Numerous High-Grade Assays Extend Tolmer Silver Discovery

Multiple new >2,000g-m Ag assays; metallurgical testwork to begin

ADELAIDE, AU / ACCESS Newswire / August 17, 2026 / HIGHLIGHTS

• Recent 3,677m drilling program targeted infill and extension of high-grade Tolmer silver discovery, after preliminary testwork yielded a high-grade concentrate grading over 100,000 g/t Ag (10% silver)¹

• New high-grade assays infill Tolmer's 'western silver zone' and extend its strike to over 500m, while also adding broad, high-grade intersections to the 'eastern gold zone'. These include:

Barton Gold Holdings Limited (ASX:BGD)(OTC PINK:BGDFF)(FRA:BGD3) (Barton or Company) is pleased to announce further shallow, broad and high-grade assays at its South Australian Tolmer Silver discovery (Tolmer). Tolmer is located at its Tarcoola Gold Project (Tarcoola), where during 2025 Barton announced one of Australia's highest-grade modern silver discoveries with an intersection of 6m @ 4,747 g/t Ag from only 46m depth.¹

These assays have further infilled Tolmer's shallow, high-grade 'western silver zone' mineralisation and extended it to over 500m strike, also yielding broad high-grade intersections in the 'eastern gold zone'. Preliminary analyses for petrology and structural interpretation are now underway. Barton will also expedite full metallurgical analysis of Tolmer mineralisation by preparing composite samples taken from recent drilling.

Commenting on the latest Tolmer drilling results, Barton MD Alexander Scanlon said:

"Our South Australian Tolmer silver discovery continues to yield broad, high-grade silver assays across an expanding footprint. With a shallow profile and having produced trial concentrates grading over 100,000 g/t Ag, Tolmer is already hinting at real potential for a low-cost, high-margin operation. We will share our further analysis in due course.

"We are also planning to update our 3.1 million ounce Tunkillia silver Resource, where 58,000m drilling was recently completed to support JORC upgrades, a Pre-Feasibility study, a Mining Lease application and financing discussions.

"Barton's Tolmer and Tunkillia silver assets are emerging as potentially significant contributors to our South Australian precious metals strategy, whether developed as a complement to our regional gold holdings or on a standalone basis."

New assays extend Tolmer silver discovery

During March 2025, Barton announced one of Australia's highest-grade modern silver discoveries at Tolmer, where two shallow horizons (<50m) host peak silver and gold grades up to 17,600 g/t Ag and 51.2 g/t Au and a ‘western silver zone' sample produced a trial concentrate grading >100,000 g/t Ag (~10% silver).²

New assays from 3,677m reverse circulation (RC) drilling have further infilled the high-grade 'western silver zone' and extended its footprint of shallow silver mineralisation to over 500m total strike length.³ These have also infilled the ‘eastern gold zone' with broad, shallow high-grade gold intersections.

Fig. 1 - Tolmer map with Pb background, Ag contours (white), prior (black) & May-June 2026 drilling (red)³

Key new significant assays received include (note: holes TBM0289 - TBM0291 are located in the 'eastern gold zone'):

Table 1 - New key 'western silver zone' and 'eastern gold zone' assays from May-Jun 2026 drilling

Shallow neighbouring silver- and gold-dominant zones

The 'western silver zone' hosts an ‘upper horizon' of broad, shallow silver mineralisation largely independent of gold, and a second ‘lower horizon' at the boundary of oxide and fresh zones hosting silver and gold in broad intervals with grades up to 17,600 g/t Ag and 51.2 g/t Au.⁴ Mineralised structures extend into fresh rock below. Figure 2 highlights new >4,000g-m assays near discovery hole TBAC0130 (6m @ 4,747 g/t Ag from 46m).⁴

Figure 2 - Tolmer 'silver zone' cross-section A with anomalous Ag-Pb & key intersections

The 'eastern gold zone' hosts gold as the dominant form of mineralisation. Broad, high-grade mineralisation has been intersected to over 200m depth including 4m @ 24.6 g/t Au & 82.8 g/t Ag from 95m (TBM0161) and 16m @ 3.74 g/t Au & 15.1 g/t Ag from 57m (TBM0289) and 8m @ 9.34 g/t Au & 13.6 g/t Ag from 90m (TBM0290).⁴

Figure 3 - Tolmer 'gold zone' cross-section B with anomalous Ag-Pb & key intersections

Emerging high-grade 'western silver' and 'eastern gold' footprints

Tolmer's 'western silver zone' is now host to numerous drilling assays exceeding 2,000 gram-metres (g-m) Ag, with key assays from this area also carrying material gold credits. These include:⁵

Table 2 - Key 'western silver zone' assays (Nov 2024, Jan-Feb / May-Jun 2025 and May-Jun 2026 drilling)⁵

Key assays from Tolmer's 'eastern gold zone' now include multiple broad, shallow high-grade gold assays:⁵

Table 3 - Key 'eastern gold zone' assays (Nov 2024, Jan-Feb / May-Jun 2025 and May-Jun 2026 drilling)⁵

Next steps for Tolmer

Barton will now focus on structural interpretation and metallurgical analysis for Tolmer.

Analysis of the petrology of Tolmer's silver mineralisation is already underway to inform early perspectives on potential recoverability, with full metallurgical testwork to start using samples composited from current drilling.

Barton will also prepare an updated geological interpretation to inform modelling of the mineralisation, its key controls, the optimal design of follow up drilling programs, and early views of potential mining methods.

The Company will provide further updates on these programs and analyses in due course.

Authorised by the Board of Directors of Barton Gold Holdings Limited.

For further information, please contact:

¹ Refer to ASX announcement dated 27 March 2025

² Refer to ASX announcements dated 27 Aug 2024, and 30 Jan, 27 Mar, 16 Apr, 5 / 25 Aug, 24 Sep and 9 Dec 2025, and 5 May 2026

³ Refer to ASX announcements dated 19 May and 11 June 2026; refer to JORC tables in annexures for full details of all significant intersections

⁴ Refer to ASX announcements dated 27 Aug 2024, and 30 Jan, 27 Mar, 16 Apr, 5 Aug and 9 Dec 2025, and the results in this announcement

⁵ Refer to ASX announcements dated 27 Aug 2024, and 30 Jan, 27 Mar, 16 Apr, 5 Aug and 9 Dec 2025, and the results in this announcement

Competent Persons Statement

The information in this announcement that relates to Exploration Results for the Tarcoola Gold Project (including drilling, sampling, geophysical surveys and geological interpretation) is based upon, and fairly represents, information and supporting documentation compiled by Mr Marc Twining BSc (Hons). Mr Twining is an employee of Barton Gold Holdings Ltd and is a Member of the Australasian Institute of Mining and Metallurgy Geoscientists (AusIMM Member 112811) and has sufficient experience with the style of mineralisation, the deposit type under consideration and to the activity being undertaken, 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" (The JORC Code). Mr Twining consents to the inclusion in this announcement of the matters based upon this information in the form and context in which it appears.

About Barton Gold

Barton Gold is an ASX, OTC and Frankfurt Stock Exchange listed Australian gold developer targeting future gold production of 150,000ozpa with 2.2Moz Au & 3.1Moz Ag JORC Mineral Resources (79.9Mt @ 0.87g/t Au), brownfield mines, and 100% ownership of the region's only gold mill in the renowned Gawler Craton of South Australia.^*

Challenger Gold Project 313koz Au + fully permitted Central Gawler Mill (CGM) Tarcoola Gold Project 20koz Au in fully permitted open pit mine near CGM Tolmer discovery grades up to 84g/t Au & 17,600g/t Ag Tunkillia Gold Project 1.6Moz Au & 3.1Moz Ag JORC Mineral Resources Competitive 120kozpa gold & 250kozpa silver project Wudinna Gold Project 279koz Au project located southeast of Tunkillia Significant optionality, adjacent to main highway

Competent Persons Statement & Previously Reported Information

The information in this announcement that relates to the historic Exploration Results and Mineral Resources as listed in the table below is based on, and fairly represents, information and supporting documentation prepared by the Competent Person whose name appears in the same row, who is an employee of or independent consultant to the Company and is a Member or Fellow of the Australasian Institute of Mining and Metallurgy (AusIMM), Australian Institute of Geoscientists (AIG) or a Recognised Professional Organisation (RPO). Each person named in the table below has sufficient experience which is relevant to the style of mineralisation and types of deposits under consideration and to the activity which he has undertaken to qualify as a Competent Person as defined in the JORC Code 2012 (JORC).

The information relating to historic Exploration Results and Mineral Resources in this announcement is extracted from the Company's Prospectus dated 14 May 2021 or as otherwise noted, available from the Company's website at www.bartongold.com.au or on the ASX website www.asx.com.au. The Company confirms that it is not aware of any new information or data that materially affects the Exploration Results and Mineral Resource information included in previous announcements and, in the case of estimates of Mineral Resources, that all material assumptions and technical parameters underpinning the estimates, and any production targets and forecast financial information derived from the production targets, continue to apply and have not materially changed. In accordance with ASX Listing Rule 5.19.2, the Company further confirms that the material assumptions underpinning any production targets and the forecast financial information derived therefrom continue to apply and have not materially changed. The Company confirms that the form and context in which the applicable Competent Persons' findings are presented have not been materially modified from the previous announcements.

Cautionary Statement Regarding Forward-Looking Information

This document may contain forward-looking statements. Forward-looking statements are often, but not always, identified by the use of words such as "seek", "anticipate", "believe", "plan", "expect", "target" and "intend" and statements than an event or result "may", "will", "should", "would", "could", or "might" occur or be achieved and other similar expressions. Forward-looking information is subject to business, legal and economic risks and uncertainties and other factors that could cause actual results to differ materially from those contained in forward-looking statements. Such factors include, among other things, risks relating to property interests, the global economic climate, commodity prices, sovereign and legal risks, and environmental risks. Forward-looking statements are based upon estimates and opinions at the date the statements are made. Barton undertakes no obligation to update these forward-looking statements for events or circumstances that occur subsequent to such dates or to update or keep current any of the information contained herein. Any estimates or projections as to events that may occur in the future (including projections of revenue, expense, net income and performance) are based upon the best judgment of Barton from information available as of the date of this document. There is no guarantee that any of these estimates or projections will be achieved. Actual results will vary from the projections and such variations may be material. Nothing contained herein is, or shall be relied upon as, a promise or representation as to the past or future. Any reliance placed by the reader on this document, or on any forward-looking statement contained in or referred to in this document will be solely at the reader's own risk, and readers are cautioned not to place undue reliance on forward-looking statements due to the inherent uncertainty thereof.

^* Refer to Barton Prospectus dated 14 May 2021 and ASX announcement dated 8 September 2025. Total Barton JORC (2012) Mineral Resources include 1,049koz Au (39.7Mt @ 0.82 g/t Au) in Indicated category and 1,186koz Au (40.2Mt @ 0.92 g/t Au) in Inferred category, and 3,070koz Ag (34.5Mt @ 2.80 g/t Ag) in Inferred category as a subset of Tunkillia gold JORC (2012) Mineral Resources.

JORC Table 1 - Tarcoola Gold Project

Section 1 Sampling Techniques and Data