Greatland Gold PLC (AIM:GGP) 2024 Group Mineral Resource Statement

Inaugural Greatland Telfer Mineral Resource delivers 3.2 million ounces gold and 117,000 tonnes copper, confirming Telfer mine life extension potential

Total Group Mineral Resources of 10.2 million ounces gold and 387,000 tonnes copper

Greatland Gold plc (AIM:GGP) is pleased to provide this 2024 Group Mineral Resource Estimate, which includes Greatland’s inaugural mineral resource estimate (MRE) for the Telfer gold-copper mine (Telfer).

Highlights

§ Inaugural Greatland Telfer MRE as at 31 December 2024:

‒    154Mt @ 0.64g/t Au and 0.08% Cu for 3.2Moz Au and 117kt Cu, comprising:

§ West Dome Open Pit: 115.6Mt @ 0.55g/t Au and 0.05% Cu for 2.1Moz Au and 61kt Cu

§ Main Dome Underground: 7.9Mt @ 2.62g/t Au and 0.51% Cu for 0.7Moz Au and 40kt Cu

§ Stockpiles: 30.6Mt @ 0.45g/t Au and 0.05% Cu for 0.4Moz Au and 16kt Cu

‒    46% of contained gold comprises Measured or Indicated; 1.4Moz Au and 62kt Cu

§ Group Mineral Resources (including Havieron) increases by >40%, with 285Mt @ 1.11g/t Au and 0.14% Cu for 10.2Moz Au and 387kt Cu, including:

‒    Measured: 10.3Mt @ 0.68g/t Au and 0.07% Cu for 0.2Moz Au and 7kt Cu

‒    Indicated: 104.7Mt @ 1.60g/t Au and 0.21% Cu for 5.4Moz Au and 221kt Cu

‒    Inferred: 170.0Mt @ 0.84g/t Au and 0.09% Cu for 4.6Moz Au and 159kt Cu

55% of contained gold comprises Measured or Indicated; 5.6Moz Au and 227kt Cu

§ Inaugural Greatland Telfer MRE delivered within just 15 weeks from completion of Greatland’s acquisition of Telfer.

§ Telfer MRE based on a gold price of A$3,450/oz (West Dome Open Pit and Stockpiles) and A$3,150/oz (Main Dome Underground), relative to current spot gold price of approximately A$4,700/oz.

§ Key activities and priorities at Telfer going forward:

‒    The 2024 Telfer MRE will form the basis of Greatland’s inaugural Telfer Ore Reserve, targeted for the June 2025 quarter.

‒    Additional drill capacity has been mobilised to site, targeting high priority infill targets (conversion of Inferred Resources to Indicated) and extension targets (Resource growth) identified during this Telfer MRE process. There are currently four drill rigs operating at site (two each within the open pit and underground respectively) with a further two drill rigs mobilising in the June 2025 quarter.

‒    Progressing the exciting new West Dome Underground Project, which recently delivered exceptional drilling results including 14.3m @ 9.6g/t and 8.57% Cu and 59.0m @ 2.83g/t Au and 0.71% Cu (refer to Greatland’s announcement on 20 February 2025 titled ‘West Dome Underground Project’).

‒    Due to the scale of the Telfer deposit and the number of areas to review, this 2024 Telfer MRE focused on the active mining areas, namely the West Dome Open Pit and the Main Dome Underground areas. Greatland will continue to evaluate the currently unclassified mineralisation including the Main Dome Open Pit, the Main Dome Underground’s Vertical Stockwork Corridor (VSC) and Eastern Stockwork Corridor (ESC), as well as several satellite deposits near Telfer, for potential to incorporate into future Telfer Mineral Resource updates.

Table 1: 2024 Group Mineral Resource Statement

Notes:

Mineral Resources are reported as at 31 December 2024, 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$3,450/oz Au and A$5.30/lb Cu for the West Dome cutback & stockpiles and A$3,150/oz and A$5.30/lb for the Main Dome underground.  Cutoffs for the Havieron Deposit Mineral Resources were also based on a NSR using metal prices of A$2,360/oz Au and A$5.20/lb Cu.

Greatland Managing Director, Shaun Day, commented:

“This inaugural Greatland Telfer Mineral Resource estimate is an outstanding result, delineating 3.2 million ounces of contained gold.  This exceptional outcome is a testament to the significant opportunities we saw at Telfer during our acquisition due diligence, and the excellent work of our team to progress and validate those opportunities in short order.

“Total group Mineral Resources now stand at more than 10.2 million ounces of gold and 387,000 tonnes of copper, an exceptional foundation for Greatland as a leading new Australian gold and copper producer.

“When we announced the acquisition, we described an initial 15-month mine plan at Telfer to produce 374,000 ounces of gold and 13,000 tonnes of copper. Our two key focuses at Telfer now are continuing safe and profitable operations and demonstration of mine life extension.

“This Telfer MRE confirms the very significant extension opportunities we see at Telfer and gives us confidence in the opportunity to extend Telfer’s mine life. This result is an important step towards a long life integrated Havieron and Telfer mining operation.

“The upcoming June 2025 quarter is a very exciting one for Greatland, in which we will report our first full quarter operating results for the March 2025 quarter, give production and costs guidance for FY2025, deliver our inaugural Telfer Ore Reserve estimate, and list on the ASX.

2024 Telfer Mineral Resource Statement

The 2024 Telfer Mineral Resource consists of two main areas: the West Dome Open Pit and the Main Dome Underground (Figure 1). Both areas are active mining operations.

Table 2: 2024 Telfer Mineral Resource Statement

Notes:

Mineral Resources are reported as at 31 December 2024, grades are reported to two decimal places to reflect appropriate precision in the estimate, and this may cause apparent discrepancies in totals. Cutoffs are applied based on a NSR using metal prices of A$3,450/oz Au and A$5.30/lb Cu for the West Dome cutback & stockpiles and A$3,150/oz and A$5.30/lb for the Main Dome underground.

Figure 1:  2024 Telfer Mineral Resources Schematic

The West Dome Open Pit is currently the primary source of ore mined at Telfer.  The 2024 Telfer MRE includes a Mineral Resource at the West Dome Open Pit of 115.6Mt @ 0.55g/t Au and 0.05% Cu, for 2.1Moz Au and 61kt Cu.

Figure 2: West Dome Open Pit Mineral Resources (Plan View, Resource by Classification)

Note: Stage 2 Extension was previously described as Stage 8 Extension.

The Stage 7 Cutback and Stage 2 Extension (Figures 2 & 3) were previously classified as Exploration Targets in Greatland’s Admission Document dated 10 September 2024. These areas have now been incorporated into the 2024 Telfer MRE. Drilling of the additional Resources outside of these previously identified extension (blue text in Figure 2 above and Figure 3 below) began in February 2025 and will continue to be a focus throughout 2025 with a second reverse circulation (RC) drill rig recently arriving on site.

Figure 3: West Dome Open Pit Mineral Resources (Plan View, Resource by Au grade)

Note: The ‘A’ / ‘B’ points and line between them correspond to the long section in Figure 4.

Figure 4: West Dome Open Pit Mineral Resources (Long Section, Resource by Au grade)

 The Telfer Main Dome Underground MRE (Figure 5 below) comprises two main areas, the Upper Mine (M Reefs) from which ore is trucked to surface and the Lower Mine (A Reef, Rey, LLU, B30) which utilises the underground haulage shaft to transport ore to surface. The M Reefs are narrow high-grade reefs, while much of the Lower Mine Resources consist of reef and stockwork corridors, resulting in relatively broad (3 – 8m) and continuous packages of mineralisation.

Two underground diamond rigs are currently onsite, focused on upgrading high priority areas of the MRE, along with testing several new near-mine targets such as the Eastern Stockwork Corridor (‘ESC’) located in the Upper Mine to the east of the M Reefs.

Figure 5:  Telfer Main Dome Underground Mineral Resources (Resource by Au grade)

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 6).  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, totaling 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 lease M45/6, M45/7, M45/8 and M45/33.

Figure 6:  Telfer mine location map

Drilling Overview

The Telfer 2024 Mineral Resource estimate (Table 2) incorporates all drilling available as at 31 December 2024 and comprises of Mineral Resources estimates from the West Dome Open Pit mine, the Main Dome Underground mine, and already mined stockpiles.

Drill hole data available for the current Mineral Resource estimates areas is largely based on drilling completed from 1998 to 2024. Drilling procedures have changed over the history of the Telfer deposit. Historical drilling adopted 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 of HQ diameter unless reduction was necessary to complete a drill hole. Early 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 (MMT).

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. 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 and large areas of low grade stockwork mineralisation.

The highest concentration of gold and copper grades occurs within bedding sub-parallel reef systems, 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.

Stockwork mineralisation is characterised by narrow, often discontinuous veins that crosscut stratigraphy. Large domains of stockwork mineralisation were defined in the open pits and within the axial zones within both the West Dome and Main Dome deposits. Stockworks are laterally extensive, between 0.1km to 1.5km scale and the geometry of the stockwork zones is related to structure and stratigraphy.

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 20 cm to 1m while RC drilling collected 1m samples, with 2-5kg sub-samples for fire assay. Recent West Dome 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 samples 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 lab or certified external labs.

Assay quality control protocols have followed evolving industry standards, with rigorous procedures including standard material submission, coarse blanks, umpire lab 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.

Telfer Mineral Resource Estimation

Both 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 stockwork mineralisation is estimated by MIK while reef and vein style mineralisation is estimated through OK. 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 2024 Telfer MRE uses:

§ Open Pit & Stockpile Metal prices of A$3,450/oz Au and A$5.30/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 80% for Au and 50% for Cu.

§ Underground: Metal prices of $3,150/oz and A$5.30/lb, with the MRE reported representing multiple mineralised lodes that have different cost profiles base on the selected mining approach. For the December 2024 MRE update the NSR cutoffs applied to the underground ranged from $46-150/tonne. The inputs to this cutoff are reviewing 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 previous Mineral Resource estimates

The previous Mineral Resource estimate for Telfer was reported by Newmont Mining Corporation as at December 2023.

Newmont reports Reserves and Resources in accordance with the U.S. Securities and Exchange Commission’s SK 1300 guidelines (SK 1300), which is different to the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, 2012 Edition (JORC). At 31 December 2023, Newmont reported a Mineral Resource estimate for Telfer of 27.6Mt @ 0.67g/t Au and 0.09% Cu for 600koz of gold and 24.8kt of copper (refer to Newmont’s 2023 Reserves & Resources Statement, available here).

Greatland reports its Mineral Resources and Ore Reserves in accordance with the JORC Code, which is an internationally recognised reporting standard for the purposes of the AIM Rules.

Following completion of its acquisition in December 2024, Greatland has reviewed previously reported Mineral Resources, identifying significant expansion to Newmont’s previous December 2023 MRE at both the West Dome Open Pit and Main Dome Underground.

This review involved the application of updated economic factors, based on current operating costs and updated metal price cut-offs of A$3,450/oz gold and A$5.30/lb copper for the West Dome Open Pit and A$3,150/oz and A$5.30/lb copper for the Main Dome Underground, relative to current spot prices of approximately A$4,700/oz gold and A$7.00/lb copper.

In the West Dome Open Pit, the Mineral Resource was previously spatially constrained by the initial 15-month Telfer mine plan that Greatland has described in connection with the acquisition of Telfer. For the 2024 Telfer MRE, Greatland has aligned with a more typical industry approach of reporting open pit Mineral Resources above a pit optimisation shell, a process which incorporates all cost and revenue assumptions to identify potentially economic material.

In the Main Dome Underground, the Mineral Resource was also previously spatially constrained by the initial 15-month Telfer mine plan. For the 2024 Telfer MRE, Greatland has conducted detailed economic evaluations (using MSO “mineable stope optimisers”) to spatially define potentially economic material, which subsequently underwent detailed geological evaluation to identify suitable material to incorporate into the MRE.

The stockpiles reported by Greatland in this 2024 Telfer MRE consist of both high grade and low-grade stockpiles, with 10.3Mt @ 0.68g/t Au and 0.07% Cu of high-grade stockpiles, and 20.3Mt @ 0.33g/t Au and 0.04% Cu of low-grade stockpiles. Telfer low grade stockpiles have been classified by Newcrest Mining Limited as Mineral Resources historically, while only a portion were classified in Newmont’s December 2023 MRE. Based on the current site costs and the evaluation of the historical processing of low-grade ore, recoveries of 78.5% for Au and 45% for Cu have been assumed for the low-grade stockpiles. The Competent Person is of the opinion that the low-grade stockpile meet the requirements to be defined as a Mineral Resource under the JORC code.

Figure 7: Telfer MRE waterfall chart showing Telfer tonnage reconciliation between Newmont’s 2023 Telfer MRE and the Greatland’s 2024 Telfer MRE

Figure 8: Telfer MRE waterfall chart showing Telfer contained gold ounces reconciliation between Newmont’s 2023 Telfer MRE and Greatland’s 2024 Telfer MRE

Group Mineral Resources Statement

Greatland’s combined group total 2024 Mineral Resource has increased to 285Mt @ 1.1g/t Au and 0.14% Cu, for 10.2Moz gold and 387kt copper, consisting of the 2024 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 since its release in December 2023, please refer to Greatland’s announcement on 21 December 2023 titled ‘Havieron Mineral Resource Estimate Update’ for further details.  

Table 3: 2024 Group Mineral Resource Statement

Notes:

Mineral Resources are reported as at 31 December 2024, 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$3,450/oz Au and A$5.30/lb Cu for the West Dome cutback & stockpiles and A$3,150/oz and A$5.30/lb for the Main Dome underground.  Cutoffs for the Havieron Deposit Mineral Resources were also based on a NSR using metal prices of A$2,360/oz Au and A$5.20/lb Cu.

Contact

For further information, please contact:

Greatland Gold plc

Shaun Day, Managing Director | Rowan Krasnoff, Head of Business Development
info@greatlandgold.com