Mining and ore processing at Telfer operate under granted leases and licenses covering all key infrastructure, including open pits, underground resources, processing facilities, waste storage, and support services. The Telfer Main Dome Underground Mineral Resource is within mining leases M45/6 and M45/8, while the West Dome Mineral Resource, approximately 3km northwest of the Main Dome open pit, lies within leases M45/7 and M45/33. These leases are currently under renewal.

An Indigenous Land Use Agreement (ILUA) has been in place since December 2015, covering all operational aspects of the site. Telfer operations also remain compliant with the Mining Rehabilitation Fund (MRF) levy.

The Telfer district was first geologically mapped by the Bureau of Mineral Resources in 1959, though no gold or copper mineralization was identified. In 1971, regional sampling by Day Dawn Minerals NL detected anomalous copper and gold at Main Dome. From 1972 to 1975, Newmont Pty Ltd conducted extensive exploration and drilling, defining an open pit reserve primarily in the Middle Vale Reef.

In 1975, BHP Gold acquired a 30% stake in the project, and in 1990, Newmont and BHP Gold merged their Australian assets to form Newcrest Mining Limited. Newcrest managed exploration and resource drilling from 1990 until its acquisition by Newmont Corp on November 6, 2023. Newmont later divested Telfer, selling it to Greatland Gold on December 4, 2024, which now oversees exploration and drilling activities.

Telfer is located within the northwestern Paterson Orogen and is hosted by the Yeneena Supergroup, a 9 km thick sequence of marine sedimentary rocks. Gold and copper mineralization occurs in stratiform reefs and stockworks within the Malu Formation of the Lamil Group, controlled by both structure and lithology.

Mineralisation styles include high-grade narrow reefs, reef stockwork corridors, sheeted vein sets, and extensive low-grade stockwork, which forms most of the sulphide resource. Sulphide mineralisation consists mainly of pyrite and chalcopyrite, with copper minerals including chalcopyrite, chalcocite, and bornite. Gold is primarily free-grained or associated with sulphides and quartz/dolomite gangue, with a correlation between vein density and gold grade.

The highest gold and copper grades occur within bedding sub-parallel reef systems, including multiple reef structures in Main Dome, such as E-Reefs, MVR, M10-M70 reefs, A-Reef, and B-Reefs (notably B30). Additional mineralisation occurs in northwest-trending and north-dipping veins. Stockwork mineralisation, found in open pits, Telfer Deeps, and the Vertical Stockwork Corridor (VSC), is best developed in the axial zones of Main Dome and West Dome, often extending over large areas (0.1 km to 1.5 km). It can include brecciated zones filled with quartz, carbonate, and sulphides

Not applicable to the mineral resource estimate.

Significant assay intercepts are reported using length-weighted averages based on predefined thresholds, with a maximum allowable internal dilution. For Mineral Resource estimates, data aggregation methods are aligned with sampling, drilling, and recovery techniques. No exploration results are included in this report, as it focuses on Ore Reserves and Mineral Resources.

No exploration has been reported in this release, therefore there are no relationships between mineralisation widths and intercept lengths to report. This section is not relevant to this report on Ore Reserves and Mineral Resources.

As provided

Significant assay intervals represent apparent widths, as drilling is not always perpendicular to the dip of mineralisation. True widths are typically less than downhole widths and can only be estimated once all results are received and final geological interpretations are completed. No exploration results are included in this report, so relationships between mineralisation widths and intercept lengths are not applicable to the Ore Reserves and Mineral Resources report.

Not applicable to the mineral resource estimate.

Further work is planned to evaluate exploration opportunities that extend the known mineralisation and to improve confidence of the model.

The Competent Person for Telfer Mineral Resources regularly visits the site.

All interpretations were undertaken by site-based geologists.

MDU Block Model

The MDU Block Model wireframe interpretations were constructed in Leapfrog software using implicit modelling interpolations from primary logging codes extracted from the Acquire database. The Main Dome Underground model includes the Lower M-Reef horizons (from M52 downward), the A Reefs horizons,, Kylo, B30 Reef, LLU, Rey LLU and Rey AR, Oakover Vein, Wedge, North Finn and intervening Stockwork mineralisation. 

The Lower M Reefs comprise both intermittent reef but more significantly zones of stockwork mineralisation, as such each of these are modelled as mineralised corridors. The same approach has been applied to the A Reef interpretation with multiple corridors of reef and stockwork mineralisation defined.

Kylo also comprise high-grade mineralised breccia\stockwork and is stratabound.

The LLU is a mineralised stratigraphic layer that is guided by the well know dome-shaped stratigraphy in Main Dome and monocline structure.  The western limb of the LLU has been the target of bulk stoping in mining areas called Western Flanks.

In the south-eastern of the lower mine, thrust structures have been identified that offset and dilate the eastern limb stratigraphy. High-grade veining has formed in the dilation zone and two domains have been interpreted to capture this mineralisation Rey LLU and Rey A-Reefs.

M-Reef Block Model

The Upper M Reefs (M20 to M50) are largely strataform, interpretation is guided by the well-known dome shape stratigraphy. The Upper M-Reef mineral resource consists of discrete reef wireframes constructed in Vulcan using Sirovision mapping, wall mapping and sampling data from development drives, and from drill hole intercepts.  The thickness of the reef is honoured as far as practicable in the interpretation process.

West Dome Block Model

The Telfer West Dome Deposit consists of a repeat of the Main Dome geological units. Mineralisation styles include high-grade narrow reefs, reef stockwork corridors, sheeted vein sets, and extensive low-grade stockwork, which forms most of the sulphide resource.

The primary estimation domains are based on stratigraphy. The estimates refrained from detailed interpretations of E-Reefs as they are discontinuous and complex to interpret. The estimate relies on an E-Reef corridor within the appropriate stratigraphy to constrain grade estimation.

The M-Reefs domains in West Dome they have been interpreted as reef/stockwork corridors from drill hole intercepts.  The thickness of the reef is honoured as far as practicable in the interpretation process and within the database, defined by intercept domains. The M-Reefs are largely strataform, interpretation is guided by the well-known dome shape stratigraphy.

 The Leeder Hill Veins are sub-vertical veins sets that run west to east across the West Dome Resource.  They vary in thickness from 1 -10cm in thickness and can appear as individual veins or vein sets.

Stockwork mineralisation is best developed in the axial zones of West Dome, often extending over large areas (0.1 km to 1.5 km). It can include brecciated zones filled with quartz, carbonate, and sulphides

Main Dome Underground Block Model:

Drill data used for the MDU Resource estimate include underground diamond drilling and resource definition reverse circulation drilling.

Three composite databases were compiled for each element from the raw assay database using 4 m composite lengths for bulk domains and 2m composite length for more discrete domains like Lower M-Reefs, A-Reefs, Kylo and Rey Domains and copper specific 4m composite that's coded for copper. The databases use all available resource definition drill data and the 3-D wireframes from the interpreted geological model. The majority of the raw assay file contains 1 or 2 m assay intervals.

Boundary contact analyses were undertaken on all stratigraphic and mineralised domains. The result of this analysis forms the basis for the majority of the stockwork sub-domaining decisions for the project. The analyses were conducted using both the 4 m and 2m downhole composites for gold and copper. The boundary analyses for both elements (Au and Cu) reveal that most of the domain boundaries are hard and are accordingly estimated independently.

Exploratory data analysis was undertaken on the bulk and discrete domains with 4m and 2m composite data for gold, copper, sulphur, arsenic, and cobalt assessed. Statistical reviews indicate that Stockwork domains have highly variable distributions. The other domains contain lower variable distributions due to their more homogeneous mineralisation style.  

Due to the generally lower variability, it was decided to use OK for all other domains except for stockwork

Ordinary Kriging is considered to be sub-optimal for estimating in highly variable material without the need for aggressive top-cuts, due to the potential over-representation of the extreme end of the data distribution.  A non-linear method such as Multiple Indicator Kriging (MIK) is considered to be better suited for dealing with these highly variable data sets. MIK was used to estimate gold and copper grade in the majority of stockwork domains. The MIK estimate is e-type that directly estimates the model blocks with the average grade of the cumulative distribution.

Top cutting (capping) was applied where appropriate for the OK estimations. Metal at risk analysis was completed to inform the capping grades.

The non-economic elements are all estimated by ordinary kriging in all domains. Cyanide soluble copper, sulphur, arsenic and cobalt variogram models were generated by transforming the data to Gaussian space and back transforming the resulting variogram model to raw space, as no robust experimental variography could be obtained in raw space alone.  All sills have been normalised to 1.

The local varying anisotropy (LVA) rotation functionality provided by Vulcan was used during OK and MIK estimation for the A-Reefs, LLU and B30 domains.  For each target block, a unique rotation can be set and used to control both the variogram model and search neighbourhood rotation. These orientations are derived from smoothed interpretations of the main stratigraphic surfaces that define the overall geometry of the Main Dome anticline as applied to the stratigraphically aligned mineralisation.

Upper M-Reef Block Models

Modelling of the reef volume / thickness for all reefs was determined using a calculated hanging wall surface from reef domain intercepts. The vertical and true width were determined using a dynamic anisotropy model of the footwall and determining the reef dip and azimuth and calculating a vertical width and true width.

Drill data used for the estimate included underground diamond drilling, resource definition reverse circulation drilling and underground production face samples with interpreted resource definition mineralisation surfaces.

Grade composites were determined by vertical reef grade accumulates as the reef thickness varies between 0.01 m to approximately 2.0 m therefore a single composite was generated for each reef intercept. Grade accumulates were generated for gold, copper, cyanide soluble copper and sulphur, silver, arsenic, cobalt and lead and determined by grade x width. The data was then transformed into 2 dimensions and projected to a planar surface.

Exploratory data analysis (EDA) and variography analysis was conducted

Grade sensitivity tests were completed for each metal accumulate for each reef and a high- and low-grade indicator was determined for the majority of the reefs and elements. The composite files were then flagged for the indicators and indicator variograms compiled. An Ordinary Kriged indicator model was estimated and for each reef estimation block, a high grade and low-grade proportion determined.

Variogram analysis for the metal accumulates was completed at the indicator thresholds along with a review of the metal at risk for each reef and element. Gold mineralisation anisotropy is consistent for all the reefs aligned northeast, whereas copper, cyanide soluble copper and sulphur is less consistent between reefs and can lie along either the northeast trend similar to the gold trend or to the northwest along the dome hinge axis.  

Ordinary Kriging was used for estimation of the metal accumulates in 2D space for both the high- and low-grade indicator domains for each reef. Then using the high grade and low-grade block proportions, an overall grade was determined for each block estimate for each element.

Block grade estimates were then translated back into 3-dimensional resource block models defined by the footwall and hanging wall surfaces of the reef. The 2022 resource block dimensions and M20 Jan 25 resource block dimensions are 0.5 x 0.5 x 0.2 m to eliminate volume variances that can exist when reporting a narrow reef at larger block sizes. 

West Dome Open Pit Block Model

The West Dome Open Pit Resource model includes estimates for gold, copper and density along with attributes required for modelling metallurgical recovery including cyanide soluble copper, sulphur, cobalt and arsenic.

A composite database was compiled for each element from the raw assay database using 4 m composite lengths using the available resource definition drill data and the 3-D wireframes from the geological model. Many of the wireframe volumes overlap, reflecting the overprinting nature of various mineralising events at Telfer. A priority sequence was developed whereby the main mineralised reef structures were prioritised over bulk domains and background stockwork mineralisation. The majority of the raw assay file contains 1 or 2 m assay intervals. The composite length of 4 m was chosen to standardise sample support and reflects the minimum Z sub-cell size (mining selectivity in the reef corridor areas).

Boundary contact analyses were undertaken on all stratigraphic, oxidation and mineralised reef domains. The results of this analysis forms the basis for the majority of the stockwork sub-domaining decisions for the project. The analyses were conducted using the 4 m downhole composites for gold, copper and sulphur grade.

The West Dome Mineral Resource grade model is constructed with two components: Stockwork domains (bounded by key stratigraphy contacts) and Reef\Stockwork Corridor domains. The Telfer Reefs (M-Reefs) are stratabound and have relatively uniform thickness over short range intervals. Grade distribution within the reefs is also relatively consistent with regionally separated areas of on average high or low grades. Grade partitions are used to domain the reefs into high-grade and low-grade domains using an indicator estimation methodology.

The West Dome M-Reef Stockwork Corridors use ordinary kriging into the 3D solid utilising local rotation functionality (LVA) in Vulcan. Variography and estimation parameters were updated based on the revised interpretation of the mineralisation style.

The stockwork gold mineralisation outside the reefs is highly positively skewed with high Coefficient of Variation of between ~ 2 and 4. Ordinary Kriging (OK) has been demonstrated to be sub-optimal for estimating such highly variable material. Multiple Indicator Kriging (MIK) is considered best suited for this type of mineralisation. Gold and copper were estimated using MIK. The type of MIK is the e-type estimate; that is directly estimating the model blocks with the average grade of the cumulative indicator distribution. Indicator variograms for gold and copper were modelled for all Stockwork domains.

The indicator thresholds were selected such that each bin has a reducing balance of number of samples. Indicator variography was then undertaken on gold and copper ensuring that nuggets increased and ranges decreased consistently in modelling progressively higher cut-offs; this minimises order relational problems in the MIK estimates.

Stockwork cyanide soluble copper, sulphur, arsenic and cobalt stockwork estimates were estimated using Ordinary Kriging. Cyanide soluble copper, sulphur, arsenic and cobalt variogram models were generated by transforming the data to Gaussian space and back-transforming the resulting variogram model to raw space.

The local rotation (LVA) functionality provided by Vulcan was used during stockwork OK and MIK estimation.  For each target block, a unique rotation can be set and used to control both the variogram model and search neighbourhood rotation. These orientations are derived from smoothed interpretations of the main stratigraphic surfaces that define the overall geometry of the West Dome anticline as applied to the stratigraphically aligned mineralisation.

The block sizes in the resource models are 3.125 m x 3.125 m x 1 m for the selective reef areas and 12.5 m x 12.5 m x 12 m for the bulk stockwork. All modelling and estimation are done in commercially available software supplemented with specialised algorithms coded within the package as required.

All tonnages are calculated and reported on a dry tonne basis.

In both the open pit and underground, a specific cut-off grade was not used. Each block within the resource model is assigned a value based on an estimate of its net smelter return. Net smelter return is calculated on a payable metal basis taking into account metal prices, metallurgical recoveries, processing costs and realisation costs. Value / profit cut-off includes mining costs, processing costs with assigned sustaining capital and G&A components.

Consequently for stockpiled material, the material is estimated based on the Grade Control criteria at the time of production.

The LLU, B30, Kylo, and Rey resource areas will be mined using bulk stope mining, while the M20-M50 and A50-A80 areas will be mined using selective narrow vein techniques. Resource estimates have been constrained by MSO outlines to enhance mining feasibility. Fit-for-purpose models have been developed for these methods, though future technological advancements may enable alternative mining approaches.

Open-pit operations at Telfer use an excavator-loader fleet for selective ore extraction, employing a 12 m bench height mined in 4 m flitches to minimise ore dilution and loss. Bulk waste is removed in either a single 12 m pass or three 4 m flitches. The Selective Mining Unit (SMU) is defined as 6.25 m x 6.25 m x 4.00 m, ensuring dilution control without additional mining dilution or recovery factors applied to the resource estimate. The West Dome Mineral Resource shells are constrained based on contract mining costs and value NSR assessments

The current Telfer plant has been operating since 2003.

The feed ore for the Telfer treatment plant is sourced from both open pit and underground mining operations. Owing to the range of ore types with differing mineralisation of both gold and copper, together with variation in ore hardness, the treatment flowsheet is complex. Two parallel process trains have been incorporated through the grinding and flotation circuits in the treatment plant which has a nominal throughput capacity of 20 Mtpa but the throughput rate varies between 17 Mtpa and 23 Mtpa dependent upon the ore characteristics. The typical operating strategy is to blend ore to control ore grade and hardness.

The circuit was designed to maximise the recovery of the valuable minerals, with a flash flotation and gravity recovery section within the grinding circuit to capture coarse gold. The milled product passes to the copper flotation circuit where copper sulphides are recovered together with attached gold and independently liberated gold particles. Tailings from the copper circuit are processed through the pyrite flotation circuit with recovered pyrite processed through a cyanidation leach circuit for final gold extraction.

The gold is extracted from the leach liquor by means of adsorption onto activated carbon followed by stripping and electrowinning.  Two products are generated - gold dore (gravity and pyrite float leach) and gold-bearing copper concentrate.  Minor amounts of oxide ore are processed in a dump leach operation as an adjunct to the main treatment route, with the dump leach output being incorporated within the overall gold dore production total.

Metallurgical recovery formulae are applied in the value estimations developed from production history and reconciliations for each deposit. Typically, gold and copper recoveries are a function of absolute gold grade, copper grade and copper/sulphur and cyanide soluble/copper ratios to estimate either recovered grade or estimated tails grades. Transport costs and realisation costs (TCRC) of recovered metals plus smelting and royalty costs contribute to the estimated block value.

Telfer has a long history of mining and processing ore with the waste dump and residue disposal facilities all currently in place in accordance with the required statutory approvals. Statutory approvals under the Western Australian Environmental Protection Act (EP Act) provide the umbrella approval for the project. These approvals are reflected in Ministerial Approvals (issued by the Minister for the Environment - Nos. 605 and 606). The approvals include both environmental commitments made by Newcrest and conditions applied by the Minister acting primarily on the recommendations of the Environmental Protection Authority (EPA), which coordinated detailed assessment by government agencies of potential environmental impacts and proponent-proposed management plans to manage those impacts.

Performance against Ministerial Approval conditions is reported on a regular basis and reviewed by the government.

Bulk density measurements at Telfer are taken from 20 cm samples of DDH whole core using the air-water method, with results stored in the acQuire database. These measurements are conducted at nominal 20 m intervals and are assigned to stratigraphic units and there oxidation/weathering profiles. Bulk densities were extensively evaluated in the 2002 feasibility study and continue to be re-evaluated and updated based on new data.

Certain domains, such as the reef domains, MVR, LLU, and Oakover, show greater density variability due to high sulphide content, leading to bimodal distributions in some areas and sulphur regression are used for these domains.

Density estimation follows a three-step process:

1.     Global mean densities are assigned to bulk domains with low variability.

2.     Sulphur regression is used to estimate density in the LLU, where density variability is high due to sulphide content.

3.   M-Reef densities are assigned based on previous resource estimates from 2011 and 2013.

MDU:

Resource classification is based on geological interpretation confidence combined with Ordinary Kriging derived Slope of Regression (SoR) and/or Average weighted distance (AWD) of informing composites.

Typical Indicated classification (SoR) >0.65 and Inferred classification is based on SoR >0.5 on a block-by-block basis. However final classification is based on manually interpreted aggregated volumes, not individual blocks.

There are no Measured Mineral Resources.

M-Reef

Maximum drill spacing up to 40 m by 40 m with development sampling was classified as Indicated Mineral Resources. Indicated Mineral Resources must also have a sound geological understanding and grade continuity.

Where drill density and development sampling are satisfied but unsolved geological complexity exists, for example, the steeper zones of M30, M40 and M50, these were classified as Inferred.

Where drill spacing is greater than 40 m X by 40 m Y and up to100 m X by 100 m Y where unresolved geological complexity exists have been classified as Inferred Mineral Resources.

Mineralisation with drill spacing wider than 100 m X by 100 m Y is unclassified.

The primary reef M30 and M40 resource classification was used for the two double reefs M28/M30 and M38/M40.

There are no Measured Mineral Resources in the M-Reefs.

West Dome

The December 2024 West Dome Mineral Resource reported figures were classified using a combination of geostatistical confidence parameters including average weighted distance for informing samples and slope of regression resulting from the Ordinary Kriging estimation for each block. Contiguous volumes were flagged with either Indicated or Inferred classification, no in-situ material is classified as Measured.

Measured Resources at Telfer open pits are stockpiled material which has been grade controlled by very closed spaced production blast hole and/or RC sample data.

All mineral resources at Telfer are regularly independently reviewed by resource estimation specialist consultants.  The results and recommendations are tabulated and actioned by Telfer Resource Geologists.

Telfer Gold Mine is an established operation with a long history to support development of plans to exploit the available Mineral Resources.  As such, in the Competent Persons opinion, there are no known factors related to the environment, permitting, legal, title, taxation, socio-economic, marketing or political changes that could materially affect the Mineral Resource estimates. The Mineral Resource estimates are based on long term capital and operating costs assumptions based on the current operating cost base modified for changing activity levels and reasonable cost base reductions over the life of the mine.

Any material change in long term cost base or metal price assumptions would impact the Mineral Resource estimate.