New High-Grade Domain Discovered at Cuffley

About this update from Alkane Resources Ltd

PERTH, Australia, Aug. 23, 2026 (GLOBE NEWSWIRE) -- Alkane Resources Limited (ASX: ALK; TSX: ALK; OTCQX: ALKRY) ('Alkane' or 'the Company') is pleased to announce the latest exploration results highlighting the discovery of a new high-grade zone of the Cuffley Lode, and drilling results from the Sub-KC domain at depth below the Augusta mine and the Costerfield property in Victoria, Australia Program Summary Assay Highlights Alkane Managing Director & CEO, Nic Earner, said: "This discovery of unmined high-grade material directly adjacent one of Costerfield's top-shelf historical orebodies showcases the importance of Alkane's directive of revisiting and challenging old models and preconceptions surrounding mineralisation to extract value. We will continue seeking this new mineralisation alongside generating new targets within our leases." Costerfield Gold-Antimony Field Alkane Resources Ltd 100% The Costerfield gold-antimony deposit was discovered in 1861, antimony having been already identified in the district as early as 1853 as prospectors attracted to the McIvor (Heathcote) alluvial gold rush began to explore the surrounding hills for the primary deposits. Several lodes along a 3km corridor were rapidly opened up, the bulk of historical production coming from leases at the northern end of the field; the Costerfield (Main), Bombay and Minerva mines. Production from these mines primarily took place in two phases, between 1861-1883 and 1903-1924, and a short-lived attempt at redeveloping the mine occurred between 1933-1939. Modern mining has been continuous since 2006, when Australian Gold Development commenced underground operations at Augusta, at the southern end of the field. AGD's Costerfield operation was purchased by Mandalay Resources in 2010, and extraction of the vertically continuous vein system has progressively moved north. Firstly from the initial Augusta series of lodes, to Cuffley and N Lode in 2014 and the Brunswick in 2018. Costerfield's current locus of mining is beneath the Costerfield, Minerva and Bombay group of mines, where Mandalay's high-grade Youle and Shepherd lodes were accessed in 2019. Figure 1. Regional map of the Costerfield Project in GDA2020 grid showing Alkane tenements and the main corridors of mineralisation identified, highlighting the location of the Cuffley and Sub KC deposits. Deposit Geology The Cuffley and Sub KC deposits are found within the Central Corridor of deposits at Costerfield. This corridor approximately traces the apex of the Costerfield Dome, a structural high which consists of Silurian marine siltstones with turbiditic intervals becoming common towards the base of the known sequence. The Cuffley Lode occupies a vertical shear, running along a N-S field-scale anticline (Cuffley Anticline) next to the Augusta Deposit. The lode sits on the gently dipping western edge of its 200m-wide hinge zone, N Lode occupies the corresponding eastern axial zone with a steep east-dipping limb. Mineralisation at Cuffley is of the "classic" Costerfield style, consisting of quartz-carbonate veining grading to massive stibnite, gold being found in both quartz and stibnite. Updip, the Cuffley lode is truncated by the Mamushi/Flat Fault set, which offsets the mineralisation above eastward by approximately 40m, where it is known as the historical Alison deposit. The Alison mineralisation is itself bounded updip by the major west-dipping Adder Fault thrust. The footwall of the Cuffley system is delineated by the similarly west-dipping King Cobra Fault thrust, which breaches and offsets the Cuffley anticline. Down-dip from Cuffley, westward along the King Cobra Fault plane, mineralisation resumes with the Sub-KC deposit. Sub-KC occupies the steeply dipping east limb of the continuation of the Cuffley Anticline. If the approximately 300m of offset along the fault plane is restored, reconstructing the anticline and stratigraphy, the Sub-KC deposit correlates very well with the downward continuation of N Lode. The axis of the anticline hosts a strong gougey shear termed the Lyre Fault, which merges into the King Cobra Fault forming the hangingwall of the main Sub-KC domain between them. The Lyre Fault exhibits some clear post-mineralisation movement, evidenced by clasts of mineralised vein material in fault gouge recovered in earlier Sub-KC drilling. Most mineralisation associated with Sub KC sits in the immediate footwall of the Lyre Fault and reduces in tenor at distance from the fault plane. Strike control is not fully understood at this stage of drilling due to limited drilling orientations, but appear to be related to north-east trending splays from the Lyre Fault somewhat similar in nature to the East Fault at Cuffley. The most important of these are the Bird and Bustard Faults, represented on the Sub-KC long section below. The veins of the Sub-KC deposit generally fall into three categories: All veins have demonstrated the capability to host coarse, high-grade gold and varying amounts of massive stibnite. In general, antimony grades are of lesser importance within the Sub-KC deposit relative to other mined deposits at Costerfield, perhaps due to comparatively limited vein volumes which does not appear to influence gold prospectivity. "Rusty" gold after aurostibite is commonly observed, along with occasional veins containing native antimony metal (Figure 8) typically with small amounts of pyrrhotite. This assemblage indicates minor activity of a lower sulphur, relatively reduced ore fluid phase. Drilling Results - Cuffley 23 growth and infill holes have been completed, totalling 3,255m of diamond drill core. This activity resulted in 18 new intercepts on the mineralised structure, the remaining five fault blanking as the bounds of the new domain was explored. Four drillholes intercepted mineralisation grading over 10g/t gold equivalent over mining width: An additional four holes graded over 2g/t gold equivalent over mining width. Drilling Results – Sub KC Four target-testing holes were drilled for 3705.32m, and ten parent / two wedge growth and infill holes were completed for 8168.28m. Several ore-grade intercepts were made within the system, including: The target testing holes explored the footwall of the Lyre Fault along strike north and south of the main Sub-KC block, testing for repetitions in zones modelled to have favourable structural setup. The two holes drilled approximately 400m north of the main block found the Lyre Fault plane to have stepped eastward in position, faulting out much of the inferred favourable east-dipping fold limb. These two holes intercepted moderate grades in the Adder Fault, located just into the wall from the collar point. Conversely, the holes drilled approximately 300m south of the Sub-KC zone found an intact anticlinal position, without the presence of the expected Lyre Fault, which appears to be located further westward at this point. Both holes encountered veins with anomalous gold however no ore-grade intercepts were made. Figure 2. Long Section of the Cuffley System with major vein target envelopes displayed, recent drill traces and > 6g/t AuEq new intercepts labelled. New significant intercepts not associated with a named structure are represented as triangular icons. Older significant drill intercepts are displayed as smaller, unlabelled icons. Previous mining on the Cuffley Lode with face assays and depleted areas area are also shown. Figure 3. Long Section of the Sub-KC System with major vein target envelopes displayed, recent drill traces and > 6g/t AuEq new intercepts labelled. Older significant drill intercepts are displayed as smaller, unlabelled icons. New significant intercepts not associated with a named structure are represented as triangular icons. Figure 4. Plan Section of the Cuffley and Sub KC deposits with vein best fit traces displayed, recent drill traces and > 6g/t AuEq new intercepts labelled. Older significant drill intercepts are displayed as smaller, unlabelled icons. New significant intercepts not associated with a named structure are represented as triangular icons. Figure 5. Cross section looking north at mine northing 4900N showing the Cuffley and Sub-KC systems (veins represented schematically), and > 6g/t AuEq new intercepts labelled. Older significant drill intercepts are displayed as smaller, unlabelled icons. New significant intercepts not associated with a named structure are represented as triangular icons. Figure 6. Core tray photo of the high-grade Cuffley intercept in AD270. Note the very high gold interval of 1360g/t Au, and consistent high-grade antimony. Please refer to Appendix 1 for the relevant assay results relating to Figure 6. Figure 7. Core tray photographs of the Sub-KC 405 Lode intercepts from drillholes CSK043 (bottom) and CSK044 (top). Intervals with grade above detection levels are labelled. Note the bedding-parallel nature of the major veins, due to reactivation of early laminated quartz structures acting as host structure, and the additional occurrence of high grade visible gold in very narrow veinlets (CSK044, 537m). Please refer to Appendix 1 for the relevant assay results relating to Figure 7. Figure 8. Vein containing a significant volume of native antimony metal (metallic white) intercepted in CSK045W1 (538.15m). The vein also contained stibnite and pyrrhotite, and pyrite wallrock alteration can be seen in the image. Please refer to Appendix 1 for the relevant assay results relating to Figure 8. Future Plans The new grade pod at Cuffley has been integrated into the Costerfield mine plan and is scheduled to be mined. Considerable scope remains for further growth within the Sub KC domain with the structural information gained from the north and south target testing holes, however drilling will likely need to be undertaken from surface, or future development with improved intersection angles with the target areas. This document has been authorised for release to the market by Nic Earner, Managing Director. ABOUT ALKANE ‐ www.alkres.com ‐ ASX:ALK | TSX: ALK | OTCQX: ALKRY Alkane (ASX:ALK; TSX:ALK; OTCQX:ALKRY) is an Australia-based gold and antimony producer with a portfolio of three operating mines across Australia and Sweden. The Company has a strong balance sheet and is positioned for further growth. Alkane's wholly owned producing assets are the Tomingley open pit and underground gold mine southwest of Dubbo in Central West New South Wales, the Costerfield gold and antimony underground mining operation northeast of Heathcote in Central Victoria, and the Björkdal underground gold mine northwest of Skellefteå in Sweden (approximately 750 km north of Stockholm). Ongoing near-mine regional exploration continues to grow resources at all three operations. Alkane also owns the very large gold-copper porphyry Boda-Kaiser Project in Central West New South Wales and has outlined an economic development pathway in a Scoping Study. The Company has ongoing exploration within the surrounding Northern Molong Porphyry Project and is confident of further enhancing eastern Australia's reputation as a significant gold, copper and antimony production region. Competent Persons Statement Certain information in this announcement relating to Exploration Results has been previously released to the ASX (refer to ASX announcement dated 14 July 2026 titled 'Alkane Extends High Grade Gold Trend at Brunswick South') . Alkane confirms that it is not aware of any new information or data that materially affects the information included in those market announcements and that all material assumptions and technical parameters underpinning the estimates and Exploration Results in those announcements continue to apply and have not materially changed. The information in this report that relates to the Costerfield Exploration Results is based on, and fairly represents, information compiled and verified by Mr Chris Davis. Mr Davis is a Chartered Professional (Geology) of the Australasian Institute of Mining and Metallurgy (MAusIMM CP(Geo)), and a Member of the Australian Institute of Geoscientists (MAIG). Mr Davis has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the "Australian Code for Reporting of Exploration Results, Mineral Resources, and Ore Reserves" (JORC Code). For the purposes of National Instrument 43-101 – Standards of Disclosure for Mineral Projects ('NI 43-101'), the scientific and technical information contained in this announcement relating to the Costerfield Exploration Results has been prepared under the supervision of, and approved by, Mr Chris Davis, who is a "qualified person" as defined in NI 43-101. Mr Davis is employed by Alkane as Chief Geologist and, as an employee of Alkane, is not considered independent of Alkane within the meaning of NI 43-101. Mr Davis consents to the inclusion in this report of the matters based on his information in the form and context in which they appear. Cautionary Note Regarding Forward-Looking Information and Statements This announcement contains certain forward-looking information and forward-looking statements within the meaning of applicable securities legislation and may include future-oriented financial information or financial outlook information (collectively Forward-Looking Information). Actual results and outcomes may vary materially from the amounts set out in any Forward-Looking Information. As well, Forward-Looking Information may relate to: future outlook and anticipated events; expectations regarding exploration potential; production capabilities and future financial or operating performance, including AISC, investment returns, margins and share price performance; production and cost guidance and the timing thereof; issuing updated resources and reserves estimate and the timing thereof; the potential of Alkane to meet industry targets, public profile and expectations; and future plans, projections, objectives, estimates and forecasts and the timing related thereto. Forward-Looking Information is generally identified by the use of words like "will", "create", "enhance", "improve", "potential", "expect", "upside", "growth" and similar expressions and phrases or statements that certain actions, events or results "may", "could", or "should", or the negative connotation of such terms, are intended to identify Forward-Looking Information. Although Alkane believes that the expectations reflected in the Forward-Looking Information are reasonable, undue reliance should not be placed on Forward-Looking Information since no assurance can be provided that such expectations will prove to be correct. Forward-Looking Information is based on information available at the time those statements are made and/or good faith belief of the officers and directors of Alkane as of that time with respect to future events and are subject to risks and uncertainties that could cause actual results to differ materially from those expressed in or suggested by the Forward-Looking Information. Forward-Looking Information involves numerous risks and uncertainties. Such factors include, without limitation: risks relating to changes in the gold and antimony price. Forward-Looking Information is designed to help readers understand Alkane's views as of that time with respect to future events and speak only as of the date they are made. Except as required by applicable law, Alkane assumes no obligation to update or to publicly announce the results of any change to any forward-looking statement contained or incorporated by reference herein to reflect actual results, future events or developments, changes in assumptions or changes in other factors affecting the Forward-looking Information. If Alkane updates any one or more forward-looking statements, no inference should be drawn that the company will make additional updates with respect to those or other Forward-looking Information. All Forward-Looking Information contained in this announcement is expressly qualified in its entirety by this cautionary statement. Disclaimer Alkane has prepared this announcement based on information available to it. No representation or warranty, express or implied, is made as to the fairness, accuracy, completeness or correctness of the information, opinions or conclusions contained in this announcement. To the maximum extent permitted by law, none of Alkane, its directors, officers, employees, associates, advisers and agents, nor any other person accepts any liability, including, without limitation, any liability arising from fault or negligence on the part of any of them or any other person, for any loss arising from the use of this announcement or its contents or otherwise arising in connection with it. This announcement is not an offer, invitation, solicitation, or other recommendation with respect to the subscription for, purchase or sale of any security, and neither this announcement nor anything in it shall form the basis of any contract or commitment whatsoever. APPENDIX 1 – Tabulated Drilling Results Significant intercepts from the Cuffley and Sub KC drilling programs at Costerfield Drill hole collar details from the Cuffley and Sub KC drilling at Costerfield covered in this release: Notes: Appendix 2 - JORC Code, 2012 Edition – Table 1 Section 1 Sampling Techniques and Data Section 2 Reporting of Exploration Results Criteria listed in the Section 1 also apply to this section. CONTACT:  NIC EARNER, MANAGING DIRECTOR & CEO, ALKANE RESOURCES LTD, TEL +61 8 9227 5677 INVESTORS & MEDIA :  NATALIE CHAPMAN, CORPORATE COMMUNICATIONS MANAGER, TEL +61 418 642 556 Photos accompanying this announcement are available at: https://www.globenewswire.com/NewsRoom/AttachmentNg/adb351a0-caf6-4777-bc9e-cb50336502b7 https://www.globenewswire.com/NewsRoom/AttachmentNg/1d81658e-65cf-4048-8608-4b95b4fedaaf https://www.globenewswire.com/NewsRoom/AttachmentNg/085c1cf1-f271-4654-90f4-76ed3d2a06f4 https://www.globenewswire.com/NewsRoom/AttachmentNg/69045f50-831c-4367-bbf8-42141610be38 https://www.globenewswire.com/NewsRoom/AttachmentNg/a59f7d32-1bde-4a89-a114-1a8263eceea0 https://www.globenewswire.com/NewsRoom/AttachmentNg/7fcf21c8-cc10-4992-bcdc-5d26fa4757e3 https://www.globenewswire.com/NewsRoom/AttachmentNg/91fe17a8-2985-440c-9397-ecc378e4ff17 https://www.globenewswire.com/NewsRoom/AttachmentNg/9c94c948-755f-4ea5-83b5-f10a647effe7 https://www.globenewswire.com/NewsRoom/AttachmentNg/8c7f1cb1-e0aa-45c4-99a9-810efa4f926a

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