MRE Update - Werumata Limestone Project
Released
Released
Announcement PDF
15 October 2026
WERUMATA RESOURCE UPGRADE DELIVERS 274MT
INDICATED LIMESTONE RESOURCE
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HIGHLIGHTS
• Significant resource classification upgrade at Werumata, with approximately 51% of the
updated Mineral Resource now Indicated, compared with the entirely Inferred maiden MRE
announced earlier this year1
.
• 274Mt Indicated Resource at 84.7% Acid Neutralisation Capacity (ANC), representing
approximately 70% of the higher-quality Product 1 limestone resource.
• Updated total Mineral Resource of 533Mt, comprising 274Mt Indicated and 259Mt Inferred,
including 391Mt of Product 1 limestone at 83.9% ANC.
• Expanded bulk density program supports the upgrade to Indicated classification,
addressing the key data limitation identified in the maiden MRE.
• Werumata retains a substantial 533Mt resource, with the reduction from the maiden MRE of
621Mt solely due to changes in estimated bulk densities; the modelled mineralised volume is
unchanged.
Estrella Resources Limited (ASX: ESR) (Estrella or the Company) is pleased to announce a significant
classification upgrade to the Mineral Resource Estimate (MRE) at its Werumata Limestone Project
located in the Lautém Municipality of Timor-Leste, with approximately 51% of the updated resource now
classified as Indicated.
The updated MRE comprises 274Mt Indicated and 259Mt Inferred, for a total central estimate of 533Mt.
This represents a substantial increase in resource confidence from the maiden MRE announced on 14
May 2026, which was classified entirely as Inferred.
The upgrade is particularly significant for Product 1, the higher-quality limestone identified for acid
neutralisation, with approximately 70% of its 391Mt resource now Indicated. The expanded bulk density
program has addressed the principal data limitation identified in the maiden estimate, providing greater
confidence in the resource classification.
Werumata retains a substantial resource base. The reduction in the total central estimate from 621Mt
to 533Mt is solely attributable to changes in estimated bulk densities, with no reduction in the modelled
1 Refer to ESR ASX announcement dated 14 May 2026
ASX: ESR
mineralised volume. Product 1 estimated tonnage has decreased from 493Mt to 391Mt while Product 3
estimated tonnage has increased from 95Mt to 109Mt. Product 2 estimated tonnage remains
unchanged.
The increase in Indicated Resources provides a stronger technical foundation for progressing
development studies and evaluating potential production scenarios, particularly for the higher-quality
Product 1 limestone.
Commenting on the upgraded Mineral Resource Estimate, Managing Director Robert Mencel said:
“This is an important milestone for Werumata, with just over half of the Mineral Resource now classified as
Indicated, including approximately 70% of our higher-quality Product 1 limestone.
“The upgrade provides greater confidence in the resource and a stronger foundation as we progress
discussions with potential customers and evaluate development and export opportunities.
“With a substantial limestone resource now supported by an improved level of geological confidence, our focus
is on advancing the technical and commercial work required to unlock Werumata's potential.”
Updated Mineral Resource
The updated Mineral Resource is effective as at 15 October 2026 and was prepared by ASEAMCO
Pty Ltd (Project 26244), with Robert de Jongh FAusIMM acting as the Competent Person for Mineral
Resource estimation.
Table 1 Updated resource by product and classification
Estimate and category Product 1
Mt
Product 2
Mt
Product 3
Mt
Total
Mt
Lower Indicated 250 - - 250
Lower Inferred 110 31 91 232
Lower Total Estimate 360 31 91 482
Central Indicated 274 - - 274
Central Inferred 117 33 109 259
Central Total Estimate 391 33 109 533
Upper Indicated 299 - - 299
Upper Inferred 124 35 127 286
Upper Total Estimate 423 35 127 585
Product 1: ANC ≥47%; Product 2: ANC 20–47%; Product 3: ANC <20%. Lower and upper estimates reflect domain-specific bulk
density variation and are not additional resources. Resources are reported on a dry basis with the report’s 97% recovery factor to
account for voids. Totals may differ due to rounding. No Measured Resource or Ore Reserve is reported.
Density program and classification upgrade
The maiden MRE relied on laboratory bulk density measurements covering less than 3% of diamond
drill core length, limiting the entire resource to Inferred classification. An expanded bulk density program
was subsequently undertaken on existing drill core, with measurements independently verified and
audited by the Competent Person.
Areas with sufficient geological, assay and bulk density information have been classified as Indicated,
while areas with wider data spacing and the remaining horizons retain an Inferred classification.
Table 2 Estimated bulk densities used in the resource models
Horizon Maiden
t/bcm
Updated
t/bcm
Updated category
BCUH 1.88 1.69 Indicated and Inferred
BPUH 1.64 1.07 Indicated and Inferred
BCUL 1.58 1.58 Inferred
LCL 1.54 1.54 Inferred
BPUX 1.53 1.53 Inferred
BPUL 1.56 1.56 Inferred
CL 1.30 1.51 Inferred
t/bcm = tonnes per bank cubic metre.
Figure 1: Interpreted Horizons
Explanatory text and figure extracted from Mineral Resource Estimate Report
Resource estimation summary
The estimate uses the original 33 reverse circulation holes (2,804m) and nine diamond holes (913m).
All holes were vertical and ranged from 41m to 140m deep. RC samples were collected at one-metre
intervals and analysed by XRF fusion at PT Geoservices, Jakarta. The Competent Person visited the
site on 23–25 November 2025.
Seven sub-horizontal limestone horizons were modelled using established geological and geostatistical
estimation methods. The models were constrained by geological boundaries, outcrops and the
concession boundary, with the existing product thresholds and 97% void recovery factor retained.
this figure.
The report’s lower and upper total estimates are 482Mt and 585Mt, including 250Mt and 299Mt Indicated
respectively. These reflect domain-specific density variation around the 533Mt central estimate and are
not additional resources. Further sampling, estimation and classification details are disclosed in JORC
Table 1 below.
Indicated and Inferred resource classification
The updated maps show that higher-confidence resource areas lie within the BCUH and BPUH
horizons. Blue denotes Indicated and green denotes Inferred. The source legends include Measured,
but no Measured Resource is reported.
Figure 2: BCUH (left) and BPUH (right) resource classification polygons and drillholes.
The updated classification is restricted to areas supported by both chemical assays and verified physical
bulk density measurements. Peripheral areas with wider data spacing remain Inferred.
Geological model and project context
Figure 3: Cross sections 1 and 2 through the geological model.
Werumata is located approximately 170km east-northeast of Dili in Timor-Leste’s Lautém Municipality
and is accessible by sealed all-weather roads. It is held by Estrella Resources Ltd Representação
Permanente, a wholly-owned subsidiary, under an Exploration and Evaluation Concession awarded for
four years from 14 May 2025.
Mineralisation occurs in the Baucau Limestone Formation and underlying Batu Putih Chalk, with
average modelled thicknesses of approximately 30m and 26m respectively. Product 1 is identified for
acid neutralisation; Product 2 for potential AAC blocks, masonry mortar and cement blending; and
Product 3 for aggregate, road base and fill. Product specifications and commercial viability require
further evaluation.
Products
• Product 1 – Acid neutralisation: Higher-quality limestone (ANC ≥47%; updated average 83.9%
ANC), identified for potential agricultural and industrial acid neutralisation applications.
Approximately 70% of its 391Mt resource is now Indicated.
• Product 2 – Industrial uses: Lower-ANC limestone (ANC 20–47%; average CaCO₃ 30.4%),
with potential applications in AAC blocks, masonry mortar and Portland cement blending.
• Product 3 – Road base and rock fill: Higher-silica material (ANC <20%; average SiO₂ 58.2%),
with potential uses in road paving, construction aggregate, road base and rock fill.
The technical report identifies open cut mining as the only economically feasible extraction method. All
three products are direct shipping ores requiring only crushing and screening with no further
metallurgical processing. Product specifications and processing requirements remain subject to
technical and customer confirmation.
Regional market opportunities
Limestone of this quality has a broad range of potential end uses, providing Estrella with multiple market
opportunities:
• Acid neutralisation agent for industrial and metallurgical applications
• Raw feed for cement manufacture
• Agent for agricultural soil amendment
• Construction aggregate
• Road base and fill material
Indonesia and Southeast Asia in general is undertaking significant infrastructure development
and presents an adjacent local market opportunity for construction materials. Regional markets
in South, Southeast and North Asia provide additional export potential for acid neutralisation and
cement raw material products.
Next Steps
• Progress technical and economic evaluation of development opportunities at Werumata,
incorporating the updated Mineral Resource.
• Advance discussions with prospective customers regarding product specifications, potential offtake
arrangements and commercial applications.
• Continue engagement with the Timor-Leste Government regarding port access, infrastructure and
potential export logistics.
• Undertake further community engagement and assess opportunities for additional drilling to test
extensions and higher-quality limestone horizons.
JORC Code Compliance
This announcement has been prepared in compliance with the 2012 Edition of the JORC Code and the
ASX Listing Rules. The JORC Code Table 1 checklist supporting this resource is included in the
independent technical report prepared by ASEAMCO Pty Ltd (Project 26244, October 2026), which has
been annexed in this ASX announcement. All material assumptions underpinning the resource estimate
are disclosed in this announcement.
This announcement has been approved for release to ASX by the Board of Estrella Resources Limited.
-ENDS-
About Estrella Resources Ltd
Estrella Resources Ltd has exploration projects and mineral rights in Western Australia but is currently
focussing its efforts on the exploration of its Timor Leste portfolio of tenements (known in Timor Leste
as “Concessions”).
Figure 4: Estrella concessions, Timor Leste, with developing prospects.
To-date, Estrella has discovered manganese mineralisation at several sites, with the Ira Miri deposit
having been excavated to extract a 27,000t bulk sample to be sold as a market appraisal exercise.
Exploration for manganese continues.
In addition, Estrella has identified several occurrences of copper mineralisation and is actively pursuing
the growing copper and gold potential.
FURTHER INFORMATION CONTACT
Robert Mencel
Managing Director
Estrella Resources Limited
+61 8 9481 0389
info@estrellaresources.com.au
Media:
David Tasker
Managing Director
Chapter One Advisors
dtasker@chapteroneadvisors.com.au
+61 433 112 936
Competent Persons Statement – Exploration
The information in this announcement that relates to Sampling Techniques, Data and the Reporting of
Exploration Results is based on information compiled by Mr Peter Spitalny, a full-time employee of Estrella
Resources Ltd. Mr Spitalny is a Fellow of The Australasian Institute of Mining and Metallurgy and has sufficient
experience relevant to the style of mineralisation and type of deposit under consideration to qualify as a
Competent Person as defined in the 2012 Edition of the JORC Code.
Competent Persons Statement – Mineral Resource Estimates
The information in this announcement that relates to the Estimation and Reporting of Mineral Resources is
based on information compiled by Mr Robert de Jongh BE Mining (Hons) FAusIMM, Managing Director of
ASEAMCO Pty Ltd. Mr de Jongh is a Fellow of The Australasian Institute of Mining and Metallurgy and has
sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration to
qualify as a Competent Person as defined in the 2012 Edition of the JORC Code.
Compliance Statement
Both Mr Spitalny and Mr de Jongh consent to the inclusion of the matters based on their information in the form
and context in which it appears in this announcement. The Company confirms that it is not aware of any new
information or data that materially affects the information included in this announcement.
Forward Looking Statements
This document may include forward-looking statements. Forward-looking statements include, but are not limited
to, statements concerning Estrella Resources Limited’s planned exploration program and other statements that
are not historical facts. When used in this document, the words such as "could," "plan," "expect," "intend," "may”,
"potential," "should," and similar expressions are forward-looking statements. Although Estrella believes that its
expectations reflected in these forward-looking statements are reasonable, such statements involve risks and
uncertainties and no assurance can be given that further exploration will result in the estimation of a Mineral
Resource.
Werumata Limestone Project
UPDATED STATEMENT of
LIMESTONE RESOURCES
as at 15 October 2026
October 2026 Project 26244
AUSTRALIAN & SOUTH EAST ASIAN MINING CONSULTANTS
Werumata Limestone Project
Updated Statement of Limestone Resources
Project No: 26244
i
Executive Summary
ASEAMCO Pty Ltd (ASEAMCO) was commissioned by Estrella Resources Limited
(Estrella) to prepare an updated statement of the open cut limestone resources
contained within the Werumata Limestone Deposit Exploration and Evaluation
Concession MEL2024-DA-ZA003 (The Concession) in accordance with the 2012
Edition of the JORC Code.
The primary purpose of this updated report is to integrate a substantial new dry bulk
density dataset collected across the deposit's primary geological domains. In the
maiden resource statement, a lack of density data (restricted to approximately 2% of
the total drill core length) constrained the confidence levels, requiring the entire
resource to be classified as Inferred. The acquisition of this comprehensive new
physical data has resolved this constraint, altering the underlying tonnage factors and
allowing the reclassification of parts of two primary horizons from Inferred to the
Indicated Resource category.
The Competent Person for Resource Estimation, Robert de Jongh, relies on his initial
site visit conducted between 23rd and 25th November 2025 during which the following
items were observed:
o Location and infrastructure
o Geological setting
o Drilling progress
o Drillhole logging and sampling methods
Location, Land Tenure and Licensing
The Concession lies on the western border of the Lautém Municipality across sucos
Euquisi, Ililai, Saelari, Samalari and Nunira and has a total area of 4990 hectares. It is
located 170km ENE from the capital city of Dili and is accessed by sealed all-weather
roads.
The Concession was awarded for 4 years on 14th May 2025 to Estrella Resources Ltd
Representação Permanente (ESR-RP) having 100% ownership. ESR-RP is
registered in Timor-Leste and is a wholly-owned subsidiary of Estrella Resources
Limited.
Geology
The targeted mineralisation lies within the Baucau Limestone Formation and the
underlying Batu Putih Chalk. The Baucau Limestone is well exposed near the coastline
and was formed between the Pleistocene Age and the present time in a shallow marine
environment. It is comprised of coralline reef facies, palaeo shoals and beaches, along
with grainstones and rudstones. The average modelled thickness of the Baucau
Limestone in the area tested by drilling is approximately 30m.
The Batu Putih Chalk was formed in a deep marine setting in the Pliocene epoch and
was deposited upon an undulating surface caused by erosion of the underlying older
Cretaceous period sedimentary rocks. The average modelled thickness of the Batu
Putih Chalk in the area tested by drilling is approximately 26m.
Werumata Limestone Project
Updated Statement of Limestone Resources
Project No: 26244
ii
Variably calcareous marl beds are associated with both the Baucau Limestone and
Batu Putih Chalk. The limestone, chalk and marl beds are sub-horizontal and broadly
tabular, as expected in sediments deposited in marine settings.
Defined Horizons and Limestone Quality
The drillhole intersections were classified into seven horizons based on lithology and
assay results. In stratigraphic order these horizons were BCUH, BCUL, LCL, BPUH,
BPUX, BPUL and CL.
It was advised that three products were proposed to be mined and sold from this
deposit:
Product 1: A high-quality product to be sold for the purposes of acid neutralisation;
Product 2: A lower quality product designated for other industrial uses such as the
manufacture of Autoclaved Aerated Concrete (AAC) blocks; mixing with
lime to produce high quality masonry mortar; or as a blending component
for the manufacture of Portland cement, and;
Product 3: A product, which due to its high silica content, is ideal for road paving,
construction aggregate, road base and rock fill.
Due to the cost of mining and value of these products the only economically feasible
extraction technique is the open cut mining method.
Because the sulphur content of the limestone is extremely low it can be concluded that
the calcium and magnesium contents of the limestone overwhelmingly exist as calcium
carbonate and magnesium carbonate. On a scale in which pure calcium carbonate
has an acid neutralising capacity of 100, magnesium carbonate has an acid
neutralising capacity of at least 110. For Product 1 the acid neutralisation capacity
was calculated using the assay values for Calcium and Magnesium Oxide assuming
that all calcium and magnesium exist as carbonates.
Costs and revenues were provided by Estrella. These were considered to be
reasonable. A brief financial analysis was undertaken which determined that the cut-
off grade for acid neutralisation capacity (ANC) for Product 1 was approximately 47%,
while for Product 2 the cut-off grade for ANC was set at 20% which resulted in an
average calcium carbonate content of 30.4% for this product. Product 3 was
designated as any material with ANC less than 20%.
Resources
A geostatistical analysis of horizon thickness was attempted on each of the seven
identified horizons. This analysis was successful for the BCUH, BCUL, BPUH and CL
horizons. Other methods were used for the remaining horizons. The modelling
techniques used for each horizon are presented in Table A.
Werumata Limestone Project
Updated Statement of Limestone Resources
Project No: 26244
iii
Table A – Modelling techniques used for horizon thickness
Horizon Modelling Technique Used
BCUH Geostatistics / Point Kriging
BCUL Geostatistics / Point Kriging
LCL Inverse Distance
BPUH Geostatistics / Point Kriging
BPUX General Purpose Gridding
BPUL General Purpose Gridding
CL Geostatistics / Point Kriging
The success of the geostatistical analysis for the BCUH, BCUL, BPUH, and CL
horizons and would ordinarily have permitted the classification of those resources into
Measured, Indicated, and Inferred categories; however, in the previous estimate, the
lack of density data (restricted to approximately 2% of the total drill core length) meant
the density data was insufficient to support anything but Inferred Resources.
Following the subsequent acquisition and integration of a substantial, domain-specific
bulk density dataset across the deposit, sufficient technical confidence has been
established to upgrade parts of these geostatistically modelled domains to the
Indicated Resource category. The classification boundaries were defined based on
the localized spatial density and frequency of the new physical core measurements.
Portions of these horizons with wider data spacing, along with all remaining horizons
modelled using other techniques, continue to be classified as Inferred.
The overall coefficient of variation within the previous density dataset was 10.4%,
which introduced a material variance range to the resource tonnages and restricted
the deposit to an Inferred status. This also meant that, assuming a normal distribution
for the density values, the likely range of values for the resources is the mean plus or
minus 10.4% of the mean. Now the integration of the comprehensive new density
dataset has allowed the calculation of domain-specific coefficients of variation (CV),
replacing the historical single global metric. For the horizons where geostatistics was
successful and reliable density data was established (BCUH and BPUH), the CV has
been significantly reduced. Assuming a normal distribution, this results in a much
tighter, higher-confidence tonnage range for these upgraded domains. The CV for the
remaining horizons has also been updated to reflect the expanded dataset,
establishing localized variance profiles across the entire deposit.
Every exploration hole contained voids, and these features continue to be factored into
the resource estimates. Across the deposit, the global void percentage was
determined to be 2.8%. This value was rounded and applied as a 97% mining recovery
factor. The updated block model tonnages were multiplied by 97% to obtain the
reported resources.
A summary of the updated resources, alongside their respective classification
categories, is presented in Table B.
Werumata Limestone Project
Updated Statement of Limestone Resources
Project No: 26244
iv
Table B – Summary of Resources
JORC
Classification
Product 1
ANC ≥47%
(Mt)
Product 2
ANC 20%–47%
(Mt)
Product 3
ANC <20%
(Mt)
Total Limestone
Resource
(Mt)
LOWER ESTIMATE
• Indicated 250 — — 250
• Inferred 110 31 91 232
Lower Total 360 31 91 482
CENTRAL ESTIMATE
• Indicated 274 — — 274
• Inferred 117 33 109 259
Central Total
(MRE Baseline)
391 33 109 533
UPPER ESTIMATE
• Indicated 299 — — 299
• Inferred 124 35 127 286
Upper Total 423 35 127 585
Note that the values in Table B may not add up due to rounding.
As a result of the successful collection of reliable density data for horizons BCUH and
BPUH, approximately 51% of the total resource has now been classified as Indicated
Resources. The Indicated Resources also represent 70% of the premium Product 1.
The relatively low economic value for Product 3 may result in a decision not to mine
the CL horizon located at the base of the stratigraphic sequence. Excluding this
horizon from the resources would result in a reduction of the Central Estimate of the
resources from 533 million tonnes to 430 million tonnes, leaving only 5.5 to 6.8 million
tonnes of Product 3 material to be mined in association with the extraction of Products
1 and 2.
Werumata Limestone Project
Updated Statement of Limestone Resources
Project No: 26244
v
TABLE OF CONTENTS
1 INTRODUCTION.......................................................................................................................................7
2 METHODOLOGY.......................................................................................................................................8
2.1 PROCEDURE ........................................................................................................................................................8
2.2 DATA AND REFERENCES...................................................................................................................................8
3 PROJECT DESCRIPTION ........................................................................................................................9
3.1 LOCATION AND ACCESS.....................................................................................................................................9
3.1.1 Limestone Use................................................................................................................................................................9
3.2 HISTORY, LICENSING AND LAND TENURE..................................................................................................10
4 GEOLOGY................................................................................................................................................. 11
4.1 REGIONAL GEOLOGY.......................................................................................................................................11
4.2 LOCAL GEOLOGY .............................................................................................................................................11
4.2.1 Stratigraphy................................................................................................................................................................11
4.2.2 Drilling, Sampling and Logging Techniques...................................................................................................14
4.2.3 Sample Transfer and Laboratory Testing .......................................................................................................15
4.2.4 Correlation and Structural Interpretation......................................................................................................15
4.2.5 Assay Results ...............................................................................................................................................................16
5 MODELLING ........................................................................................................................................... 18
5.1 STRUCTURAL MODELLING.............................................................................................................................18
5.1.1 Structure Floor Modelling......................................................................................................................................18
5.1.2 Structure Thickness Modelling.............................................................................................................................18
5.1.3 Modelling of Assays...................................................................................................................................................19
5.1.4 Density Data................................................................................................................................................................20
6 RESOURCES............................................................................................................................................ 24
6.1 PRODUCTS........................................................................................................................................................24
6.2 AREAL EXTENTS..............................................................................................................................................24
6.3 THICKNESS CONSTRAINTS.............................................................................................................................24
6.4 RESOURCE RECOVERY....................................................................................................................................24
6.5 RESOURCE POLYGONS....................................................................................................................................24
6.5.1 Resource Polygons and Classification Boundaries.......................................................................................24
6.6 RESOURCE ESTIMATES...................................................................................................................................36
7 STATEMENT OF COMPETENCE........................................................................................................ 38
8 JORC CODE – TABLE 1 – WERUMATA PROJECT......................................................................... 39
The supporting documentation is included in the following appendices as separate files:
APPENDIX A – DRILLHOLE SURVEY DATA
APPENDIX B – DRILLHOLE HORIZON INTERCEPTS
APPENDIX C – REVERSE CIRCULATION DRILLHOLE LIMESTONE ASSAYS
APPENDIX D – REVERSE CIRCULATION LTHOLOGY LOGS
APPENDIX E – DIAMOND DRILLHOLE LTHOLOGY LOGS
APPENDIX F – DIAMOND DRILLHOLE DENSITY RESULTS - CORE SAMPLING
APPENDIX G – DIAMOND DRILLHOLE DENSITY RESULTS – CORE TRAY WEIGHING
Werumata Limestone Project
Updated Statement of Limestone Resources
Project No: 26244
vi
List of Tables
TABLE 4.1 – MODELLED HORIZONS .......................................................................................... 12
TABLE 4.2 – SUMMARY OF SIGNIFICANT ASSAY RESULTS ........................................................ 17
TABLE 5.1 – STRUCTURAL FLOOR MODELLING PARAMETERS .................................................. 18
TABLE 5.2 – MODELLING TECHNIQUES USED FOR HORIZON THICKNESS .................................... 18
TABLE 5.3 – SEMI-VARIOGRAM PARAMETERS FOR THICKNESS ................................................ 19
TABLE 5.4 – SEMI-VARIOGRAM PARAMETERS FOR ACID NEUTRALISATION CAPACITY ............ 19
TABLE 5.5 – ACID NEUTRALISATION CAPACITY MODELLING PARAMETERS............................. 20
TABLE 5.6 – HISTORICAL LABORATORY DENSITY DATA STATISTICS (MAIDEN MODEL).......... 21
TABLE 5.7 – HISTORICAL DENSITY ESTIMATES FOR EACH MODELLED HORIZON...................... 22
TABLE 5.8 – UPDATED DOMAIN DENSITY STATISTICS, RANGES, AND JORC IMPACT............... 23
TABLE 6.1 – MODELLING TECHNIQUES AND RESOURCE POLYGON CONSTRAINTS .................... 25
TABLE 6.2 – SUMMARY OF RESOURCES BY HORIZON & PRODUCT............................................ 36
TABLE 6.3 – PERCENTAGE OF RESOURCES BY ELEVATION, HORIZON & CLASS ..................
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