New High-Grade Domain Discovered at Cuffley
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
Level 4, 66 Kings Park Rd, West Perth WA 6005, AUSTRALIA (PO Box 768, West Perth WA 6872, AUSTRALIA)
Telephone: +61 8 9227 5677 alkres.com [email protected]
ASX ANNOUNCEMENT
24 August 2026
New High-Grade Domain Discovered at Cuffley
Perth, Western Australia - 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 doma in 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 h igh 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
o 580.9g/t gold and 24% antimony over 0.61m (ETW 0.54m) in AD270
o 168.9g/t gold and 33.5% antimony over 0.9m (ETW 0.78m) in AD265
o 60.1g/t gold and 15.2% antimony over 1.26m (ETW 1.17m) in AD292
o 124g/t gold and 48.6% antimony over 0.23m (ETW 0.22m) in AD275
From Sub KC
o 28.2g/t gold and 0% antimony over 0.99m (ETW 0.82m) in CSK044
o 73.2g/t gold and 18.8% antimony over 0.19m (ETW 0.18m) in CSK043
o 192g/t gold and 0% antimony over 0.17m (ETW 0.07m) in CSK043
o 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 ex tract value. We will continue seeking this new
mineralisation alongside generating new targets within our leases.”
New High -Grade Domain Discovered at Cuffley – 24 August 2026
2/24
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 3k m 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 GDA 2020 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
New High -Grade Domain Discovered at Cuffley – 24 August 2026
3/24
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 A nticline. 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 d eveloped 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 low er 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:
o 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)
o 168.9g/t gold and 33.5% antimony over 0.9m (ETW 0.78m) in AD265
o 60.1g/t gold and 15.2% antimony over 1.26m (ETW 1.17m) in AD292
o 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.
New High -Grade Domain Discovered at Cuffley – 24 August 2026
4/24
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:
o 28.2g/t gold and 0% antimony over 0.99m (ETW 0.82m) in CSK044
o 73.2g/t gold and 18.8% antimony over 0.19m (ETW 0.18m) in CSK043
o 192g/t gold and 0% antimony over 0.17m (ETW 0.07m) in CSK043
o 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 favourab le east-dipping fold limb. These two holes intercepted
moderate grades in the Adder Fault, located just into the wall from the collar point.
Conversely, t he 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.
New High -Grade Domain Discovered at Cuffley – 24 August 2026
5/24
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.
New High -Grade Domain Discovered at Cuffley – 24 August 2026
6/24
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.
New High -Grade Domain Discovered at Cuffley – 24 August 2026
7/24
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 t he
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.
New High -Grade Domain Discovered at Cuffley – 24 August 2026
8/24
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.