REG - Greatland Gold PLC - 2024 Group Mineral Resource Statement
18/03/2025 07:15
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RNS Number : 0929B Greatland Gold PLC 18 March 2025
Greatland Gold plc (AIM: GGP)
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NEWS RELEASE | 18 March 2025
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
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.
Greatland Gold plc (AIM:GGP) (Greatland or the Company), 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
Area Measured Indicated Inferred Combined
Tonnes Au Cu Tonnes Au Cu% Tonnes Au Cu Tonnes Au Cu Au Cu
(Mt)
g/t
%
(Mt)
(Mt)
g/t
%
(Mt)
g/t
%
(Moz)
(kt)
Havieron Deposit - - - 50 2.60 0.33 81 1.10 0.13 131.0 1.67 0.21 7.0 270
Telfer: West Dome Open Pit - - - 28.8 0.57 0.05 86.8 0.55 0.05 115.6 0.55 0.05 2.1 61
Telfer Main Dome Underground - - - 5.6 2.65 0.56 2.3 2.55 0.39 7.9 2.62 0.51 0.7 40
Telfer Stockpiles 10.3 0.68 0.07 20.3 0.33 0.04 - - - 30.6 0.45 0.05 0.4 16
Combined 10.3 0.68 0.07 104.7 1.60 0.21 170 0.84 0.09 285 1.11 0.14 10.2 387
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
Area Measured Indicated Inferred Combined
Tonnes Au Cu Tonnes Au Cu Tonnes Au Cu Tonnes Au Cu Au Cu
(Mt)
g/t
%
(Mt)
(Mt)
g/t
%
(Mt)
g/t
%
(Moz)
(kt)
g/t %
Telfer West Dome Open Pit - - - 28.8 0.57 0.05 86.8 0.55 0.05 115.6 0.55 0.05 2.1 61
Telfer Main Dome Underground - - - 5.6 2.65 0.56 2.3 2.55 0.39 7.9 2.62 0.51 0.7 40
Telfer Stockpiles 10.3 0.68 0.07 20.3 0.33 0.04 - - - 30.6 0.45 0.05 0.4 16
Total 10.3 0.68 0.07 54.7 0.69 0.10 89 0.60 0.06 154.1 0.64 0.08 3.2 117
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
(https://s24.q4cdn.com/382246808/files/doc_earnings/2023/q4/supplemental-info/Newmont-2023-Reserves-Release.pdf)
).
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
Area Measured Indicated Inferred Combined
Tonnes Au Cu Tonnes Au Cu% Tonnes Au Cu Tonnes Au Cu Au Cu
(Mt)
g/t
%
(Mt)
(Mt)
g/t
%
(Mt)
g/t
%
(Moz)
(kt)
g/t
Havieron Deposit - - - 50 2.60 0.33 81 1.10 0.13 131.0 1.67 0.21 7.0 270
Telfer West Dome Open Pit - - - 28.8 0.57 0.05 86.8 0.55 0.05 115.6 0.55 0.05 2.1 61
Telfer Main Dome Underground - - - 5.6 2.65 0.56 2.3 2.55 0.39 7.9 2.62 0.51 0.7 40
Telfer Stockpiles 10.3 0.68 0.07 20.3 0.33 0.04 - - - 30.6 0.45 0.05 0.4 16
Combined 10.3 0.68 0.07 104.7 1.60 0.21 170 0.84 0.09 285 1.11 0.14 10.2 387
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 (mailto:info@greatlandgold.com)
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
SI Capital Limited | Nick Emerson / Sam Lomanto | +44 148 341 3500
Media Relations
Australia - Fivemark Partners | Michael Vaughan | +61 422 602 720
UK - Gracechurch Group | Harry Chathli / Alexis Gore / Henry Gamble |
+44 204 582 3500
About Greatland
Greatland is a gold and copper mining company listed on the London Stock
Exchange's AIM Market (LSE:GGP) and operates its business from Western
Australia.
The Greatland portfolio includes the 100% owned Telfer gold-copper mine, the
adjacent 100% owned world class Havieron gold-copper project (under
development), 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 of Western Australia.
Greatland is targeting a cross listing on the ASX in the June quarter 2025.
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 Persons Statement
Information in this announcement has been reviewed and approved by Mr Michael
Thomson, a Member of the Australian Institute of Geoscientists (AIG), who has
more than 20 years relevant industry experience. Mr Thomson, an employee of
the Company, has sufficient experience relevant to the style of
mineralisation, type of deposit under consideration, and to the activity which
he is undertaking to qualify as a Competent Person as defined by the 2012
Edition of the Australasian Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves (the JORC Code) and under the AIM Rules - Note for
Mining and Oil & Gas Companies, which outline standards of disclosure for
mineral projects. Mr Thomson consents to the inclusion in this announcement
of the matters based on this information in the form and context in which it
appears.
JORC Tables
JORC 2012 Table 1: Section 1 - Sampling Techniques and Data (Telfer)
Criteria Commentary
Sampling techniques Resource definition drilling at Telfer involves a combination of reverse
circulation (RC) and diamond drilling throughout the mining period. For
diamond drilling, samples are taken according to lithological boundaries, with
geologists defining sample intervals and selecting the assay methodology.
Historically, high-grade reef samples were sent for screen fire assay, while
other samples underwent fire assay for gold and additional elements.
Core sizes for resource drilling usually range from NQ to PQ, while smaller
sizes (NQ or LTK60) are used for grade control. Diamond drilling typically
samples lithological units with lengths between 0.2 to 1.2 meters, with
1-meter intervals being most common and they are barcoded and submitted for
laboratory analysis.
Historically, RC drilling typically produces 1-meter samples, from which a 2-5
kg sub-sample is taken using a riffle splitter, then pulverised for gold
assay. Earlier RC drilling involved samples from 0.5-meter to 2-meter
intervals, with the small intervals were used to target reefs. Recent RC
drilling for resource definition uses 1-meter intervals and split using cone
splitter from which a 2-5 kg sub-sample is taken with bulk reject material
stored temporarily. While grade control uses 2-meter intervals and split using
cone splitter. All RC drilling has field duplicates conducted at a 1:20 ratio.
Rock chip samples, collected manually from exposed development faces, are
typically 2-3 kg, collected perpendicular to bedding, and include all relevant
domains (reef, hanging wall, footwall). These samples are stored in
pre-numbered bags for analysis.
Drilling techniques Drilling at the Telfer has evolved over time, following industry-standard
protocols. Before 1998, drilling targeted mainly previously mined areas, while
from 1998 to 2002, diamond drilling formed the primary data source for current
Mineral Resource estimates, supplemented by RC drilling. Currently, RC
drilling is the primary data source for the open pit resources and diamond
drilling for underground resources. Currently, NQ2 is the dominant drill
size for diamond drilling and RC Drilling is drilled with a pre-collar of
143mm then reduced to 134mm diameter.
Additional core sizes, including NQ, HQ, HQ3, LTK60, and limited PQ and BQ,
have also been used at Telfer. LTK60 and BQ have mainly been used for grade
control. The Reflex orientation tool is used by drillers, with all core
being oriented using Ezy-Mark to mark the bottom of the hole. The core is then
re-constructed in V-Rail, where the orientation line is drawn along the core.
Drill sample recovery Core recovery data from diamond drilling is systematically recorded by
comparing drillers' depth blocks with database records and is stored in the
geological database. If excessive core loss occurs, a wedge hole is often
drilled to recover the lost interval. A review in 2019 confirmed no
significant relationship between sample recovery and grade for either core or
RC samples, with high core recovery minimising potential loss effects.
Following the review, weighing each RC sample at the rig was implemented to
ensure consistent sample support in resource estimation.
Logging Geological logging is conducted for all diamond and reverse circulation (RC)
drill holes, capturing lithology, alteration, mineralisation, veining, and
structure (for diamond core). Diamond drill holes are also quantitatively
logged for veining, vein percentage, and structure. All drill core is
photographed before sampling, using either slide film or digital cameras.
Logged data is validated before merging into the database, which contains over
1,000 km of logged geology, covering approximately 80% of total drilling. Rock
Quality Designation (RQD) is routinely recorded, with around 900 diamond holes
geotechnically assessed. The level of logging detail is appropriate for
resource estimation and related studies.
Sub-sampling techniques and sample preparation Sampling and quality control procedures are designed for the material being
tested. Geologists define sample intervals to avoid crossing key lithological
contacts and select appropriate assay methods. Diamond core is typically
sampled as half-core, while RC samples are collected dry, with conditions
recorded. Since 2015, cone splitters have replaced riffle splitters for RC
sampling, with field duplicates taken at a 1:20 ratio.
Core samples are processed through drying, crushing, and pulverising, with
historical standards requiring 90% passing 75 µm. Older RC drilling used
0.5-2 m intervals, while recent resource definition drilling follows 1 m
intervals (2 m for grade control), with a 5 kg primary split collected.
Samples are prepared at the Telfer lab, where they are crushed, sub-split, and
pulverised to 95% passing 106 µm. Gold is analysed via 30 g fire assay, while
base metals, sulphur, and arsenic are tested by ICP. Cyanide-soluble copper is
determined by bottle roll leach with AAS analysis. To ensure accuracy, 1 in 20
samples undergo external lab verification.
Quality of assay data and laboratory tests Assay and quality control protocols at the Telfer deposit have evolved to
align with industry standards. Before 1998, quality control procedures
followed industry norms of the time, with no major concerns identified. From
1998 onwards, protocols were enhanced, particularly during prefeasibility and
feasibility studies conducted between 1998 and 2002.
Samples are primarily prepared at the Telfer laboratory and then sent to
external commercial labs for analysis. Currently, all resource definition
samples have been assayed through a combination of the Telfer Laboratory and
the Bureau Veritas (BV) Commercial Lab in Perth and all grade control samples
have been sent through Telfer Laboratory. Gold is analysed using fire assay,
while multi-element analyses-including silver, arsenic, bismuth, copper, iron,
nickel, lead, sulphur, and zinc-are conducted using ICP techniques.
Cyanide-soluble copper is assessed via bottle roll leach with AAS analysis.
Since 1998, comprehensive quality control measures have been in place,
including the use of Certified Reference Materials (CRMs), blanks, duplicate
assays, blind pulp re-submissions and checks at independent laboratories.
Matrix-matched CRMs were introduced in 1999, and transition to multi client
CRMs in 2018. Since 2000, Telfer's laboratory was managed by commercial
organisations until Telfer re-opening in 2002 has been managed by Newcrest and
now, Greatland.
Regular reviews of Quality Assurance and Quality Control (QAQC) procedures,
including sample resubmissions and bias assessments, help ensure data accuracy
and reliability. Monthly reports document any anomalies, with corrective
actions taken as needed. Comparison studies, including analyses of duplicate
pulp samples sent to external laboratories, confirm data precision, with a 90%
repeatability rate. The QAQC protocols and assay techniques used are
considered reliable for Mineral Resource estimation.
During the 2002 feasibility study, 13,570 pulp duplicate samples were
dispatched from the Telfer preparation laboratory for analysis at a check
laboratory. Insignificant bias was identified between the original and check
laboratories for gold (-0.8%) and copper (0.5%).
Verification of sampling and assaying Drill hole data is securely stored in an acQuire database, with stringent
controls to ensure data integrity and prevent errors or duplication. Data
collection, including collar coordinates, drill hole designation, logging, and
assaying, follows strict protocols to maintain accuracy. Validation involves
multiple stages, with input from geologists, surveyors, assay laboratories,
and down-hole surveyors where applicable.
Data entry has evolved from manual methods to direct digital input,
incorporating automated validation checks. Internal and external reviews
further enhance data quality before resource estimation. Resource data is
managed daily by site geologists, with additional verification by a
centralised resource team.
Sampling details are recorded digitally, utilising barcode and tracking
systems to monitor sample integrity throughout the process. Recent drilling
programs employ numbered bags for tracking consistency. Regular audits of both
internal and commercial laboratories ensure compliance with quality standards.
No assay data adjustments have been made in the Mineral Resource estimate.
Location of data points Mining operations at Telfer Gold Mine adhere to periodic reporting
requirements for the WA Department of Mines, Industry Regulation and Safety
(DMIRS), using the MGA94/AHD coordinate system for official submissions.
However, site operations utilise the Telfer Mine Grid (TMG) and Telfer Height
Datum (THD), requiring coordinate transformations between the national and
operational coordinate systems.
This has been supplied by AAM Surveys in 1995 (AMG84 to Telfer Mine Grid) and
AAMHATCH in February 2007 (Telfer Mine Grid to MGA Transformation). Both
reports also addressed the height datum and in 2007 established the THD=AHD +
5193.7m.
A local grid covers the whole of the Telfer mine area (Telfer Mine Grid 2002).
It is oriented with grid north at 44o03'12' west of magnetic north.
Topographic control is maintained through a combination of surface and aerial
surveys, with routine updates for pits and underground voids. Drill hole
collars are surveyed upon completion by mine surveyors. The natural surface
topography, along with current pit surveys and underground voids (development,
stopes and vertical openings) are used to deplete the resources and account
for changes in mining areas at Telfer.
Downhole survey methods have evolved over time, progressing from early
single-shot cameras to modern electronic tools. Currently, drilling programs
include multi-shot surveys at regular intervals, with post-completion surveys
conducted at finer resolutions. Specific drilling campaigns may incorporate
gyroscopic surveys where required. Routine in-pit drilling, particularly for
pre-production and grade control, typically excludes downhole surveys, relying
on collar surveys for accuracy.
Data spacing and distribution The drill hole spacing is sufficient to demonstrate geological continuity
appropriate for the Mineral Resource and the classifications applied under the
2012 JORC Code.
The drill spacing applied to specific domains within the overall resource is
variable and is considered suitable for the style of mineralisation and
mineral resource estimation requirements.
Orientation of data in relation to geological structure The Telfer mine site topography is dominated by two large scale asymmetric
dome structures with steep west dipping axial planes. Main Dome is in the
southeast portion of the mine and is exposed over a strike distance of 3 km
north-south and 2 km east-west before plunging under transported cover. West
Dome forms the topographical high in the northwest quadrant of the mine and
has similar dimensions to Main Dome. Both fold structures have shallow to
moderately dipping western limbs and moderate to steep dipping eastern limbs.
Surface drilling is orientated to ensure optimal intersection angle for the
reefs. Underground drilling orientation may be limited by available collar
locations, but acceptable intersection angles are considered during the drill
hole planning process. No orientation bias has been indicated in the
drilling data..
Sample security Sample security is maintained through a tracking system from drilling to
database entry. While barcoding was previously used, it has been replaced with
pre-numbered calico bags for resource development and underground drilling
samples.
All sample movements, including dispatch details, drill hole identification,
sample ranges, and analytical requests, are recorded in a database. Any
discrepancies identified upon receipt by the laboratory are validated to
ensure data integrity.
Audits or reviews In-house reviews of data, QAQC results, sampling protocols and compliance with
corporate and site protocols are carried out at various frequencies by company
employees not closely associated with the Telfer projects. Procedure audits
and reviews are carried out by corporate employees during site visits.
JORC 2012 Table 1: Section 2- Reporting of Exploration Results (Telfer)
Criteria Commentary
Mineral tenement and land tenure status 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.
Exploration done by other parties 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.
Geology 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
Drill hole Information Not applicable to the mineral resource estimate.
Data aggregation methods 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.
Relationship between mineralisation widths and intercept lengths 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.
Diagrams As provided
Balanced reporting 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.
Other substantive exploration data Not applicable to the mineral resource estimate.
Further work Further work is planned to evaluate exploration opportunities that extend the
known mineralisation and to improve confidence of the model.
JORC 2012 Table 1: Section 3 - Estimation and Reporting of Mineral Resources
(Telfer)
Criteria Commentary
Database integrity Data is stored in a SQL Server database known as acQuire. Assay data and
geological data are electronically loaded into acQuire and the database is
replicated in Greatlands centralised database system. Regular reviews of data
quality are conducted by site and corporate teams prior to resource
estimation.
Validation checks include but are not limited to:
· Duplicate drill hole identifier.
· Overlapping FROM and TO intervals values in the geology,
oxidation state, assay, density, core size, and recovery tables.
· Duplicate records.
· Other checks made outside the SQL environment include but are not
limited to:
· Down hole survey dip and bearing angles appear reasonable.
· All collar co-ordinates were within the permit area.
· Any anomalous assay, density or sample recovery values.
Site visits The Competent Person for Telfer Mineral Resources regularly visits the site.
Geological interpretation 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
Dimensions The maximum extent of the Telfer Mineral Resource is approximately 5 km x 1.5
km x 1.8km over the two dome complexes.
Estimation and modelling techniques 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.
Moisture All tonnages are calculated and reported on a dry tonne basis.
Cut-off parameters 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.
Mining factors or assumptions 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
Metallurgical factors or assumptions 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.
Environmental factors or assumptions 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 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.
Classification 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.
Audits or reviews. 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.
Discussion of relative accuracy/ confidence 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.
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