A$6.50/lb and current site cost and revenue assumptions.

Figure 4: Main Dome Underground December 2025 Mineral Resource (isometric view)

The VSC is a structurally controlled style of gold and copper mineralisation hosted in a steep west-dipping fold-axial-related breccia and stockwork zone in brittle sandstone host rocks. The VSC mineralised zone has been recognised over a 1,000m strike length and 600m vertically with widths of up to 60m. The MRE model consists of estimates for gold, copper, cyanide soluble copper, sulphur, arsenic, cobalt, and density using Indicator Kriging. The VSC MRE is reported above a notional net smelter return (NSR) value of A$70/t and below the 4350RL. The NSR profit algorithm has been updated for the December 2025 MRE and is based on SLC non-selective mining practices, resource metal pricing, updated SLC underground mining and processing costs assumptions and contains no mining dilution.

The VSC is considered a well-informed estimate, supported by over 354 diamond drill holes with drill density ranging from ~50m spacing in the Indicated material up to 100m within the inferred material.

West Dome Underground (WDU)

The WDU emerged from the recognition that key geological structures hosting mineralisation in the Main Dome Open Pit repeat in the West Dome Open Pit, specifically the E Reefs and the Middle Vale Reef. Accordingly, it was proposed that the geological features that are key to mineralisation in the Main Dome Underground (Figures 1 and 4), may repeat below the West Dome Open Pit. The Main Dome Underground has produced more than 3.1Moz gold and 210Kt copper to date.

This concept was drilled from surface between 2009 and 2020 with 16 holes completed over the 3km strike. Drilling was accelerated in 2024-2025 from newly established underground positions with a total of 18,963m drilled to December 2025. Greatland's drilling has confirmed that the key geological units hosting the Main Dome Underground mineralisation are present in the WDU.

Greatland considers the WDU area to be geologically analogous to the currently operating MDU, which hosts a range of mineralisation ranging from narrow high-grade reef (A Reefs), sulphide replacement (Rey) and bulk stockwork mineralisation (SLC). Drilling to date in the WDU has targeted high-grade sulphide replacement within the Lower Limey Unit (LLU), while broad stockwork mineralisation, termed the Western Stockwork Corridor (WSC), has also been defined.

The maiden WDU MRE consists of 8.0Mt @ 2.30g/t Au & 0.44% Cu for 0.6Moz Au & 35Kt Cu across both the high-grade sulphide replacement (LLU) and broad stockwork (WSC) domains (Table 4).

Table 4: West Dome Underground December 2025 Mineral Resource

Notes: Mineral Resources are reported as at 31 December 2025, 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 Telfer MRE are applied based on a NSR using metal prices of A$4,200/oz Au and A$6.50/lb and current site cost and revenue assumptions.

The release of the maiden MRE for the WDU caps an exciting 12 months of exploration with over 10,000m of new diamond drilling confirming the high-grade mineralisation within the LLU, along with the identification of the much larger-scale domain in the WSC, both over a >600m strike length. Importantly, WDU remains open in multiple directions and is a key target for high-grade resource growth with multiple underground diamond rigs to remain focused on the WDU resource in 2026. With >20,000m of drilling planned, key objectives include infill of existing mineralisation to the north, extensions of the system to the south, and evaluation of the WSC's vertical extent.

Greatland continues to view WDU as an area of high geological prospectivity, given the area is analogous to the Main Dome Underground while also being proximal to Telfer's considerable ~6Mtpa installed underground crushing, hoisting (shaft) and surface materials handling system that delivers underground ore directly to the Telfer processing facility. The WDU has the potential to be a future mining centre that, if validated by ongoing mining evaluation and studies, could materially lift Telfer's underground mining rates and overall grades reporting to the Telfer processing facility.

Figure 5: West Dome Underground December 2025 Mineral Resource (isometric view)

Notes: AuEq has been calculated based on the metal prices of $4200\oz and $6.50\lb Cu and metal recoveries similar to the Main Dome underground resulting a calculation of AuEq = Au + Cu% x 1.06.

Telfer Stockpiles

Substantial surface stockpiles continue to be maintained at Telfer, providing flexibility, resilience and optionality to continue fully utilising Telfer's 20Mtpa processing capacity. The December 2025 Telfer MRE includes 24Mt @ 0.37g/t Au & 0.05% Cu for 0.3Moz Au & 11Kt Cu in stockpile resources.

Table 5. Telfer Stockpiles December 2025 Mineral Resource

Notes: Mineral Resources are reported as at 31 December 2025, 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 Telfer MRE are applied based on a NSR using metal prices of A$4,200/oz Au and A$6.50/lb and current site cost and revenue assumptions.

Comparison to previous Telfer MRE

Figure 6 below shows a comparison of the Telfer December 2025 MRE to the Telfer December 2024 MRE.

Figure 6: Waterfall chart of contained gold ounces reconciliation between Telfer December 2024 MRE & December 2025 MRE

Contact

For further information, please contact:

Greatland Resources Limited

Shaun Day, Managing Director  |  Andrew Bowler, Head of Investor Relations

info@greatland.com.au

Nominated Advisor

SPARK Advisory Partners

Andrew Emmott / James Keeshan / Neil Baldwin  |  +44 203 368 3550

Corporate Brokers

Canaccord Genuity  |  James Asensio / George Grainger  |  +44 207 523 8000

RBC Capital Markets  |  James Agnew / Jamil Miah  |  Scott Redwood  |  +44 207 029 0528

Media Relations

Australia - Fivemark Partners  |  Michael Vaughan  |  +61 422 602 720

About Greatland

Greatland is a gold and copper mining company listed on the Australian Securities Exchange and London Stock Exchange's AIM Market (ASX:GGP and AIM:GGP) and operates its business from Western Australia.

The Greatland portfolio includes the 100% owned Telfer mine, the adjacent 100% owned brownfield world-class Havieron gold-copper development project, and a significant exploration portfolio within the surrounding region. The combination of Telfer and Havieron provides for a substantial and long life gold-copper operation in the Paterson Province in the East Pilbara region of Western Australia.

Additional Information on the Telfer Mineral Resource Update

Telfer Gold-Copper Mine

The Telfer gold-copper mine is 100% owned by Greatland and is located in the Paterson Province of the East Pilbara region in Western Australia, approximately 485 km by road south-east of Port Hedland (Figure 7). Telfer first produced gold in 1977 and has produced more than 15Moz of gold to date.

Telfer is a fly-in fly-out mine with both open pit and underground mining operations, an established workforce and significant infrastructure. Gold and copper are produced by a large processing facility comprising two 10Mtpa capacity trains, totalling 20Mtpa in nominal capacity, that produces gold doré and a copper-gold concentrate.

Ore from Telfer is currently being mined from the West Dome Open Pit and the Main Dome Underground mine. The Telfer Mineral Resources are located across mining leases M45/6, M45/7, M45/8 and M45/33.

Figure 7: Telfer mine location map

Drilling Overview

The December 2025 Telfer Mineral Resource Estimate (Table 1) incorporates all drilling available as at 31 December 2025 and comprises of Mineral Resources estimates from the West Dome Open Pit mine, West Dome Underground, Main Dome Underground mine, and already mined stockpiles.

Drill hole data for the current Telfer Mineral Resource Estimate areas is largely based on drilling completed from 1998 to 2025, with a total of 87,240 metres of additional reverse circulation (RC) and 46,566 metres of additional diamond drilling (DD) included since the previous December 2024 Telfer MRE. The new RC drilling has informed the West Dome open pit Mineral Resource Estimate while the additional diamond drilling has informed both the Main Dome and West Dome Underground Mineral Resource Estimates.

The West Dome Underground Mineral Resource Estimate has predominately been defined with NQ diamond drilling, with a total of 16 surface diamond holes and 33 underground diamond holes.

Drilling standards have changed over the history of the Telfer deposit, with historical drilling adopting protocols and standards consistent with industry practice at the time of the program. Early diamond drilling was predominantly NQ diameter but more recently has been a mixture of HQ & NQ diameter. Historic RC drilling used crossover subs with face sampling hammers used for later drilling programs.

Several different down hole survey methods were utilised at Telfer at different times of data collection. These included down hole electronic multi-shot camera, single shot camera, gyroscopic and Miniature Multi-shot Tool.

Multiple checks and validations are conducted on the drilling and sample data, with holes not meeting the set criteria excluded from the Mineral Resource estimation.

More recent drilling undertaken since Greatland's ownership has been conducted to a high standard, and the Competent Person is of the opinion that the data used to inform these Mineral Resource estimates is considered suitable and fit for purpose.

Mineralisation

Mineralisation within the Telfer deposit is controlled by structure and lithology. Several styles of mineralisation are present including narrow high-grade reefs, pod-like mineralised bodies, sheeted vein-sets, sulphide replacement and large areas of low grade stockwork mineralisation.

In the upper sequence the highest-grade gold and copper grades occurs within bedding sub-parallel reef systems (M Reefs), with reef systems being concordant to lithology, laterally extensive (>1km) both along strike and at depth. The thickness of these reefs varies from 0.1 to 1.2m while grade can also vary from 5g/t to 50g/t Au and 0.2% Cu and 1.5% Cu. This mineralisation has been targeted by both open pit and underground mining methods to date and form part of the West Dome Open Pit and Main Dome Underground Mineral Resource Estimates.

Within the lower sequence, bedding parallel reef systems still carry significant high-grade gold and copper mineralisation (A Reefs), while sulphide replacement within the Lower Limey Unit (LLU) also represent significant metal endowment with this unit averaging 0 8-10m thick and grading from 1-10g/t and 0.5-1.0% Cu. The LLU mineralisation form part of the Main Dome Underground and West Dome Underground Mineral Resource Estimates.

Stockwork mineralisation is present throughout the Telfer deposit (upper and lower sequence) and is characterised by narrow, often discontinuous veins that crosscut stratigraphy. Some stratigraphic units have more abundant stockworks than others (e.g. brittle sandstone units) and vein intensity within stockwork can be greater adjacent to reefs. Stockwork mineralisation can also include areas of breccia that are dominated by quartz, carbonate and sulphides characteristic of the VSC. Primary gold mineralisation is typically associated with pyrite/chalcopyrite sulphides and quartz/dolomite gangue. There is a correlation between vein frequency and gold grade.

Large domains of stockwork mineralisation have been defined in both the underground and open pits, within the axial zones within both the West Dome and Main Dome anticlines. Stockworks are laterally extensive, between 0.1km to 1.5km scale and the geometry of the stockwork zones is related to structure and stratigraphy. Stockwork mineralisation from part of all Mineral Resource estimates at Telfer (WDO, WDU, MDU).

Sampling Practices

Geologists define sample intervals to avoid crossing key geological boundaries and determine assay methods. Most Mineral Resource drilling used HQ3 core for surface, while NQ is more common in underground drilling programs. Samples, typically half-core, ranged from 20cm to 1m while RC drilling collected 1m samples, with 2-5kg sub-samples for fire assay. Recent West Dome surface RC drilling used 1m intervals for Resource drilling and 2m for Grade Control, with 3kg splits from a cone-splitter.

The geologist logging the core defines all sample intervals. Sample intervals do not extend across mineralised and important lithological contacts. The geologist also nominates the assay methodology. Resource development diamond drill core is sampled as half-core, while grade control are sampled as whole core. Samples are crushed, pulverised, and assayed for gold by Fire Assay and base metals by ICP. Cyanide-soluble copper was tested via bottle roll leach with AAS analysis. Samples are processed at either the Telfer site laboratory or certified external laboratories.

Assay quality control protocols have followed evolving industry standards from 1998-2025, with rigorous procedures including certified reference material submission, coarse blanks, umpire laboratory checks, duplicate comparisons, and unannounced lab inspections. Regular monitoring and reporting ensure assay reliability, with only a small percentage of samples requiring re-assay due to potential bias or imprecision. While occasional batch-specific issues arise, corrective actions are taken, and overall data confirms confidence in assay results.

Resource Estimation & Classification

West Dome Open Pit and the Main Dome Underground Mineral Resources have been estimated through a combination of ordinary kriging (OK) or multiple indicator kriging (MIK) techniques depending on the mineralisation style. The background stockwork mineralisation is estimated by MIK while reef and vein style mineralisation is estimated through OK. The estimation methodology for VSC uses an indicator kriging approach to define the proportion of higher and lower grade gold (Au) mineralisation, where the nominal grade threshold used to define higher grade mineralisation is 0.6ppm Au. Ordinary Kriging is then used to separately estimate the Au grade of the higher and lower grade components, and an average grade of the two Au estimates is then calculated by weighting these using their respective proportions. In the West Dome Underground, OK was identified as the most appropriate method of estimation for both gold and copper in the LLU and western stockwork corridor (WSC) domains. Further details on the estimation methodology are provided in Appendix 1.

The Mineral Resource estimates have been constrained using appropriate drill hole data spacing parameters and geological control. Resource classification is based on a combination of geological confidence, average weighted distance and slope of regression statistics for estimated gold grades, and economic constraints (NSR).

The NSR cutoff for the December 2025 Telfer MRE uses the following economic assumptions:

§ West Dome Open Pit: Metal prices of A$4,200/oz Au and A$6.50/lb Cu, costs are reviewed annually and include mining, treatment and refining costs, payables, royalties and uses metallurgical recoveries that are well understood and vary based on ore type, oxidisation state and geochemical characteristics, with average recoveries assumption of 77% for Au and 74% for Cu.

§ Main Dome, VSC and West Dome Underground: Metal prices of $4,200/oz Au and A$6.50/lb Cu, with the MRE reported representing multiple mineralised lodes that have different cost profiles based on the selected mining approach. For the December 2025 Telfer MRE update the NSR cutoffs applied to the underground ranged from $70-113/tonne. The inputs to these cutoffs are reviewed annually and include mining, treatment and refining costs, payables, royalties and uses metallurgical recoveries that are well understood and vary based on ore type with recoveries assumption ranging from 75-97% for Au and 68-98% for Cu.

Reasonable prospects for eventual economic extraction have been assessed through evaluating active mining and processing practices and costs that support the assumptions used in defining economic constraints for the Mineral Resources. There are no known environmental, social, governmental / regulatory or legal barriers to declaring this Mineral Resource.

Comparison to Telfer's Previous Mineral Resource Estimate (Telfer December 2024 MRE)

The previous Mineral Resource Estimate for Telfer was reported by Greatland as at 31 December 2024.

In the West Dome Open Pit, the Mineral Resource was previously spatially constrained by an optimisation shell based on A$3,450/oz gold and A$5.30/lb copper prices and all cost and revenue assumptions to identify potentially economic material were included in defining the NSR cutoff.

In the Main Dome Underground, the Mineral Resource estimate was also previously spatially constrained by the detailed economic evaluations (using MSO "mineable stope optimisers") to spatially define potentially economic material using A$3,150/oz and A$5.30/lb copper prices.

For the December 2025 MRE for Telfer, the following material changes were made:

§ Update metal price assumptions to A$4,200/oz gold and A$6.50/lb copper, in the context of current spot prices of approximately A$6,500/oz gold and A$8.00/lb copper.

§ Updated cost and revenue assumptions based on CY25 actual operating costs.

§ Addition of the West Dome Underground MRE.

§ Addition of the VSC "vertical stockwork corridor" MRE.

§ Depletion of active mining areas and stockpiles.

Figure 8 Telfer MRE waterfall chart showing tonnage reconciliation between the December 2024 MRE and December 2025 MRE for Telfer

Figure 9: Telfer MRE waterfall chart showing contained gold ounces reconciliation between the December 2024 MRE and December 2025 MRE for Telfer

Group Mineral Resources Statement

Greatland's combined total 2025 Mineral Resource has increased to 550Mt @ 0.84g/t Au and 0.12% Cu, for 14.9Moz gold and 645kt copper, consisting of the December 2025 Telfer MRE and the previously reported December 2023 Havieron MRE for the 100% owned Havieron development project.

There has been no material change to the Havieron MRE published by Greatland on 30 May 2025 - please refer to Greatland's prospectus published on 30 May 2025 for further details.

Table 6: 2025 Telfer & Havieron Mineral Resource Statement

Notes: Mineral Resources are reported as at 31 December 2025, 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 Telfer MRE are applied based on a NSR using metal prices of A$4,200/oz Au and A$6.50/lb and current site cost and revenue assumptions. Cutoffs for the Havieron MRE was based on a NSR using metal prices of A$2,360/oz Au and A$5.20/lb Cu.

Table 7: 2025 O'Callaghans Mineral Resource Statement

Notes: Mineral Resources are reported as at 31 December 2025, 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 O'Callaghans MRE are applied based on a NSR using metal prices of US$25.74 lb W (equivalent to ~US$450/MTU APT), US$4.54 lb Cu, US$1.27 lb Zn and US$0.93 lb Pb.

Refer to the 'December 2025 O'Callaghans Mineral Resource Statement' announcement released on 30 March 2026 for full detail regarding the O'Callaghans December 2025 Mineral Resource.

Forward Looking Statements

This document includes forward looking statements and forward looking information within the meaning of securities laws of applicable jurisdictions. Forward looking statements can generally be identified by the use of words such as "may", "will", "expect", "intend", "plan", "estimate", "anticipate", "believe", "continue", "objectives", "targets", "outlook" and "guidance", or other similar words and may include, without limitation, statements regarding estimated reserves and resources, certain plans, strategies, aspirations and objectives of management, anticipated production, study or construction dates, expected costs, cash flow or production outputs and anticipated productive lives of projects and mines.

These forward looking statements involve known and unknown risks, uncertainties and other factors that may cause actual results, performance and achievements or industry results to differ materially from any future results, performance or achievements, or industry results, expressed or implied by these forward-looking statements. Relevant factors may include, but are not limited to, changes in commodity prices, foreign exchange fluctuations and general economic conditions, increased costs and demand for production inputs, the speculative nature of exploration and project development, including the risks of obtaining necessary licences and permits and diminishing quantities or grades of reserves, political and social risks, changes to the regulatory framework within which Greatland operates or may in the future operate, environmental conditions including extreme weather conditions, recruitment and retention of personnel, industrial relations issues and litigation.

Forward looking statements are based on assumptions as to the financial, market, regulatory and other relevant environments that will exist and affect Greatland's business and operations in the future. Greatland does not give any assurance that the assumptions will prove to be correct. There may be other factors that could cause actual results or events not to be as anticipated, and many events are beyond the reasonable control of Greatland. Forward looking statements in this document speak only at the date of issue. Greatland does not undertake any obligation to update or revise any of the forward looking statements or to advise of any change in assumptions on which any such statement is based.

Competent Person Statement

The information in this announcement pertaining to estimation and reporting of the Mineral Resource estimates is based on, and fairly reflects, information and supporting documentation compiled under the supervision of Michael Thomson, Principal Geologist at Greatland. Mr Thomson is a full-time employee of the Greatland Group and has a financial interest in the Company. Mr Thomson is a member of the Australian Institute of Geology (AIG) and has over 20 years' relevant industry experience. Mr Thomson has sufficient experience that is relevant to the style of mineralisation and type of deposits under consideration and to the activity currently being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting Exploration Results, Mineral Resources and Ore Reserves'. Mr Thomson consents to the inclusion in this announcement of the matters based on that information and supporting documentation in the form and context in which it appears.

Appendix 1: JORC Tables

JORC Code, 2012 Edition - Table 1 Section 1: Sampling Techniques and Data

JORC Code, 2012 Edition - Table 1 Section 2: Reporting of Exploration Results

JORC Code, 2012 Edition - Table 1 Section 3: Estimation and Reporting of Mineral Resources