(GLOBE NEWSWIRE via COMTEX) --
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
- 23 new holes have been drilled in an unmined area between the historical Cuffley north and south high-grade grade panels, and 17 additional holes have targeted the Sub KC domain at depth below the deposit
- A new grade pod with areas of very high grade gold and antimony was identified in the Cuffley infill area, in a sparsely drilled zone previously thought to contain low grade due to the influence of a crosscutting fault
- Additional high grade infill intercepts have made in the Sub KC system, and the first target testing holes looking for repetitions of the structural setup have been drilled
- The Cuffley pod is readily accessible from existing infrastructure and is being incorporated into the mine schedule
Assay Highlights
- From Cuffley - 580.9g/t gold and 24% antimony over 0.61m (ETW 0.54m) in AD270
- 168.9g/t gold and 33.5% antimony over 0.9m (ETW 0.78m) in AD265
- 60.1g/t gold and 15.2% antimony over 1.26m (ETW 1.17m) in AD292
- 124g/t gold and 48.6% antimony over 0.23m (ETW 0.22m) in AD275
- From Sub KC
- 28.2g/t gold and 0% antimony over 0.99m (ETW 0.82m) in CSK044
- 73.2g/t gold and 18.8% antimony over 0.19m (ETW 0.18m) in CSK043
- 192g/t gold and 0% antimony over 0.17m (ETW 0.07m) in CSK043
- 16.1g/t gold and 12.7% antimony over 0.37m (ETW 0.34m) in CSK048
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:
- Early, laminated bedding parallel quartz veins (Figure 7, CSK043), reactivated and dilated during the mineralisation, the later quartz-stibnite vein generation is often discreet and confined to one side of the vein with the lamination adhering to the other contact. Gold is commonly found in the laminations of the older quartz generation.
- Single-generation quartz veins in subvertical orientations, linking between the laminated, bedded veins (Figure 7, CSK044). These structures most likely developed under extensional stress contemporaneous with the time of mineralisation.
- East-dipping veins found on the western limb of the Cuffley Anticline, crosscutting the bedding at a high angle. These veins appear to be exploiting an earlier axial, spaced fabric including jointing and minor faulting developed at the time of anticline formation. The existence of these veins indicate that while the Lyre Fault has some post-mineralisation movement, it is not necessarily a hard boundary to mineralisation in this domain.
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:
- 580.9g/t gold and 24% antimony over 0.61m (ETW 0.54m) in AD270 - Including 0.25m @ 1360g/t gold & 19.7% antimony (Figure 6)
- 168.9g/t gold and 33.5% antimony over 0.9m (ETW 0.78m) in AD265
- 60.1g/t gold and 15.2% antimony over 1.26m (ETW 1.17m) in AD292
- 124g/t gold and 48.6% antimony over 0.23m (ETW 0.22m) in AD275
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:
- 28.2g/t gold and 0% antimony over 0.99m (ETW 0.82m) in CSK044
- 73.2g/t gold and 18.8% antimony over 0.19m (ETW 0.18m) in CSK043
- 192g/t gold and 0% antimony over 0.17m (ETW 0.07m) in CSK043
- 16.1g/t gold and 12.7% antimony over 0.37m (ETW 0.34m) in CSK048
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 Bjorkdal underground gold mine northwest of Skelleftea 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 ID From (m) To (m) Interval (m) Estimated Au (g/t) Sb (%) Gold-equiv. Interpreted
True Width (m) grade diluted Vein
to 1.8 m (g/t)
AD265 78.31 79.21 0.90 0.78 168.9 33.5 107.4 Cuffley
AD266 97.50 98.70 1.20 0.88 6.7 2.4 6.1 Cuffley
AD270 75.70 76.31 0.61 0.54 580.9 24.0 192.0 Cuffley
Including 76.06 76.31 0.25 0.20 1360.0 19.7
AD272 80.59 80.96 0.37 0.29 0.0 0.0 0.0 Cuffley
AD273 89.53 89.69 0.16 0.13 4.2 1.2 0.5 Cuffley
AD274 72.42 72.56 0.14 0.13 0.8 2.4 0.5 Cuffley
AD275 76.11 76.34 0.23 0.22 124.0 48.6 28.8 Cuffley
AD276 80.78 80.95 0.17 0.14 0.5 0.0 0.0 Cuffley
AD277 80.65 81.03 0.38 0.33 17.8 0.9 3.6 Cuffley
AD278 73.81 74.46 0.65 0.61 6.9 0.9 3.1 Cuffley
AD283 82.52 83.02 0.50 0.41 0.1 0.1 0.1 Cuffley
AD286 81.76 82.08 0.32 0.26 0.0 0.0 0.0 Cuffley
AD290 105.50 105.62 0.12 0.07 38.5 19.1 3.5 Cuffley
AD292 72.74 74.00 1.26 1.17 60.1 15.2 62.9 Cuffley
AD293 95.81 96.07 0.26 0.18 0.0 0.0 0.0 Cuffley
CSK043 503.40 503.66 0.26 0.23 0.1 0.2 0.1 Sub KC 401
CSK044 496.86 497.42 0.56 0.51 0.1 1.2 0.9 Sub KC 401
CSK048 522.80 523.17 0.37 0.34 16.1 12.7 8.8 Sub KC 401
CSK032 461.24 461.42 0.18 0.15 0.0 0.0 0.0 Sub KC 402
CSK042 533.22 533.44 0.22 0.20 0.1 0.0 0.0 Sub KC 402
CSK043 511.23 511.42 0.19 0.18 73.2 18.8 12.0 Sub KC 402
CSK044 504.42 505.27 0.85 0.84 1.6 0.1 0.9 Sub KC 402
CSK046 525.64 525.80 0.16 0.15 0.3 0.0 0.0 Sub KC 402
CSK048 531.03 531.23 0.20 0.19 10.6 26.2 7.6 Sub KC 402
CSK042 497.87 498.00 0.13 0.12 0.0 0.0 0.0 Sub KC 405
CSK043 491.10 491.21 0.11 0.10 3.2 0.0 0.2 Sub KC 405
CSK044 484.73 485.03 0.30 0.30 1.9 0.0 0.3 Sub KC 405
CSK048 508.43 508.56 0.13 0.12 22.9 11.3 3.4 Sub KC 405
CSK043 547.70 549.09 1.39 1.15 0.7 0.3 0.8 Sub KC 410
CSK044 536.70 537.69 0.99 0.82 28.2 0.0 12.9 Sub KC 410
CSK045 549.38 549.63 0.25 0.20 8.6 0.3 1.0 Sub KC 410
CSK045W1 543.82 547.08 3.26 2.70 1.0 0.7 2.7 Sub KC 410
CSK043 712.30 712.47 0.17 0.07 192.0 0.0 6.9 Sub KC 420
CSK045 670.90 671.90 1.00 0.40 0.2 0.0 0.1 Sub KC 420
CSK035 942.41 942.54 0.13 0.10 0.0 0.0 0.0 Sub KC 425
CSK040 667.34 668.03 0.69 0.40 0.1 0.0 0.0 Sub KC 425
CSK040W1 634.05 636.00 1.95 1.24 3.2 0.0 2.2 Sub KC 425
CSK042 624.48 624.71 0.23 0.12 52.3 0.0 3.6 Sub KC 425
AD269 106.20 108.38 2.18 0.78 2.8 1.0 2.3 Cuffley Assoc.
AD269 111.51 111.81 0.30 0.12 1.8 11.4 2.0 Cuffley Assoc.
AD277 77.92 78.03 0.11 0.09 5.9 14.7 2.1 Cuffley Assoc.
AD277 79.23 79.67 0.44 0.36 2.3 1.9 1.4 Cuffley Assoc.
AD279 78.92 79.13 0.21 0.20 30.3 21.7 8.9 Cuffley Assoc.
AD279 80.62 81.06 0.44 0.20 99.1 0.1 11.0 Cuffley Assoc.
AD279 85.66 86.46 0.80 0.59 4.4 0.2 1.6 Cuffley Assoc.
AD281 119.20 119.54 0.34 0.25 40.6 3.6 6.8 Cuffley Assoc.
AD291 170.25 170.70 0.45 0.10 15.9 5.7 1.7 Cuffley Assoc.
AD292 79.65 79.79 0.14 0.11 22.1 0.0 1.3 Cuffley Assoc.
AD294 165.19 165.30 0.11 0.08 7.0 8.0 1.1 Cuffley Assoc.
AD294 177.26 177.58 0.32 0.17 4.7 19.9 4.9 Cuffley Assoc.
CSK036 4.58 4.76 0.18 0.15 2.0 38.4 7.9 Adder Ft Assoc.
CSK040 725.30 726.00 0.70 0.57 7.3 0.0 2.3 Sub KC Assoc.
CSK043 487.70 487.83 0.13 0.11 6.7 28.6 4.7 Sub KC Assoc.
CSK043 518.47 518.60 0.13 0.11 2.3 7.3 1.2 Sub KC Assoc.
CSK044 533.36 533.56 0.20 0.20 89.9 0.0 9.9 Sub KC Assoc.
CSK044 573.44 574.32 0.88 0.85 7.2 0.0 3.4 Sub KC Assoc.
CSK045W1 538.15 538.48 0.33 0.32 25.4 5.7 7.1 Sub KC Assoc.
CSK045W1 549.90 550.25 0.35 0.31 7.3 0.0 1.3 Sub KC Assoc.
CSK045W1 554.05 554.63 0.58 0.55 3.5 0.0 1.1 Sub KC Assoc.
CSK048 537.98 538.20 0.22 0.21 4.3 2.1 1.1 Sub KC Assoc.
Notes
1. The AuEq (gold equivalent) grade is calculated using the following formula:
AuEq g per t = Au g per t + Sb% x Sb price per 10kg x Sb processing recovery
Au price per g x Au processing recovery
Prices and recoveries used: Au $/oz = 2,500 (Au US$/gram = 80.39); Sb $/t = 19,000 (Sb US$/10kg = 190); Au Recovery = 91% and; Sb Recovery = 92%. The Au recovery assumption and Sb recovery assumption is based on established processing and sales in respect of Costerfield. It is the Company's opinion that all elements included in the metal equivalent calculation have a reasonable potential to be recovered and sold.
2. The estimated true width of composites that are not interpreted to be connected to a major vein (identified as "Other" in the above table) have been calculated using a generic, conservative intercept angle (alpha angle) of 45 degrees.
3. Composites that are not interpreted to be connected to a major vein and are below 1 g/t AuEq when diluted to 1.8m are not considered significant and are not recorded here.
4. Gold-equivalent grades for intervals with estimated true width >1.8m are not diluted.
Drill hole collar details from the Cuffley and Sub KC drilling at Costerfield covered in this release:
Hole ID Northing Easting Elevation Depth Azimuth Dip Date Completed
AD265 4806 15237 968 140.10 314.1 -0.3 2/01/2026
AD266 4806 15238 968 129.00 323.1 -12.6 5/01/2026
AD269 4806 15239 968 142.80 331.2 -19.3 6/02/2026
AD270 4801 15237 969 121.73 308.1 14.9 13/01/2026
AD272 4802 15237 969 118.24 321.4 9.1 16/01/2026
AD273 4806 15238 968 137.16 321.7 -6.5 12/02/2026
AD274 4799 15237 969 104.30 274.9 17.9 17/01/2026
AD275 4800 15237 968 121.79 301.8 -2.0 18/01/2026
AD276 4806 15238 968 95.20 310.7 -9.0 25/01/2026
AD277 4800 15238 969 156.09 305.2 24.0 21/01/2026
AD278 4801 15237 969 145.91 291.2 21.0 23/01/2026
AD279 4805 15238 971 98.02 295.0 34.2 26/01/2026
AD280 4806 15238 971 151.98 314.8 35.2 29/01/2026
AD281 4806 15239 967 161.44 327.3 -28.1 10/02/2026
AD283 4806 15238 968 164.60 316.9 -10.0 1/02/2026
AD284 4806 15238 968 149.50 325.3 -19.8 4/02/2026
AD285 4806 15238 969 160.77 315.5 15.3 25/02/2026
AD286 4806 15238 970 157.77 317.7 23.6 23/02/2026
AD290 4806 15239 968 186.50 334.9 -14.1 15/02/2026
AD291 4806 15239 968 182.90 338.0 -22.0 20/02/2026
AD292 4806 15237 969 128.02 307.1 4.8 23/04/2026
AD293 4806 15239 969 122.30 331.7 6.9 26/04/2026
AD294 4806 15238 970 179.10 327.4 18.9 29/04/2026
CSK032 5035 15301 913 899.50 274.9 -71.5 27/02/2024
CSK033 5035 15301 913 602.62 291.2 -67.0 19/03/2024
CSK034 4489 15463 1030 839.40 263.5 -72.1 31/01/2025
CSK034W1 4489 15463 1030 940.00 263.5 -72.1 8/02/2025
CSK035 4489 15463 1030 995.57 287.9 -79.0 13/03/2025
CSK036 5710 14939 945 872.50 133.8 -33.8 10/03/2025
CSK037 5710 14939 944 881.35 133.0 -49.4 17/05/2025
CSK040 4744 15474 865 732.57 290.0 -55.6 9/06/2025
CSK040W1 4744 15474 865 656.40 290.0 -55.6 21/06/2025
CSK042 4758 15461 865 667.12 302.4 -50.1 22/06/2025
CSK043 4757 15461 865 934.90 296.3 -46.0 31/07/2025
CSK044 4744 15474 865 668.01 280.3 -48.0 21/09/2025
CSK045 4756 15461 865 760.50 285.2 -52.6 29/08/2025
CSK045W1 4756 15461 865 600.00 285.2 -52.6 7/09/2025
CSK046 4757 15461 865 659.14 297.6 -48.1 26/09/2025
CSK048 4745 15474 866 752.50 298.9 -44.0 20/10/2025
CSK049 4745 15474 865 760.22 302.2 -53.0 8/11/2025
Notes:
- Coordinate System: Costerfield Local Mine Grid
Appendix 2 - JORC Code, 2012 Edition - Table 1
Section 1 Sampling Techniques and Data
Criteria JORC Code explanation Commentary
Sampling techniques - Nature and quality of sampling (e.g. cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc.). These examples should not be taken as limiting the broad meaning of sampling. Sampling of Au and Sb mineralisation is from diamond drill core (HQ2 and NQ2).
- Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used. Due to the discrete mineralisation of the deposit, not all diamond drill core was required to be sampled. Sample intervals were determined and marked on the core by Alkane geologists using the following general rules:
- Aspects of the determination of mineralisation that are Material to the Public Report. - All stibnite-bearing veins are sampled.
- In cases where 'industry standard' work has been done this would be relatively simple (e.g. 'reverse circulation drilling was used to obtain 1 m samples from which 3 kg was pulverised to produce a 30 g charge for fire assay'). In other cases more explanation may be required, such as where there is coarse gold that has inherent sampling problems. Unusual commodities or mineralisation types (e.g. submarine nodules) may warrant disclosure of detailed information. - Intersections of polyphase breccias, stockwork veins, laminated quartz veins or massive quartz veins were routinely sampled.
- A waste sample is taken either side of the mineralized vein (30-100 cm).
- Siltstone is sampled where disseminated arsenopyrite is prevalent.
- Fault gouge zones were sampled at the discretion of the geologist.
Diamond core sampling intervals were standardised wherever possible and ranged from 5 cm to 1 m in length. Diamond drill core samples have been cut in half using the orientation line or cut line, with a consistent side of the cut core selected for assay to ensure unbiased sampling. The methodology was validated by the Costerfield QA/QC protocols. No sampling instruments required calibration.
Assays were completed by On Site in Bendigo, which is independent of Alkane and holds current ISO/IEC 17025 accreditation. The general methods were as follows:
- Gold grades were determined by either fire assay (25 g charge) with an AAS finish, screen fire assay or Chrysos photon assay technology.
- Antimony concentrations were determined using an aqua regia based acid digest with an AAS finish.
Drilling techniques - Drill type (e.g. core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc) and details (e.g. core diameter, triple or standard tube, depth of diamond tails, face-sampling bit or other type, whether core is oriented and if so, by what method, etc.). Deepcore Drilling is the drilling contractor utilised for the whole of this project within the reporting period. All diamond drilling was completed from underground and was completed using LM90 drill rigs utilising HQ2 and NQ2 diameters. Core orientation is performed each run, typically using an AXIS Champ Ori kit.
Drill sample recovery - Method of recording and assessing core and chip sample recoveries and results assessed. Diamond drilling was routinely checked for core loss during both drilling and sampling. Core loss blocks were added by drillers and then checked by geologists or field technicians when the core was measured, and depth marks made. If problems were encountered with recovery and core block depths, the drill shift supervisor was advised and depth marking stopped until the issue was rectified.
- Measures taken to maximise sample recovery and ensure representative nature of the samples. No relationship between grade and sample recovery has been established. Ore zones with poor recovery are redrilled until a representative sample is achieved.
- Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse material.
Logging - Whether core and chip samples have been geologically and geotechnically logged to a level of detail to support appropriate Mineral Resource estimation, mining studies and metallurgical studies. All drill core was geologically logged as full core for the relevant rock quality designation, lithology, structural data, and sample intervals.
- Whether logging is qualitative or quantitative in nature. Core (or costean, channel, etc.) photography. Data capture was digital into the AcQuire software using validated codes.
- The total length and percentage of the relevant intersections logged. All drill core was photographed wet with high resolution photographs stored on the site's server, which is routinely backed-up.
Sub-sampling techniques and sample preparation - If core, whether cut or sawn and whether quarter, half or all core taken. Diamond core sampling intervals were standardised wherever possible and ranged from 5 cm to 1 m in length. Diamond drill core samples have been halved for sampling (whole core sampled if representative halving was not possible) guided by the orientation line or a cut line, with a consistent side of the cut core selected for assay to ensure unbiased sampling.
- If non-core, whether riffled, tube sampled, rotary split, etc., and whether sampled wet or dry. The following sample preparation activities were undertaken by Alkane staff for both diamond drill core and underground channel samples:
- For all sample types, the nature, quality and appropriateness of the sample preparation technique. - Sample information and characteristics were measured, logged, recorded in the acQuire database and assigned a unique sample ID.
- Quality control procedures adopted for all sub-sampling stages to maximise representivity of samples. - Sample material was placed into a calico bag previously marked with the unique sample ID.
- Measures taken to ensure that the sampling is representative of the in situ material collected, including for instance results for field duplicate/second-half sampling. - Calico bags were loaded into plastic bags such that the plastic bags weighed less than 10 kg.
- Whether sample sizes are appropriate to the grain size of the material being sampled. - An assay submission sheet was generated and placed into the plastic bag.
- Plastic bags containing samples were sealed with a metal or plastic tie and transported to On Site in Bendigo via private courier or Alkane staff.
The following sample preparation activities were undertaken by On Site staff:
- Samples were received and checked for labelling, missing samples, etc. against the submission sheet.
- If the sample batch matched the submission sheet, sample metadata were entered into On Site's LIMS. In the event that discrepancies were noted, Mandalay Resources was contacted by On Site to resolve the discrepancy prior to further work commencing. Records of all discrepancies and corrective actions taken are recorded by the Mandalay Resources database administrator.
- A job number was assigned, and worksheets and sample bags were prepared.
- Samples were placed in an oven and dried overnight at 106°C.
- Samples were weighed and recorded.
- The entire dried sample was crushed using a Rocklabs Smart BOYD Crusher RSD Combo with a jaw closed side setting of 2 mm.
- If the dried sample weight was less than 3 kg, the entire sample was retained for pulverisation. If the dried sample weight was greater than 3 kg, the sample was spilt to 3 kg using the rotary splitter that is incorporated in the BOYD crusher.
- Rejects from splits greater than 3 kg were retained as coarse rejects in labelled calico bags and returned to Mandalay Resources.
- The 3 kg sample was then pulverised in an Essa LM5 Pulverising Mill to 90% passing 75 um.
For fire assay and base metal samples:
- The 3 kg pulverised samples were then subsampled to take a master 200 g pulp split for assay by a manual scooping procedure across the full width and depth of the mill bowl and loaded sequentially into labelled pulp packets.
For photon assay:
- The 3 kg pulverised samples were then subsampled to fill a 280 g photon assay jar by a manual scooping procedure across the full width and depth of the mill bowl.
For all methods:
- For every 21 primary samples, a sample was randomly selected by LIMS and a duplicate 200 g split for fire assay or second jar for photon assay was submitted for analysis using the same analytical procedure as the primary sample.
- The remaining pulp was returned to its sample bag and then returned to Mandalay Resources for retention following the completion of assay.
A quarterly check-assay program is in place to monitor the representative nature of sampling and assay methodology.
Quality of assay data and laboratory tests - The nature, quality and appropriateness of the assaying and laboratory procedures used and whether the technique is considered partial or total. The assaying protocols used at Costerfield have been developed to ensure expected levels of accuracy and precision are met for the style of mineralisation tested and utilised in the MRE.
- For geophysical tools, spectrometers, handheld XRF instruments, etc., the parameters used in determining the analysis including instrument make and model, reading times, calibrations factors applied and their derivation, etc. Samples were assayed for gold, antimony, arsenic, and iron using representative partial digest methodologies:
- Nature of quality control procedures adopted (e.g. standards, blanks, duplicates, external laboratory checks) and whether acceptable levels of accuracy (i.e. lack of bias) and precision have been established. - Gold grades were determined either by a 25g charge with lead flux fire assay and an AAS finish, or by Chrysos photon assay technology.
- Antimony, iron and arsenic concentrations were determined using an aqua regia based acid digest with an AAS finish.
The quality control procedures utilised at Costerfield used CRMs prepared by commercial laboratories Geostats and OREAS.
CRMs were either prepared using Costerfield material or were otherwise matrix matched to ensure a representative nature.
At least one CRM was submitted with every batch of diamond core samples and typically at a rate of 1 standard per 25 samples. Up to six CRMs covering the expected ranges of gold and antimony mineralisation were in rotation during routine sampling.
An assay result for a CRM was considered acceptable when the returned assay fell within three standard deviations of the CRM certification grade. Outside this range, the CRM assay was considered to have failed and all significant mineralised samples within the batch were re-assayed, where significant grades were defined as mineralised samples that may have a material-impact in future resource estimates. All actions or outcomes were recorded as comments in the QA/QC register.
Alkane submitted uncrushed samples of basalt as blank material sourced from Geostats into assay sample lots, at a rate of 1 in every 30 samples, to test for contamination during sample preparation.
Copyright (C) 2026 GLOBE NEWSWIRE. All rights reserved.
