SUNSTONE METALS LTD — AGM Information 2025

Oct 23, 2025

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Defining Multi Decade Gold-Copper Projects

Mr Patrick Duffy, MD & CEO Annual General Meeting Presentation 24 October 2025

sunstonemetals.com.au

ASX: STM

Disclaimer

DISCLAIMER

To the maximum extent permitted by law, no representation, warranty or undertaking, express or implied, is made and, to the maximum extent permitted by law, no responsibility or liability is accepted by Sunstone or any of its officers, employees, agents or consultants or any other person as to the adequacy, accuracy, completeness or reasonableness of this Presentation. To the maximum extent permitted by law, no responsibility for any errors or omissions from this Presentation whether arising out of negligence or otherwise is accepted.

This Presentation contains general information about Sunstone Metals Limited (Sunstone) which is in the business of exploring for minerals which is a speculative and risky venture. It does not purport to contain all the information that a prospective investor may require. The Presentation should not be considered as an offer or invitation to subscribe for or purchase of any securities in Sunstone and no agreement to subscribe for securities will be entered into on the basis of this Presentation. Potential investors should conduct their own investigation and analysis and should check the accuracy, reliability, and completeness of the information provided and obtain independent and specific advice from appropriate professional advisors.

FORWARD-LOOKING STATEMENTS

This Presentation includes certain statements that may be deemed “forward-looking statements”. All statements in this Presentation, other than statements of historical facts, that address future activities and events or developments that Sunstone expects, are forward looking statements.

Although Sunstone believes the expectations expressed in such forwardlooking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or

developments may differ materially from those in the forward-looking statements. Factors that could cause actual results to differ materially from those in forward-looking statements include market prices, continued availability of capital and financing, and general economic, market or business conditions.

Investors are cautioned that any such statements are not guarantees of future performance and that actual results or developments may differ materially from those projected in forward-looking statements.

EXPLORATION TARGETS

This presentation contains information on Exploration Targets. The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Resource for the exploration target area reported. It is uncertain if further exploration will result in the estimation of a Resource.

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Our Strategy Crafting our advantage

We have the necessary skillsets to execute Tier 1 projects

We own large, long-life, low-AISC assets

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High Quality
Gold-Copper
Assets
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In the Right
Commodities
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Resource growth, scalable development, funding pathways

Copper Gold 25% 75%

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Our Flagship Assets

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El Palmar

Deliverin a centur -scale asset g y

• Major bulk scale, low-cost gold-copper deposit in Northern Ecuador

• 17,799m of drilling defines orebody extending over 1,750m deep

• 1.2Moz AuEq[2 ] Maiden JORC Resource[1] from top 450m of the T1 target

• 15M – 45Moz AuEq[3 ] Exploration Target[1 ] across T1, T2 & T3 targets

Bramaderos

Large-tonnage, low-cost, ideal location

• High grade gold-copper-silver systems extending from surface

• World class thickness and grades incl. 185m @ 2.85g/t AuEq

• 2.7Moz AuEq[4 ] Maiden JORC Resource[6 ]

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100km
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  - **4.2M – 10.3Moz AuEq[5 ] Exploration Target[6 ]** (Brama-Alba and Limon)

• 1 See ASX announcement 22 Oct 2024 2 64Mt at 0.60g/t AuEq for 1.2Moz AuEq

• 3 1.0 -1.2Bt at grade between 0.3-0.7 g/t Au and 0.1-0.3% Cu 4 156Mt at 0.53g/t AuEq for 2.7Moz AuEq

• ASX:STM

5 Brama Alba: 225-360Mt at grade between 0.25-0.54 g/t Au and 0.1-0.12% Cu Limon: 30-40Mt at grade between 0.8-1.1 g/t Au and 12-15.8g/t Ag

6 See ASX announcement 13 December 2022 Refer slides 22 to 25 for full JORC details

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Our Experienced Team

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BOARD OF DIRECTORS

MANAGEMENT TEAM

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Patrick Duffy

Dr Bruce Rohrlach

Managing Director & CEO

General Manager - Exploration

Ex-WMC, Intrepid and SolGold, Dr Rohrlach has been part of several major porphyry discoveries and oversees all exploration programs at Sunstone

Ex-Red 5, Glencore and Xstrata, Mr Duffy brings international leadership and capital markets experience with a successful mine development track record

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Malcolm Norris

Lucas Welsh

Non-Executive Chair

CFO & Company Secretary

Ex-WMC, Intrepid and SolGold, Mr Norris has been part of several major global porphyry discoveries and brings mineral exploration and management expertise

Former CFO of St Barbara, Mr Welsh is a specialist resources financial executive with international mining, capital markets and governance expertise

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Neal O’Connor

Ray Robinson

Non-Executive Director

GM – Studies & Tech Services

Former Xstrata Copper Chief Legal Counsel, Mr O’Connor has extensive experience developing South American mining operations and infrastructure

Ex-PanAust, Placer Dome and Intrepid, Mr Robinson has extensive mining studies and operations experience, and oversees all study programs at Sunstone​

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Stephen Stroud

Rodrigo Izurieta

Non-Executive Director

Country Manager

Mr Stroud is Director – Corporate Finance at Morgans and brings extensive capital markets knowledge and investor relationships

Based in Quito, Ecuador, and US-educated, Mr Izurieta is highly respected with deep relationships in the local mining industry and government

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Ecuador – Rich in Gold and Copper

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100km
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Apr-25 President Noboa re-elected for a four-year term • President actively encouraging responsible mining • Single national mining department

Forms part of the worlds most endowed copper gold belt

• 2 world-class operating mines – Fruta del Norte, Mirador

• All majors present (BHP, Newmont, Barrick, Codelco)

• Recent Mining Investments

• Adventus – El Domo Curipamba Copper/Gold Project

• Solaris – Warintza Copper Project

• Lumina Gold – Cangrejos Gold Project

2024/25 Transaction Highlights

• Solgold US$750m financing for Cascabel Project

• Hancock US$120m 49% JV earn-in with ENAMI

• CMOC C$581m acquisition of Lumina Gold in April 2025

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Ecuador – Our Cost Advantage

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Ecuador has two world-class, lowest cost-quartile operating mines

• Fruta del Norte Gold Mine (Lundin Gold)

• Mirador Copper Mine (Chinese-owned)

Low mining input costs are a competitive advantage

• Energy and Labour both significantly lower than Australia and Canada

• Potential for Sunstone’s projects to be in the lowest cost quartile

• Complimented by very low stripping ratios

Hydro provides base energy load for the country (>90%)

• Potential for low-cost, low-carbon emission mining

Ecuador’s currency is USD

• Provides protection against inflation

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Comparable energy prices (Dec 2023) [1]
$0.25 $1.50
$1.17
$0.20 $1.06 $1.01 $1.20
$0.15 $0.90
$0.47
$0.10 $0.60
$0.05 $0.30
$0.09 $0.14 $0.12 $0.19
$- $-
Ecuador Chile Canada Australia
Electricity Diesel
Comparable mining labour costs (Dec 2023) [2]
$120
$100
$80
$60
$106
$88
$40
$72 $74
$20 $43 $40
$30
$17
$-
Ecuador Chile Canada Australia
Entry-Level Mining 3-Yr Mining Professional 100km
US$/kWh US$/litre
US$k's
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Source:

1. https://www.globalpetrolprices.com/

2. https://www.erieri.com/salary/job/mining-engineer, https://ca.talent.com/salary?job=Mining

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Our Commodity Advantage

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Record high AUD gold prices – up >60% in 2025

• Regional conflicts, trade restrictions, shift from USD

• Inflation subsiding, USD rate cuts are imminent  Favorable AUD:USD exchange rate lifts value to Sunstone

Strategic demand for tier-1 scale copper assets

• New copper supply coming from difficult jurisdictions

• Net Zero Transition requires huge increase in copper  Increasing M&A from multinational miners for large projects

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5-year USD Gold Price
4,500
Gold price
US$4,209/oz
15-Oct-25
3,500
2,500
1,500
500
$/oz
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Copper Demand and Supply imbalance likely to grow
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Source: Bloomberg

Source: Sprott Webcast, March 23

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Bramaderos & Limon

Open pit and high-grade multi-decade development opportunities Located in an ideal mining location

sunstonemetals.com.au

ASX: STM 9 99

ASX:STM

Bramaderos: The Ideal Project

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Bramaderos Project, Au-Equivalents (Moz’s)
14
2
12 0.9 - 1.7
Potential to deliver MRE
10 growth by converting a
portion of the
8 Exploration Target
through further drilling 3.3 - 8.6 3
6
4
2
1
Brama Alba, 2.7
0
Mineral Resource Exploration target
New discoveryNew discovery [2][4] : :
113m @ 0.64g/t AuEq 113m @ 0.64g/t AuEq
Porphyry Limon
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Background image is gold-in-soils

1 156Mt at 0.53g/t AuEq for 2.7Moz AuEq.

2 30-44Mt at grade between 0.9-1.2g/t Au Eq for 0.8-1.7oz AuEq

3 255-360Mt at grade between 0.40-0.74 g/t AuEq for 3.3-8.6Moz AuEq

4 See slides 22 - 25 for full JORC details.

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Bramaderos: Our Two Areas of Focus

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Brama-
Alba
Limon; just behind hill
Limon
Area of gold-silver
1.7 km
mineralisation
1.0 km
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Brama-Alba: 1.6km long mineralised porphyry system

• Outcropping gold-copper-silver

• MRE undertaken by Tier 1 consultants CSA

• Attractive mining metrics

• Very low strip ratio

• Higher grade domains close to surface

• Significant upside to grow the porphyry resource and define higher grades

Limon: 1.7km x 1.0km epithermal gold-silver system

• High grade intersections including 185m @ 2.85g/t AuEq

• Potential for a deeper large gold-copper-silver porphyry

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Bramaderos: Unlocking Regional-Scale

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High-tonnage, near-surface Mineral Resource at Brama-Alba with depth extensions and nearby targets ready for drilling

• The Bramaderos cluster of gold-copper mineralised

• bodies at surface now covers an area of 2km x 1.8km Hills in background

• Potential for a very large, multi-decade, low-cost open

• pit operation

• Recent surface trench results from new Copete gold:

• copper porphyry discovery (outside Exploration Target)[1]

• 113m @0.64/gt AuEq within 214m @0.50g/t Au-Eq

Sunstone is currently updating the Brama-Alba Mineral Resource estimate that will form the basis for a Project Scoping Study in 2026

1 See ASX announcement 12 November 2024

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Limon: A High-Grade Discovery

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Hills in background
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1: ~17k m’s of drilling to-date (12k m’s in the Limon epithermal)

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Bramaderos: Development Optionality

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Bramaderos is a world-class gold and copper discovery with multiple pathways to establishing a large 10M+oz AuEq mining centre in southern Ecuador

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Limon to provide the
Stage 1:
revenue and balance sheet
Establish Limon
to fund larger gold-copper
epithermal as a higher-
porphyry development
grade gold-silver mine
Lower capital cost
development
Stage 3:
Convert porphyry targets
Stage 2:
Grow Brama-Alba, at Playas, Porotillo, Limon
Future exploration growth
Melonal and Copete
opportunity
porphyries from
surface
Open Pits to feed large-
tonnage milling operation
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El Palmar

Defining a bulk-scale, low-cost Gold-Copper Tier 1 deposit

sunstonemetals.com.au

ASX: STM 15 1515

ASX:STM

El Palmar: Surrounded by Giants

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Highly prospective mineralised district related to the Toachi Fault Zone

Tier 1 regional deposits

• 2.7Bt Alpala copper-gold porphyry deposit (0.53% CuEq) at Cascabel

• 0.53Bt Tandayama-America copper-gold porphyry deposit

• (0.36% CuEq) at Cascabel

• 1Bt Llurimagua copper-moly porphyry deposit (1.0% CuEq)

Hancock investing US$120m to earn 49% into JV with state-owned ENAMI in northern Ecuador (adjacent to El Palmar)

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El Palmar: Uncovering the next Giant

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Significant gold-copper deposit with mineralisation extending beyond 1,750m deep

• Drilling totaling 17,699m completed to date

• Three targets defined, with T2 and T3 both extending at depth beyond 1,750m

• Deep drilling at T3 delivers results such as 251m @ 0.56g/t AuEq confirming consistent grade at depth

• Maiden resource defined from near-surface drilling

Gold and copper Exploration Target of 15M - 45Moz AuEq[1]

• 1.0Bt to 1.2Bt at a grade between 0.3g/t to 0.7g/t gold and 0.1% to 0.3% copper

• Contained metal of between 10Moz and 27Moz gold and 1.0Mt to 3.7Mt copper

• Immense potential for El Palmar to grow:

• Based on only three of five identified targets

• Potential for copper content to increase

1 See slides 22 - 25 for full JORC details

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El Palmar: True Tier-1 Scale

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El Palmar strategic advantage to commence as an Open Pit

• Same scale cross-section

• comparison with the 3Bt Alpala deposit at Cascabel

• Depth to top of the main Alpala orebody is ~700m

Immense potential for El Palmar to continue to grow

• High tonnage, low-cost potential

• 1. Bulk mining / processing at scale
• 1. Low strip ratio

• Lower labour and energy costs in the host jurisdiction

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Significant room for value appreciation

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ASX STM Shares on Issue 6,341M Market Capitalisation A$133.3M[1] Cash and Equities A$2.7M[2] Enterprise value A$130.6M Outstanding options (in-the-money) 284M[4]

Share ownership

1 based on the share price of $0.021 at 20 Oct 2025 2 Cash at 30 June 2025

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Institutional &
Family Office
41%
Other 54%
Board &
Management 5%
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3 Source: Company Public MROR Statements and announcements. Refer to page 26 for further details.

4 As at 17 October 2025. $1.8M of options have been exercised since 1 July 2025.

Strategic options being pursued to unlock latent value:

1. JV asset partnership(s)

2. Strategic investment (in Sunstone)

3. Corporate opportunities

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CALL EMAIL WEB ASX:STM
+61 3 7044 2627 info@sunstonemetals.com.au sunstonemetals.com.au
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Our Community Focus

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Sunstone appreciates the strong community support that it has at its projects and takes its environmental, social and governance issues very seriously.

Inaugural Sunstone Sustainability Report released 27 November 2023

Significant environmental monitoring programs across all projects

Involved in various high-impact community programs at Bramaderos and El Palmar

Undertakes considerable training programs across a large range of skills for workers and the communities in which we operate

Sunstone works with the local communities to assist where possible, for example, during the pandemic Employment and skills development for local communities

Drilling is fully permitted and environmentally compliant at Bramaderos and El Palmar

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Resource and Overview

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Sunstone has an advanced portfolio of exploration projects in Ecuador. The portfolio comprises:

1. The Bramaderos Gold-Copper Project

Sunstone owns an 87.5% interest, and SolGold Canada, Inc. (formerly Cornerstone Capital Resources) a subsidiary of SolGold, holding 12.5% (loan carried through to start of commercial production). The Bramaderos gold-copper project is located in Loja province, southern Ecuador, and is highly prospective for the discovery of large porphyry gold-copper systems, and high-grade epithermal gold systems. The Bramaderos concession is host to multiple fertile mineralised systems with significant discovery potential.

The Brama-Alba porphyry gold-copper-silver deposit, within the Bramaderos concession contains an initial Mineral Resource estimate of 156Mt at 0.53g/t AuEq for 2.7Moz gold-equivalent. In addition to this is the Bramaderos project porphyry gold-copper-silver Exploration Target of between 3.3Moz and 8.6Moz AuEq within 255 to 360Mt at a grade between 0.40 and 0.74g/t AuEq* (see ASX release dated 13 December 2022). The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource for the target area reported. It is uncertain if further exploration will result in the estimation of a Mineral Resource.

An Exploration Target for the Limon epithermal gold-silver deposit was released on 9 November 2023 (also refer to ASX release dated 5 February 2024) consisting of between approximately 30 and 44 million tonnes at a grade of between 0.9 and 1.2g/t AuEq, for between 0.9 and 1.7mill oz AuEq. The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource for the target area reported. It is uncertain if further exploration will result in the estimation of a Mineral Resource.

The company confirms that it is not aware of any new information or data that materially affects the information included in the original market announcement for the Mineral Resource estimate and Exploration Target referred to above and, that all material assumptions and technical parameters underpinning the estimates continue to apply and have not materially changed. The company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcement.

• The gold equivalent calculation formula for porphyry gold-copper-silver mineralisation is AuEq(g/t) = (Au grade x Au price x Au recov / 31.1035) + (Ag grade x Ag price x Ag recov / 31.1035) + (Cu grade x Cu price x Cu recov / 100)) / (Au price x Au recov / 31.1035). The prices used were US$1,800/oz gold and US$9,500/t copper and US$22/oz silver. Recoveries are estimated at 89% for gold, 85% for copper, and 60% for silver based on metallurgical studies (see ASX release dated 13 December 2022)

• The gold equivalent calculation formula for epithermal gold-silver mineralisation is AuEq(g/t) = Au(ppm) + (Ag (ppm)/82). The prices used were US$1,800/oz gold and US$22/oz silver. Recoveries are estimated at over 90% for gold and 90% for silver from metallurgical studies (see ASX release dated 9 November 2022).

In Sunstone’s opinion all the elements included in the metal equivalents calculation have reasonable potential to be recovered and sold.

JORC Classification	Tonnage (Mt)	Au (g/t)	Cu (%)	Ag (g/t)	AuEq (g/t)	AuEq* (Mozs)
Indicated	9	0.38	0.09	1.1	0.53	0.2
Inferred	147	0.35	0.11	1.3	0.53	2.5
Total	156	0.35	0.11	1.3	0.53	2.7

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Resource and Overview

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Sunstone has an advanced portfolio of exploration projects in Ecuador. The portfolio comprises:

2. The El Palmar Gold-Copper Project

Sunstone holds 74.5% of the highly prospective 800ha El Palmar gold-copper porphyry project in Ecuador. Sunstone can acquire 100% through a Staged Acquisition Agreement. A Staged Acquisition Agreement to acquire the nearby Verde Chico Project has also been signed. The El Palmar and Verde Chico gold-copper projects are located in Imbabura province, northern Ecuador, within the same geological belt that includes the giant Alpala, Tandayama-America and Llurimagua porphyry copper-gold and copper-molybdenum deposits.

The El Palmar porphyry gold-copper-silver deposit within the El Palmar concession contains an initial Mineral Resource estimate of 64Mt at 0.60g/t AuEq for 1.2Moz AuEq. In addition to this is the El Palmar Exploration Target of between 15Moz and 45Moz AuEq within 1.0Bt to 1.2Bt at a grade between 0.3g/t to 0.7g/t gold and 0.1% to 0.3% copper for contained metal of between 10Moz and 27Moz gold and 1.0 to 3.7Mt copper (see ASX release dated 22 October 2024). The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource for the target area reported. It is uncertain if further exploration will result in the estimation of a Mineral Resource.

• The gold equivalent calculation formula is AuEq (g/t) = ((Au grade x Au price x Au recov / 31.1035) + (Ag grade x Ag price x Ag recov / 31.1035) + (Cu grade x Cu price x Cu recov / 100)) / (Au price x Au recov / 31.1035). The prices applied were US$1,800/oz gold, US$4.50/lb copper and US$22/oz silver. Recoveries are estimated at 90% for gold, 78% for copper (excluded for oxide material), and 60% for silver based on metallurgical studies. In Sunstone’s opinion all the elements included in the metal equivalents calculation have reasonable potential to be recovered and sold.

JORC Classification	Tonnage Mt	Average Grade	Average Grade	Average Grade	Average Grade	Average Grade	Material Content	Material Content	Material Content	Material Content
		AuEq (g/t)	Au (g/t)	Ag (g/t)	Cu (ppm)	Cu (%)	AuEq (Koz)	Au (Koz)	Ag (Koz)	Cu (Kt)
Indicated	5	0.63	0.42	0.81	1,456	0.15	100	100	100	7
Inferred	59	0.59	0.40	0.65	1,290	0.13	1,100	700	1,200	70
TOTAL	64	0.60	0.41	0.66	1,301	0.13	1,200	800	1,300	80

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Competent Person Statement

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Competent Persons Statement - Bramaderos

The information in this report that relates to Mineral Resources is based on information compiled by Mr Aaron Meakin. Mr Aaron Meakin is a full-time employee of CSA Global Pty Ltd and is a Member and Chartered Professional of the Australasian Institute of Mining and Metallurgy. Mr Aaron Meakin has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the Australasian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code). Mr Aaron Meakin consents to the disclosure of the information in this report in the form and context in which it appears.

Competent Persons Statement – El Palmar

The information in this report that relates to Mineral Resources is based on information compiled by Mr Rob Spiers. Mr Rob Spiers is a full-time employee of Spiers Geological Consultants (SGC) and is a Member of the Australasian Institute of Geoscientists (AIG). Mr Rob Spiers has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the Australasian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code). Mr Rob Spiers consents to the disclosure of the information in this report in the form and context in which it appears.

Exploration Target Competent Person – Bramaderos and El Palmar

The information in this report that relates to exploration results and exploration targets and results is based upon information reviewed by Dr. Bruce Rohrlach who is a member of the Australasian Institute of Mining and Metallurgy. Dr. Rohrlach is a full-time employee of Sunstone Metals Ltd and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves”. Dr. Rohrlach consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.

See ASX announcements

• 22 October 2024 – El Palmar MRE and Exploration Target

• 21 August 2024 - More Limon high grade gold and silver in drilling

• 6 August 2024 - High-grade results expand size of Limon

• 17 July 2024 - El Palmar trenching enhances significant Resource potential

• 6 June 2024 - Limon drilling to start in known high-grade areas Limon

• 22 May 2024 - Visible gold in trenches

• 15 May 2024 - El Palmar significant gold-copper mineralisation at surface

• 18 April 2024 - Limon large mineralised system, multiple high-grade clusters 5 February 2024 – Limon Exploration Target – Additional JORC Information 31 January 2024 - Limon gold-silver discovery grows

• 19 December 2023 – Limon gold-silver discovery grows significantly

• 27 November 2023 – Sustainability Report released

• 23 November 2023 – El Palmar gold target, Verde Chico work commencing

ASX announcements (continued)

• 9 November 2023 – Large Limon Exploration Target

• 18 October 2023 – Limon – Bumper results, greatly expands scale

• 12 October 2023 – Limon drilling growing scale

• 18 September 2023 – High grade, near surface gold at Limon

• 11 September 2023 - El Palmar 2nd hole confirms T3 strongly mineralised porphyry

• 15 August 2023 - Limon gold discovery continues to grow

• 3 July 2023 – High grade gold and silver at Limon, Bramaderos

• 20 June 2023 – El Palmar T3 gold-copper porphyry discovery

• 28 April 2023 – El Palmar drilling intersects porphyry copper system

• 14 April 2023 – Limon emerging as major discovery with visible gold in hole

• 29 March 2023 – Limon epithermal drilling results

• 18 January 2023 – Limon delivers porphyry discovery

13 December 2022 – Bramaderos MRE and Exploration Target

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Information on Exploration Target

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Bramaderos

The Bramaderos porphyry Exploration Target within the Bramaderos concession is estimated from 3 areas – the extensions to the Brama-Alba system that are not captured in the Mineral Resource estimate ( MRE ), and mineralisation drilled at the targets of Melonal and Limon porphyry mineralisation.

The Exploration Target does not include known porphyry mineralisation at Sandia, Porotillo, Playas, Copete or Yeso. It was decided to not include these areas because Sunstone has not yet completed any or sufficient drilling in these areas. Some historical drilling has been completed at Porotillo. Further work in these areas will be undertaken and they are expected to contribute to an expanded Exploration Target in future.

Several areas of mineralisation have been identified outside of the area of the MRE. The MRE captured all material within a ‘Mineralisation Wireframe’, and within an economically modelled pit. Some drill holes that intersected mineralisation are outside the mineralisation wireframe, and either within or outside the pit. Inadequate drilling exists in these areas to show continuity. Furthermore, the effect of the reasonable prospects of economic extraction was to exclude 14% of material. This material has been captured in the Exploration Target.

Six domains were identified as having clear potential for additional mineralisation and these were reviewed either on a depth slice basis, or a block basis. Volumes were calculated and grade was assigned based on nearby data and on comparison with the overall Brama-Alba grade.

The Melonal target is a continuation of the Brama-Alba system. It is geologically grouped with Brama-Alba. Recent drilling by Sunstone, and historical drilling from 2007, has confirmed that the Melonal target is mineralised, and that mineralisation is hosted in rocks the same as those drilled at the nearby Brama-Alba deposit. The mineralised rocks are coincident with a discrete sub-vertical magnetic anomaly measuring up to 400m in diameter, and with a vertical extent of over 1,000m. The Exploration Target for Melonal was considered to a depth of 500m. The Melonal target straddles the approved Bramaderos-01 and Bramaderos-02 concessions.

Sunstone has drilled 8 effective diamond holes at the Limon porphyry target. Mineralisation has been intersected in a number of holes. A trench (LM_TR_01) was completed at Limon prior to drilling in an area of outcropping stockwork veining and minor secondary copper mineralisation. It returned 97m at 0.73g/t gold and 0.23% copper. A recent hole drilled under the trench has intersected similar stockwork veined intrusive and contains chalcopyrite.

This area around Trench TR_LM_01 has been included in the porphyry Exploration Target where more drilling is required to allow inclusion in a Mineral Resource estimate.

This target area will be further explored with drilling programs to be executed over the next two years, subject to the Company’s funding ability.

Limon epithermal

The Limon epithermal Exploration Target was estimated on target prospects where there was a combination of diamond drilling (by Sunstone), geological mapping, trenching, geochemistry (soils) and to a lesser extent geophysical data (magnetics) which could support the geological and mineralisation concept model.

areas of somewhat coincident gold, silver, zinc, lead, copper, tellurium and arsenic. Target areas have also been strengthened using alteration mineralogy from a hand-held Terraspec instrument. These data assist in mapping the alteration zones most likely to be associated with epithermal mineralisation.

Drilling at Limon has also intersected a high sulphidation system in holes LMDD004 and 006, which included intersections of 13.3m at 0.43% copper and 0.11g/t gold, within 59.6m at 0.16% copper.

Standard geological mapping and rock chip sampling has also been undertaken across the Limon target area.

The volume ranges for the initial Exploration Target in the Central Shoot were estimated using cross sections and 3-D modelling in Leapfrog software, based upon an analysis of drilling, mineralised rock types, grade distribution, potential for extrapolation of mineralisation continuity and interpreted geological risk.

The volume ranges for the other components were estimated from geological interpretation and guided by extent of surface geochemical anomalism, supplemented by preliminary drilling. A conservative approach was taken to the potential distribution of gold and silver bearing veins.

This target area will be further explored with drilling programs to be executed over the next two years, subject to the Company’s funding ability.

El Palmar

The Exploration Target within the El Palmar concession is estimated from within the T1, T2 and T3 areas.

The Exploration Target does not include interpreted or known porphyry mineralisation at the T4 and T5 target areas. It was decided to not include these areas because Sunstone has not yet completed any drilling at T4 and has conducted only minor drilling at T5. Further work in these areas will be undertaken and they are expected to contribute to an expanded Exploration Target in future.

The components of the exploration target are based on a combination of diamond drilling conducted by Codelco (during 2012) and by Sunstone (during 2022 and 2023), ground magnetics, multi-element soil sampling, multielement rock chip and channel sampling, mulit-element trench sampling and deep magnetic inversion anomalies modelled from ground magnetic data.

Wireframes of the areas within the Exploration Target areas were created in Leapfrog software using data interpreted from the Mineral Resource block model, iso-surface contours of modelled magnetic intensities, and grade ranges in available diamond drill holes. The volumes were multiplied by a specific gravity of 2.72g/cc (the average density of the T1 resource) to determine the tonnage range of the target. Grade ranges were determined with reference to drill intersection and surface rock chip assays.

The next step in testing these targets is primarily diamond drill testing. The targets have been adequately defined, but drill programs still require detailed planning regarding the number of drill holes, their azimuths, dips, and final depths. Drilling of these targets will be undertaken over the next two years, subject to the company's funding availability.

The Limon alteration area has been covered with soil sampling on a 50m x 50m grid. This survey is an important exploration method which identified several gold-in soil anomalies that are primary targets for drilling. The soil geochemical data is further interpreted using related element associations typical of epithermal systems, such as

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Peer Comparison Data (page 19)

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• Share price at close of trading 20 October 2025

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