Announcement PDF dartmining.com.au 1 ASX:DTM Dart Mining NL ABN 84 119 904 880 Level 6, 412 Collins Street, Melbourne VIC 3000 E: jchirnside@dartmining.com.au M: +61 447 447 613 dartmining.com.au ASX Announcement 22 October 2026 MAIDEN DRILLING UNDERWAY AT WALWA TIN-TANTALUM PROJECT HIGHLIGHTS • 1,500m diamond drilling program has commenced at Walwa, testing an established tin-tantalum system that has never been drilled below 160m (Figures 1 and 2). • Target 1 – repeat tin-bearing dykes at depth: Drilling will first pass through the known tin-mineralised aplite-pegmatite dykes historically mined and drilled near surface, then test below existing drilling, where a seismic survey interpreted up to four additional dykes2 . • Target 2 - concealed greisen above the causative intrusion: A conceptual greisen target at the top of the interpreted causative intrusion, estimated to lie 400 m to 600 m below surface, well beyond the depth of historic drilling (Figure 3). • Nine drill pads have been surveyed and permitted along the existing access track network surrounding the historic workings, providing flexibility to expand the maiden drilling program. • Recent rock chip sampling at the historic pit returned up to 3.96% Sn and 165 ppm Ta (WWP002)3 . • Historic non-JORC Resource declarations on both the Walwa Tin, and McHargs Tungsten projects2,9 . Drilling will help define the work required to support a potential JORC (2012) Mineral Resource Estimate at Walwa. • Dart is advancing targeting work at both prospects and planning for maiden drilling in 2027, subject to access and approvals9,10 . Dart Mining NL (ASX:DTM) (Dart Mining or the Company) is pleased to advise that maiden diamond drilling commenced on 16th October 2026 at the 100%-owned Walwa Tin-Tantalum Project on EL007426 in northeast Victoria (the Project). The program moves Dart Mining’s priority project from data review and sampling into the drill phase, testing two targets beneath the historic Walwa (Mt Alwa) tin mine that sit below the 160m depth limit of all previous drilling. Dart Mining NL ASX Announcement 22 October 2026 dartmining.com.au 2 ASX:DTM Dart Mining's Chairman, James Chirnside, commented: “Decades of mining and historical exploration, including 150 drill holes, tell the same story: that the Walwa dykes are rich in tin, with associated tantalum and niobium. Yet none of that work went below 160m, and that is where we are now drilling, testing for repeats of the known mineralised dykes and for a larger tin-bearing greisen system above a causative intrusion beneath the historic workings. With tin supply tight and tantalum and niobium recognised as critical minerals, this is the right time to be drilling Victoria’s largest hardrock tin field at depth.” Figure 1 – Dart’s diamond drilling set up ready to commence drilling at Walwa Dart Mining NL ASX Announcement 22 October 2026 dartmining.com.au 3 ASX:DTM Figure 2 – Diamond drilling has commenced at Walwa – first core in trays to left of rig NEXT STEPS • Complete the 1,500m diamond drilling program at Walwa, testing two high-priority tin- tantalum targets2 . • Provide regular updates as drilling progresses, including geological observations from the core. • Report assay results once received, validated and compiled. • Undertake systematic rock chip and channel sampling of the tantalum-enriched albitite dykes at Snake Gully, assaying for Sn, Ta and Nb. • Complete field inspection and rock chip sampling at the McHargs tungsten and Hall’s gold prospects to verify historical results and plan future drilling9 . Dart Mining NL ASX Announcement 22 October 2026 dartmining.com.au 4 ASX:DTM Figure 3: Interpreted geology and high-priority tin mineralised targets at the Walwa tin mine (schematic, not to scale) Approved for release by the Board of Directors. For more information contact: James Chirnside Managing Director Dart Mining NL jchirnside@dartmining.com.au +61 419 605 842 InvestorHub Link Terry Bates Director Dart Mining NL tbates@dartmining.com.au Dart Mining NL ASX Announcement 22 October 2026 dartmining.com.au 5 ASX:DTM REFERENCES 1. Dart Mining NL (2026). Walwa Tin-Tungsten Project Site Visit and Observations. ASX announcement, 25 June 2026. 2. Dart Mining NL (2026). Priority Drilling Targets - Walwa Tin Project. ASX announcement, 25 August 2026. 3. Dart Mining NL (2026). High-Grade Tin and Tantalum Confirmed at Walwa. ASX announcement, 16 September 2026. 4. Bowen (1970). Mt Alwa and The Bounce Tin Mines. Mining and Geological Journal, Victoria. Vol 6, No 6. 5. Cochrane and Bowen (1971). Tin Deposits of Victoria. Geological Survey of Victoria, Bulletin No 60. 6. Union Corporation (Australia) Pty Ltd (1982). Six monthly report for the period September 1981 to March 1982, EL1248 and EL738. GSV report G30765 (EL1248-EL738_G30765_198203_Half.pdf). 7. Union Corporation (Australia) Pty Ltd (1983). Sixth six monthly report, EL1248, September 1983. GSV report G30768 (EL1248-EL738_G30768_198309_Half.pdf). 8. Hochwimmer, B., Geerdts, P. and Wanless, C. (2014). EL5462 Annual Report, 11 February 2014 to 30 June 2014. Alderan Resources Pty Ltd. GSV report G46899 (EL5462_G46899_201406_Annual.pdf). 9. Dart Mining NL (2026). Tungsten Project Update – Supplementary. ASX announcement, 11 August 2026. 10. Dart Mining NL (2026). Walwa Tin-Tungsten Project Site in NE Victoria Under Assessment. ASX announcement, 16 June 2026. All GSV reports are available at www.gsv.vic.gov.au (Earth Resources Regulation, GeoVic / Reports search). Competent Person’s Statement The information in this report has been prepared, compiled, and verified by Mr Andrew Dawes, who is a Member of the Australasian Institute of Mining and Metallurgy (CP, Geo) and a Member of the Australian Institute of Geoscientists (RP Geo). Mr Andrew Dawes is employed by AHD Resources and consults to Dart Mining NL. Mr Dawes has sufficient experience that is relevant to the style of mineralisation and type of deposits 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”. Mr. Dawes takes responsibility for the exploration results, and consents to the inclusion in the report of the matters based on his information in the form and context in which it appears. Forward-Looking Statement Certain statements contained in this document constitute forward-looking statements. Forward-looking statements include, but are not limited to, Dart Mining’s current expectations, estimates and projections about the industry in which Dart Mining operates, and beliefs and assumptions regarding Dart Mining’s future performance. Such forward-looking statements are based on a number of estimates and assumptions made by the Company and its consultants in light of experience, current conditions and expectations of future developments which the Company believes are appropriate in the current circumstances. When used in this document, words such as “anticipate”, “could”, “intends”, “estimate”, “potential”, “plan”, “seeks”, “may”, “should”, and similar expressions are forward-looking statements. Although Dart Mining believes that its expectations presented in these forward-looking statements are reasonable, such statements are subject to known and unknown risks, uncertainties and other factors, which may cause the actual results, achievements and performance of the Company to be materially different from the future results and achievements expressed or implied by such forward-looking statements. Investors are cautioned that forward-looking information is no guarantee of future performance and accordingly, investors are cautioned not to place undue reliance on these forward-looking statements. No new exploration results are reported in this release. The exploration results and historical estimates referred to in this release were previously reported in the Company’s ASX announcements of 25 June 2026, 25 August 2026 and 16 September 2026 and in the historical reports referenced above. Dart Mining confirms that it is not aware of any new information or data that materially affects the information included in those announcements, and that all material assumptions and technical parameters underpinning the historical estimates continue to apply and have not materially changed. Dart Mining NL ASX Announcement 22 October 2026 dartmining.com.au 6 ASX:DTM ABOUT DART MINING Dart Mining NL (ASX: DTM) is a diversified Australian explorer with a portfolio of critical minerals and gold projects in established mineral provinces in Victoria, Queensland and Western Australia. Its strategy is to create value through systematic, technically driven exploration across several commodities. Near-termactivity is centred on theWalwa Tin-Tantalum Project in northeast Victoria and the Triumph Gold Project in central Queensland. Walwa is 100% owned by Dart, and is Victoria's largest recorded primary hardrock tin field. Dart is testing a concealed greisen target beneath the historic open pit, interpreted as the deeper expression of a fractionated granite system that is prospective for tin, tantalum, niobium and lithium. Maiden drilling is scheduled for October 2026, the first systematic test of the historic system at depth. Triumph is an intrusion-related gold system near the historic Norton goldfield. It hosts an Inferred JORC 2012 Mineral Resource of 150koz at 2.1 g/t Au (ASX: DTM 4 Mar 2025) and a recently defined base case Exploration Target of 6.9Mt @ 2.29g/t gold for 506koz (ASX: DTM 11 Nov 2025). Mineralisation remains open at depth and along strike and drilling is planned to enhance the Mineral Resource and prioritise targets defined in the Exploration Target. The broader portfolio includes the Coonambula Antimony-Gold Joint Venture with Great Divide Mining (ASX: GDM), the McHargs tungsten prospect in northeast Victoria and the recently acquired Yamarna Gold Project in Western Australia. This gives Dart exposure to tin, tantalum, tungsten, antimony and gold. Dart manages the portfolio actively, advancing its highest-ranked targets and exploring value accretive deals on non-core assets. For more information, visit dartmining.com.au.