Earnings release
Page 1
KCGM delivered solid quarter with cost discipline; Mill Expansion gathers strong momentum toward final build milestones Operating performance § SLTIFR1 at 0.6 injuries per million hours worked § Group underlying free cash flow of A$14 million and net mine cash flow of A$183 million § Gold sold totalled 381koz at an AISC of A$2,522/oz (US$1,639/oz)2 o KCGM underground achieved 2.9Mtpa annualised run rate; open pit productivity set to increase as Golden Pike North returned to one mining level o Thunderbox achieved record quarterly milled tonnes; lower grade stope ore at Jundee set to lift 2H o Pogo successfully developed two new portals for improved ore access and enhanced haulage efficiency FY26 outlook § FY26 production guidance of 1,700-1,850koz gold sold and AISC of A$2,300-2,700/oz § Operational disruptions at Jundee and South Kalgoorlie early in December quarter, estimated impact on 2Q gold sales of up to 20koz with affected volumes scheduled for processing over the remainder of FY26 § FY26 growth capital guidance of A$2,125-2,270 million (including KCGM Mill Expansion and Operational Readiness, and Hemi Development Project); FY26 exploration guidance of A$225 million § KCGM Mill Expansion in final build phase year and tracking to plan Investment-grade balance sheet; no hedge commitments added over the last year § Net cash3 of A$616 million; cash and bullion of A$1,511 million after A$416 million dividends paid and A$67 million in corporate tax instalments § Hedge commitments continue to unwind Commenting on the September quarter performance, Northern Star Managing Director Stuart Tonkin said: "The September quarter delivered a mixed performance across the portfolio. Our Kalgoorlie Production Centre performed well, led by KCGM, where we maintained elevated production and development rates. Overall, costs for the quarter were better than forecast reflecting our continued focus on capital discipline. "The KCGM Mill Expansion remains on track for early FY27 commissioning. This week, we received Ministerial approval for the Fimiston South Project and associated infrastructure, which supports higher future throughput and long-term cost efficiency at KCGM to deliver sustainable high-margin ounces. “We remain well positioned to deliver our full-year guidance, with stronger grades expected at KCGM in the second half along with improved volume and grade performance across the broader portfolio. Combined with growing leverage to gold prices and ongoing cost focus, we are firmly aligned to our purpose of delivering superior returns for our shareholders." Northern Star’s September quarterly conference call will be held today at 9:00am AEDT (6:00am AWST). The call can be accessed at: https://loghic.eventsair.com/579664/148223/Site/Register ASX: NST ASX Announcement 23 October 2025 QUARTERLY REPORT SEPTEMBER 2025 1 1 SLTIFR (12-month moving average) is defined as Serious Lost Time Injury Frequency Rate. 2 FYTD AUD:USD exchange rate is 0.65. 3 Net cash is defined as cash and bullion (A$1,511M) less corporate bank debt (A$0M) less Notes (A$895M = US$600M at AUD:USD rate of 0.66, less capitalised transactions costs). Cash is defined as cash and cash equivalents and term deposits. For personal use only
Page 2
OVERVIEW Northern Star Resources Ltd (ASX: NST) is pleased to report its operational and financial results for the September 2025 quarter, with gold sold of 381,055oz at an all-in sustaining cost (AISC) of A$2,522/oz. September quarter performance by production centre: § Kalgoorlie: 202,812oz gold sold at an AISC of A$2,474/oz § Yandal: 113,422oz gold sold at an AISC of A$2,778/oz § Pogo: 64,821oz gold sold at an AISC of US$1,453/oz All-in costs (AIC) of A$3,989/oz4 were higher than a year ago as capital growth projects continued across the Group, led by the KCGM Mill Expansion Project. Figure 1: Group Gold Sales and AISC koz A$/oz 208 197 222 203 132 121 137 113 71 68 85 65 2,128 2,246 2,197 2,522 Kalgoorlie Yandal Pogo AISC(A$/oz) Dec Q 2024 Mar Q 2025 Jun Q 2025 Sep Q 2025 0 100 200 300 400 500 600 0 400 800 1,200 1,600 2,000 2,400 2,800 FY26 Outlook Figure 2: FY26 Group guidance FY26 GUIDANCE UNITS KALGOORLIE YANDAL POGO TOTAL Gold Sold koz 930-1,000 500-550 270-300 1,700-1,850 AISC A$/oz 2,200-2,500 2,600-2,900 US$1,500-1,650(1) 2,300-2,700 Growth Capital Expenditure: Operational Growth Capital A$M 710-745 300-310 US$70-80 1,140-1,200(2) plus KCGM Mill Expansion Project A$M 530-550 - - 530-550 plus KCGM Mill Operational Readiness (3) A$M 315-370 315-370 plus Hemi Development Project A$M 140-150 Exploration A$M - - - ~225 (1) Pogo AISC and Capital Expenditure converted at a currency using AUD:USD = 0.64. (2) Total includes ~A$20M of corporate growth capital expenditure. (3) KCGM Mill Operational Readiness includes capital expenditure in relation to new tailing dam facilities, new thermal power station, maintenance equipment, tooling and initial stores stock and new accommodation camp. All items are associated with operating at its expanded throughput capacity of 27Mtpa from FY27. 2 4 Excludes Hemi development capital (A$41M), corporate growth capital (A$3M), Hemi exploration spend (A$5M) and exploration at other non-producing projects and regional sites (A$3M). For personal use only
Page 3
Production As announced on 7 July 2025, the Company has guided FY26 gold sold to be in the range of 1,700-1,850koz. Early in the December quarter, two separate events occurred at Jundee and South Kalgoorlie Operations. Both events are forecast to be resolved during the quarter, with an estimated impact on December quarter gold sales of up to 20koz. The affected volumes are scheduled for processing over the remainder of the year. KCGM is on track to deliver 550-600koz, with underground mined volumes at 3Mtpa, while open pit mining productivity is forecast to increase throughout the year as mining in Golden Pike North has now returned to one mining horizon. All-In Sustaining Costs FY26 AISC guidance is forecast to be in the range of A$2,300-2,700/oz. This reflects: § Inflationary pressures of ~5% across the global portfolio, corresponding to a year-on-year increase of ~A$100/oz; § Higher gold price related royalties and Pogo tariff assumptions have also contributed (~A$40/oz); § Sustaining capital of ~A$750 million, corresponding to ~A$420/oz or a year-on-year increase of ~A$130/oz primarily from: o Higher development advance and associated underground ventilation, power and pumping infrastructure investment across underground operations (Kal Ops, KCGM, Jundee, Pogo); o Processing plant capital across all facilities to underpin asset availability and reliability; o Additional lease payments for open pit fleet at Yandal and underground fleet at Pogo, and haul truck fleet mid-life rebuilds at KCGM; and o Allocation of mining operating and development costs, including deferred stripping to all-in sustaining costs (operating and sustaining capital) for assets expected to reach commercial production during FY26. These include Griffin underground at Jundee, Wonder underground at TBO, and Bannockburn and Orelia open pit operations at Yandal. Growth Capital Expenditure Northern Star continues to advance major growth projects to achieve its goal of being a long-life, high margin, returns-focused global gold producer (bottom half of the global cost curve). The KCGM Mill Expansion and Hemi Development Project are forecast to be the key enablers to achieving this goal. FY26 Group growth capital expenditure includes Operational Growth Capital, KCGM Mill Expansion Project, KCGM Mill Operational Readiness and the Hemi Development Project - as shown in Figure 2. KCGM's growth capital expenditure in FY26 consists of several projects associated with its readiness to operate at its expanded throughput capacity of 27Mtpa from FY27 and to further unlock future value. A breakdown of KCGM's growth capital is: § KCGM Mill Expansion Project: A$530-550 million, unchanged from previous guidance. The project is in the final year of the build phase to enable first production early FY27. § KCGM Operational Development: A$500-550 million for open pit material movement (Fimiston South cutback) and underground development activities (Fimiston Underground and Mt Charlotte) to enable future high-grade ore feed for the plant. § KCGM Mill Operational Readiness of A$315-370 million including: o KCGM tailings dam facilities: A$180-220 million for new tailings dam facilities with additional spend of A$180-220 million required in FY27 to complete construction. This expenditure has been brought forward by 3-5 years due to the increased throughput rate of the expanded mill. Environmental approval for the Fimiston South Project including the new tailings dam was received on 20 October. Early works have since commenced. o KCGM thermal power plant and transmission infrastructure: A$85 million in FY26 and A$70 million in FY27 for a new, purpose-built thermal power station with renewable ready transmission infrastructure (50% joint venture). The thermal power station is the preferred solution for long-term future power requirements as it is more efficient in economics, emissions, multi-fuel sources and energy responsiveness. Following commissioning of the new thermal power station, the existing Parkeston Power Station will still be capable of playing a substantial role in the energy market or to third-party customers. 3 For personal use only
Page 4
o KCGM accommodation camp: A$30-35 million in FY26 for a permanent on-site facility, 100% owned by Northern Star and to be used for future projects and shutdowns. o KCGM operational growth capital of A$20-30 million in FY26 for commissioning and initial stores consumables. FY26 growth capital expenditure at Yandal is forecast to be in the range of A$300-310 million, with A$220 million for the Thunderbox Operations. This primarily relates to open pit development (including pre-stripping), infrastructure, and required equipment for Bannockburn and the Orelia Stage 2 cutback. This underpins future mill feed to operate at 6Mtpa capacity. FY26 growth capital expenditure at Pogo is forecast to be in the range of US$70-80 million for underground development and infrastructure associated with increasing mining volumes, along with accessing new areas; and further mill optimisation works focusing on throughput and recovery. At the Hemi Development Project, A$140-150 million planned spend includes ongoing engineering and design, as well as commitments for long lead time items (as agreed by previous owners). Northern Star continues to work closely with State and Federal regulators, key stakeholders and the broader Pilbara community. Exploration Exploration expenditure in FY26 is forecast to be approximately A$225 million, including the Hemi regional exploration. 4 For personal use only
Page 5
KCGM Mill Expansion Project - Kalgoorlie, Western Australia The KCGM Mill Expansion Project, centred on the Fimiston Processing Plant, will replace 85% of the 13Mtpa plant, increasing the overall processing capacity to 27Mtpa and then consolidate the Gidji facility. KCGM is expected to operate at ~900kozpa from FY29 (steady state), following a two-year ramp-up (FY27-28) upon completion of the Mill Expansion. Financial Overview: Cash flow generation from the existing operation will continue during FY26 with cut-over remaining on track for early FY27 ramp-up. Capital expenditure during the September quarter was A$196 million, bringing total project spend to date (from 1Q FY24) to A$1,096 million. Forecast FY26 capital expenditure remains unchanged at A$530-550 million. Construction Update: During the September quarter, the project significantly advanced structural and mechanical installation, and transitioned to electrical and piping installation. Key achievements include: § All switch rooms installed § 75% of structural steel erected with 50% of mechanical installation completed § Commenced electrical cabling and piping For the remainder of FY26, the project will transition into the final stages of construction, progressing through finishing works, fit-outs, and commissioning and testing. Figure 3: Installation of SAG and Ball Mills (image left) and Tailings Pipelines (image right) Figure 4: KCGM Mill Expansion Project Progress 5 For personal use only
Page 6
Table 1: September quarter 2026 performance summary - by production centre 3 MONTHS ENDING SEP 2025 Units Kalgoorlie Yandal Pogo (6) Total Underground Mining Ore Mined Tonnes 1,728,005 1,492,026 353,305 3,573,336 Mined Grade g/t Au 2.3 2.2 6.5 2.7 Ounces Mined oz 126,434 105,270 73,752 305,456 Open Pit Mining Open Pit Material Moved BCM 9,805,165 4,692,515 — 14,497,680 Open Pit Ore Mined Tonnes 2,832,822 921,749 — 3,754,571 Mined Grade g/t Au 1.2 0.9 — 1.1 Ounces Mined oz 112,271 25,226 — 137,497 Milled Tonnes Tonnes 4,351,526 2,470,670 359,823 7,182,019 Head Grade g/t Au 1.7 1.7 6.5 1.9 Recovery % 86 86 87 86 Gold Recovered oz 204,419 113,046 65,208 382,673 Gold Sold oz 202,812 113,422 64,821 381,055 Average Price A$/oz 4,445 4,478 4,429 4,452 Revenue - Gold A$M 902 508 287 1,697 Total Stockpiles Contained Gold oz 3,697,858 232,526 1,002 3,931,386 Gold in Circuit (GIC) oz 44,203 10,087 4,726 59,016 Gold in Transit oz 500 — — 500 Total Gold Inventories oz 3,742,561 242,613 5,728 3,990,902 Underground Mining A$M 146 142 76 364 Open Pit Mining A$M 89 28 — 117 Processing A$M 166 70 38 274 Site Services A$M 20 15 15 50 Ore Stock & GIC Movements A$M (70) (13) (3) (86) Royalties A$M 37 20 — 57 By-Product Credits A$M (4) (1) — (5) Cash Operating Cost A$M 384 261 126 771 Rehabilitation A$M 7 3 1 11 Corporate Overheads (2) A$M 22 12 4 38 Sustaining Capital (4) A$M 90 40 14 144 All-in Sustaining Cost A$M 503 316 145 964 Exploration (3) A$M 18 13 14 45 Growth Capital (4)(5) A$M 393 95 25 513 All-in Costs A$M 914 424 184 1,522 Mine Operating Cash Flow (1) A$M 358 194 144 696 Net Mine Cash Flow (1) A$M (35) 99 119 183 Cash Operating Cost A$/oz 1,889 2,290 1,937 2,017 All-in Sustaining Cost A$/oz 2,474 2,778 2,222 2,522 All-in Costs (4)(5) A$/oz 4,504 3,732 2,829 3,989 Depreciation & Amortisation A$/oz 987 874 622 897 Non - Cash Inventory Movements A$/oz (132) (63) 3 (88) (1) Mine Operating Cash Flow is calculated as Revenue, less Cash Operating Costs (excluding inventory movements) and Sustaining Capital. Net Mine Cash Flow is calculated as Mine Operating Cash Flow less Growth Capital. (2) Includes the non-cash share based payment expenses in corporate overheads. (3) Excludes Hemi exploration spend (A$5M) and other non-producing projects and regional sites (A$3M). (4) A$46M of lease repayments are included in Sustaining Capex (A$144M) and A$21M in Growth Capex (A$513M). Lease repayments are included in cash flows from financing activities in the Consolidated Statement of Cash Flows included in the Company’s financial statements. (5) Excludes Hemi development capital (A$41M) and corporate growth capital (A$3M). (6) Pogo Operations costs are presented in AUD which is the Group’s reporting currency. USD cost disclosure is presented in Table 10. FYTD AUD:USD exchange rate is 0.65. 6 For personal use only
Page 7
OPERATIONS Safety Performance Northern Star prioritises the safety and wellbeing of our people. Safety is a Core Value and our commitment is consistently reflected in our strong safety performance. The end-of-quarter Serious Lost Time Injury Frequency Rate (SLTIFR) was 0.6 injuries per million hours worked. Table 2: September 2025 Group safety performance (12-month moving average) Term Kalgoorlie Yandal Pogo Group SIFR 3.6 2.9 0.0 2.8 SLTIFR 0.6 0.7 0.0 0.6 Kalgoorlie Production Centre (KCGM, Carosue Dam, Kalgoorlie Operations) Kalgoorlie sold 203koz at an AISC of A$2,474/oz, compared with the performance in the June quarter of 222koz at an AISC of A$2,234/oz. Mine operating cash flow was A$358 million. Net mine cash flow was an outflow of A$35 million after growth capital of A$393 million. KCGM sold 103koz at an AISC of A$2,503/oz, compared with the June quarter of 118koz at an AISC of A$2,237/oz. Mine operating cash flow was A$153 million. Net mine cash flow was an outflow of A$227 million after growth capital of A$380 million. At KCGM, open pit mining activities focused on ore sources at Oroya Brownhill and Golden Pike North, with material movement at Fimiston South. Open pit ore mined and grade was in line with expectations, and higher than a year ago. Total open pit material movement was 22.5Mt during the September quarter, in line with the previous quarter, with a continued focus on increasing productivity. Underground ore mined volumes were 735kt, corresponding to an annualised run rate of 2.9Mtpa, with lower mined grades attributed to the step up in development rates. Northern Star Mining Services (NSMS) increased development metres to 8.7km for the quarter (vs June quarter: 7.5km). KCGM milled tonnes delivered an annualised run rate of 11.6Mtpa, notwithstanding a major planned shutdown during the quarter. For FY26, milled throughput is forecast to be 12Mtpa with milled grades forecast to lift for the remainder of the year. At Carosue Dam, gold sold totalled 57koz at an all-in cost (AIC) of A$2,594/oz, the lowest of the Group. Ore was sourced from the Karari, Whirling Dervish and Porphyry underground operations, in addition to Wallbrook open pit. At the Kalgoorlie Operations, gold sales normalised to 43koz for the September quarter driven by grade. In early October, a wall slip occurred in the historic open pit at South Kalgoorlie, temporarily affecting infrastructure for the underground mine. The main portal to the underground operations remains unaffected. A return to normal stope mining is expected during the quarter. The estimated impact on December quarter gold sales is up to 10koz. Figure 5: Kalgoorlie Production Centre - Gold Sales and AISC koz A$/oz Gold Sales (koz) AISC (A$/oz) Dec Q 2024 Mar Q 2025 Jun Q 2025 Sep Q 2025 0 50 100 150 200 250 0 400 800 1,200 1,600 2,000 2,400 2,800 7 For personal use only
Page 8
Yandal Production Centre (Jundee, Thunderbox, Bronzewing) Yandal sold 113koz at an AISC of A$2,778/oz, compared with the performance in the June quarter of 137koz at an AISC of A$2,383/oz. Mine operating cash flow was A$194 million. Net mine cash flow was A$99 million after growth capital of A$95 million. At Jundee, strong milling performance partially offset lower grade stope ore at Jundee and Ramone, which also impacted recovery. Similar grades are expected to continue during the December quarter, before increasing in the second half. Development at Griffin progressed ahead of schedule with first ore commencing in 2Q FY26 (previously 2H FY26), enabling future access to high grade stope tonnes. In early October, a localised structural failure occurred in the crushing circuit. The conveyor has been reconfigured to the SAG mill, enabling operations to resume within two weeks. The estimated impact on December quarter gold sales is up to 10koz. At Thunderbox, milling throughput achieved a record annualised run rate of 6.7Mtpa, exceeding the nameplate capacity of 6Mtpa for a second consecutive quarter. This strong milling performance was a highlight and offset lower milled grades from Orelia open pit, which are expected to increase in the second half, along with underground volumes. Mining activities focused on high grade ore from Thunderbox and Wonder underground mines, while open pit ore continued to be sourced from Orelia. At Bannockburn, open pit mining ramped up significantly, with first ore expected to feed the mill in 2H FY26. Figure 6: Yandal Production Centre - Gold Sales and AISC koz A$/oz Gold Sales (koz) AISC (A$/oz) Dec Q 2024 Mar Q 2025 Jun Q 2025 Sep Q 2025 0 30 60 90 120 150 0 400 800 1,200 1,600 2,000 2,400 2,800 Pogo Production Centre Pogo sold 65koz at an AISC of US$1,453/oz, compared with the performance in the June quarter of 85koz at an AISC of US$1,154/oz. Mine operating cash flow was US$95 million. Net mine cash flow was US$78 million after growth capital of US$17 million. The Pogo underground mine and mill operated at an annualised run rate of 1.4Mtpa during the September quarter, despite a planned major mill shutdown. While mined grade was affected by mine sequencing, grade is expected to improve over the remainder of the year. The mill remains focused on optimising recovery through a series of improvement initiatives, achieving a recovery rate of 87% despite the lower head grade. Mine development progressed achieving an average rate of 1,664 metres per month. Development of two new portals continued, providing access to the Central Veins and Goodpaster systems, with most supporting infrastructure nearing completion. These portals are also expected to enhance ventilation and haulage efficiency across other areas of the mine. The mine delivered 216kt of stope ore, corresponding to 61% of the total ore mined. 8 For personal use only
Page 9
Figure 7: Pogo Production Centre - Gold Sales and AISC Koz US$/oz Gold Sales (koz) AISC (US$/oz) Dec Q 2024 Mar Q 2025 Jun Q 2025 Sep Q 2025 0 20 40 60 80 0 400 800 1,200 1,600 2,000 Refer to Appendix 1 for additional operating and costs statistics on the individual operations. DISCOVERY AND GROWTH For the September quarter, A$54 million was invested in exploration (FY26 guidance: A$225 million) as focus continues on significant life-of-mine extensions and in-mine growth. FINANCE For the September quarter, the average gold sales price realised by Northern Star was A$4,452/oz to generate gold sales revenue of A$1,697 million. The September quarter non-cash inventory movement was a credit of A$34 million. Non-cash inventory movement is used for the reconciliation of AISC to EBITDA in the Profit and Loss statement. Cash(1) and Bullion At 30 September, cash(1) and bullion totalled A$1,511 million. Table 3: Cash(1) and bullion Dec Q 2024 Mar Q 2025 Jun Q 2025 Sep Q 2025 Cash(1) A$M $1,046 $955 $1,690 $1,258 Bullion(2) A$M $169 $166 $224 $253 Total A$M $1,215 $1,121 $1,914 $1,511 (1) Cash is defined as cash and cash equivalents and term deposits. (2) Bullion includes dore which has been received by the refiner or collected by a third-party transport provider in the quarter and sold and is awaiting settlement. The waterfall chart (Figure 8) highlights the September quarter movements in cash(1) and bullion (A$M). Underlying free cash flow from operations was A$14 million. This includes A$64 million of equipment finance/leases and A$67 million in corporate tax instalments. 9 For personal use only
Page 10
Figure 8: September quarter 2026 cash and bullion movements 1,914 818 (67) (614) (59) 1,992 (64) (416) (1) 1,511 Opening Operating cashflow Income tax paid PP&E + Mine Properties Exploration Closing before M&A and Financing Equipment Finance/Leases Dividend Others (inc: FX) Closing Banking Facilities Northern Star holds corporate bank facilities with maturity dates of December 2027 and December 2028 across two equal tranches totalling A$1,500 million. The facilities remain undrawn and available at quarter end. The Company also has US$600 million senior guaranteed notes (“Notes”). The Notes, due in April 2033, are guaranteed by certain wholly owned subsidiaries of Northern Star with interest payable semi-annually at a rate of 6.125% per annum. Hedging The Company has updated its hedging policy and has removed mandatory hedge commitments. This enables the continued wind down of the hedge book. No hedge commitments have been added over the last four quarters. During the quarter, no hedges were added while 158koz of hedges were delivered at A$3,105/oz. Total hedging commitments as at 30 September comprised 1.275Moz at an average price of A$3,309/oz. Table 4: Hedging commitments at 30 September 2025 Term Dec H 25 Jun H 26 Dec H 26 Jun H 27 Dec H 27 Jun H 28 Total Ounces (oz) 157,500 330,000 280,000 237,500 180,000 90,000 1,275,000 Gold Price (A$/oz) 3,132 3,181 3,292 3,340 3,532 3,603 3,309 De Grey integration Northern Star provides the following financial information. Permitting: The final investment decision for Hemi is subject to securing final permitting and approvals. Northern Star will continue to advance the State and Federal permitting process as well as work closely with all the Traditional Owners in the management of Native Title and Aboriginal Heritage. Tax: Northern Star has ascribed tax values to De Grey’s assets based on the consideration value. Northern Star has also elected to transfer a portion of De Grey’s previously incurred tax losses. Collectively, tax depreciation and tax losses will reduce Northern Star’s future taxable income and therefore income tax payments. Tax depreciation commenced from the Implementation Date, and Northern Star expects to amortise approximately 50% of the tax depreciable value within five years. Transaction Costs (Including Duty): The current estimate of the transaction costs (including landholder duty) associated with the acquisition of De Grey is estimated to be in the range of $200-250 million, subject to asset value classification and determination for landholder duty purposes. Northern Star expects an interim assessment within 12-24 months of implementation being 5 May 2025. Profit and Loss Depreciation: Depreciation and amortisation will commence once commercial production is achieved and ore extraction is underway. 10 For personal use only
Page 11
CORPORATE On 21 August, Northern Star released its FY25 Annual Reporting Suite including the Annual Report, Environment & Social Responsibility Disclosures, Corporate Governance Statement and Modern Slavery Statement. On 25 September, Northern Star paid the FY25 final dividend of A$0.30 per share. On 30 September, the Company released its Notice of Annual General Meeting. The AGM will be held as a hybrid event at 1:30pm AWST on Tuesday, 18 November 2025. The issued capital of the Company at the date of this Report comprises: § Ordinary Fully Paid Shares (NST): 1,430,735,312 § Performance & Conditional Retention Rights (NSTAA): 10,796,149 § NED Share Rights (NSTAC): 8,488 This announcement is authorised for release to the ASX by Stuart Tonkin, Managing Director & CEO. Investor Relations: Sophie Spartalis Northern Star Resources Ltd T: +61 8 6489 2488 E: investorrelations@nsrltd.com Media Enquiries: Peter Klinger Purple T: +61 411 251 540 E: pklinger@purple.au Forward Looking Statements Northern Star Resources Ltd 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 and conclusions contained in this announcement. To the maximum extent permitted by law, none of Northern Star Resources Ltd, its directors, employees or agents, advisers, 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. This announcement may contain forward looking statements that are subject to risk factors associated with gold exploration, mining and production businesses. It is believed that the expectations reflected in these statements are reasonable but they may be affected by a variety of variables and changes in underlying assumptions which could cause actual results or trends to differ materially, including but not limited to price fluctuations, actual demand, currency fluctuations, drilling and production results, Resource or Reserve estimations, loss of market, industry competition, environmental risks, physical risks, legislative, fiscal and regulatory changes, economic and financial market conditions in various countries and regions, political risks, project delay or advancement, approvals and cost estimates. ASX Listing Rules Disclosures The information in this announcement that relates to the current Ore Reserves and Mineral Resources of Northern Star has been extracted from the ASX release by Northern Star entitled “Resources, Reserves and Exploration Update” dated 15 May 2025 available at www.nsrltd.com and www.asx.com (“Northern Star Announcement”). Northern Star confirms that it is not aware of any new information or data that materially affects the information included in the Northern Star Announcement other than changes due to normal mining depletion during the seven month period to 22 October 2025, and, in relation to the estimates of Northern Star's Ore Reserves and Mineral Resources, that all material assumptions and technical parameters underpinning the estimates in the Northern Star Announcement continue to apply and have not materially changed. Northern Star confirms that the form and context in which the Competent Person's findings are presented have not been materially modified from that announcement. Currency Conversion Rate Unless stated otherwise, all currency conversions for the September quarter have been converted at a currency of AUD:USD exchange rate of 0.65. 11 For personal use only
Page 12
APPENDIX 1 - ADDITIONAL INFORMATION - OPERATIONS KCGM Operations Table 5: Summary Details - KCGM Operations Ore Mined - Underground Tonnes 469,804 490,453 870,638 734,729 734,729 Mined Grade g/t Au 1.8 1.6 1.8 1.6 1.6 Ounces Mined - Underground Oz 27,859 26,007 49,437 37,608 37,608 Open Pit Material Moved BCM 6,108,217 5,937,877 8,895,993 8,528,577 8,528,577 Ore Mined - Open Pit Tonnes 1,051,966 2,174,396 3,207,070 2,337,394 2,337,394 Mined Grade g/t Au 1.2 1.2 1.1 1.2 1.2 Ounces Mined - Open Pit Oz 39,251 84,228 114,680 93,098 93,098 Total Mined Ounces Oz 67,110 110,235 164,117 130,706 130,706 Milled Tonnes Tonnes 3,104,253 2,843,374 3,178,050 2,902,614 2,902,614 Head Grade g/t Au 1.3 1.3 1.4 1.4 1.4 Recovery % 78 82 80 83 83 Gold Recovered Oz 98,305 99,998 117,367 107,118 107,118 Gold Sold Oz 99,787 96,122 118,097 103,139 103,139 Cost per Ounce Underground Mining A$/oz 210 179 321 399 399 Open Pit Mining A$/oz 337 684 742 654 654 Processing A$/oz 881 1,000 1,098 1,143 1,143 Site Services A$/oz 82 88 77 84 84 Ore Stock & GIC Movements A$/oz (201) (607) (625) (594) (594) Royalties A$/oz 128 149 155 193 193 By-Product Credits A$/oz (16) (11) (12) (19) (19) Cash Operating Costs A$/oz 1,421 1,482 1,756 1,860 1,860 Rehabilitation - Accretion & Amortisation A$/oz 31 33 26 41 41 Corporate Overheads A$/oz 84 68 52 111 111 Mine Development / Sustaining CAPEX A$/oz 343 580 403 491 491 All-in Sustaining Costs A$/oz 1,879 2,163 2,237 2,503 2,503 Exploration A$/oz 189 139 119 119 119 Growth Capital A$/oz 2,935 2,484 2,642 3,686 3,686 All-in Costs A$/oz 5,003 4,786 4,998 6,308 6,308 Depreciation & Amortisation A$/oz 590 873 914 856 856 Non-Cash Ore Stock & GIC Movements A$/oz (40) (235) (236) (215) (215) Production Summary Units Dec-24 Qtr Mar-25 Qtr Jun-25 Qtr Sep-25 Qtr FYTD 12 For personal use only
Page 13
Carosue Dam Operations Table 6: Summary Details - Carosue Dam Operations Production Summary Units Dec-24 Qtr Mar-25 Qtr Jun-25 Qtr Sep-25 Qtr FYTD Ore Mined - Underground Tonnes 573,119 556,189 556,095 537,469 537,469 Mined Grade g/t Au 2.9 2.5 2.6 2.5 2.5 Ounces Mined - Underground Oz 53,421 44,796 45,774 42,911 42,911 Open Pit Material Moved BCM 1,212,749 1,157,790 1,292,849 886,245 886,245 Ore Mined - Open Pit Tonnes 378,507 535,116 778,751 495,428 495,428 Mined Grade g/t Au 1.0 1.2 1.1 1.2 1.2 Ounces Mined - Open Pit Oz 11,905 20,243 27,856 19,173 19,173 Total Mined Ounces Oz 65,326 65,039 73,630 62,084 62,084 Milled Tonnes Tonnes 1,014,204 965,375 986,958 994,240 994,240 Head Grade g/t Au 2.3 2.0 2.0 1.9 1.9 Recovery % 91 91 92 92 92 Gold Recovered Oz 67,298 56,174 59,470 56,505 56,505 Gold Sold Oz 66,522 57,661 58,464 56,934 56,934 Cost per Ounce Underground Mining A$/oz 914 1,037 995 995 995 Open Pit Mining A$/oz 168 233 402 374 374 Processing A$/oz 368 440 456 445 445 Site Services A$/oz 101 101 113 117 117 Ore Stock & GIC Movements A$/oz 48 (8) (164) (110) (110) Royalties A$/oz 159 183 202 210 210 By-Product Credits A$/oz (4) (7) (11) (18) (18) Cash Operating Costs A$/oz 1,754 1,979 1,993 2,013 2,013 Rehabilitation - Accretion & Amortisation A$/oz 21 22 22 18 18 Corporate Overheads A$/oz 84 67 50 112 112 Mine Development / Sustaining CAPEX A$/oz 247 217 282 394 394 All-in Sustaining Costs A$/oz 2,106 2,285 2,347 2,537 2,537 Exploration A$/oz 24 15 27 22 22 Growth Capital A$/oz 37 124 99 35 35 All-in Costs A$/oz 2,167 2,424 2,473 2,594 2,594 Depreciation & Amortisation A$/oz 1,329 1,340 1,539 1,546 1,546 Non-Cash Ore Stock & GIC Movements A$/oz (6) (86) (269) (85) (85) 13 For personal use only
Page 14
Kalgoorlie Operations Table 7: Summary Details - Kalgoorlie Operations Production Summary Units Dec-24 Qtr Mar-25 Qtr Jun-25 Qtr Sep-25 Qtr FYTD Ore Mined Tonnes 480,782 491,486 430,669 455,807 455,807 Mined Grade g/t Au 3.1 3.0 3.7 3.1 3.1 Ounces Mined Oz 47,923 46,900 51,819 45,915 45,915 Milled Tonnes Tonnes 503,897 496,116 465,380 454,672 454,672 Head Grade g/t Au 2.8 3.3 3.8 3.2 3.2 Recovery % 88 88 90 87 87 Gold Recovered Oz 40,512 46,092 51,788 40,796 40,796 Gold Sold Oz 41,726 42,840 45,675 42,739 42,739 Cost per Ounce Mining A$/oz 1,095 1,023 1,060 1,119 1,119 Processing A$/oz 525 426 555 521 521 Site Services A$/oz 99 112 120 113 113 Ore Stock & GIC Movements A$/oz 48 (37) (214) (58) (58) Royalties A$/oz 89 75 119 119 119 By-Product Credits A$/oz (15) (13) (11) (13) (13) Cash Operating Costs A$/oz 1,841 1,586 1,629 1,801 1,801 Rehabilitation - Accretion & Amortisation A$/oz 42 37 36 32 32 Corporate Overheads A$/oz 85 68 43 105 105 Mine Development / Sustaining CAPEX A$/oz 249 201 371 391 391 All-in Sustaining Costs A$/oz 2,217 1,892 2,079 2,329 2,329 Exploration A$/oz 265 223 265 114 114 Growth Capital A$/oz 291 367 322 261 261 All-in Costs A$/oz 2,773 2,482 2,666 2,704 2,704 Depreciation & Amortisation A$/oz 375 440 454 453 453 Non-Cash Ore Stock & GIC Movements A$/oz 19 (28) (46) 7 7 14 For personal use only
Page 15
Jundee Operations Table 8: Summary Details - Jundee Operations Production Summary Units Dec-24 Qtr Mar-25 Qtr Jun-25 Qtr Sep-25 Qtr FYTD Ore Mined - Underground Tonnes 605,184 688,874 759,728 787,545 787,545 Mined Grade g/t Au 3.4 3.2 3.1 2.5 2.5 Ounces Mined - Underground Oz 65,832 71,293 75,550 64,054 64,054 Open Pit Material Moved BCM — — — — — Ore Mined - Open Pit Tonnes — — — — — Mined Grade g/t Au — — — — — Ounces Mined - Open Pit Oz — — — — — Total Mined Ounces Oz 65,832 71,293 75,550 64,054 64,054 Milled Tonnes Tonnes 731,383 743,965 838,004 785,866 785,866 Head Grade g/t Au 3.4 3.0 3.0 2.6 2.6 Recovery % 91 88 87 84 84 Gold Recovered Oz 72,357 64,373 70,849 54,735 54,735 Gold Sold Oz 73,600 64,530 75,490 54,537 54,537 Cost per Ounce Underground Mining A$/oz 843 1,040 1,014 1,524 1,524 Processing A$/oz 337 432 378 554 554 Site Services A$/oz 93 108 96 124 124 Ore Stock & GIC Movements A$/oz 144 1 90 (221) (221) Royalties A$/oz 129 144 179 171 171 By-Product Credits A$/oz (6) (8) (6) (7) (7) Cash Operating Costs A$/oz 1,540 1,717 1,751 2,145 2,145 Rehabilitation - Accretion & Amortisation A$/oz 19 21 18 28 28 Corporate Overheads A$/oz 80 68 49 107 107 Mine Development / Sustaining CAPEX A$/oz 259 393 332 407 407 All-in Sustaining Costs A$/oz 1,898 2,199 2,150 2,687 2,687 Exploration A$/oz 218 193 152 126 126 Growth Capital A$/oz 528 559 468 433 433 All-in Costs A$/oz 2,644 2,951 2,770 3,246 3,246 Depreciation & Amortisation A$/oz 337 375 351 412 412 Non-Cash Ore Stock & GIC Movements A$/oz 96 26 40 71 71 15 For personal use only
Page 16
Thunderbox & Bronzewing Operations Table 9: Summary Details - Thunderbox & Bronzewing Operations Production Summary Units Dec-24 Qtr Mar-25 Qtr Jun-25 Qtr Sep-25 Qtr FYTD Ore Mined - Underground Tonnes 656,804 580,317 808,040 704,481 704,481 Mined Grade g/t Au 1.7 1.7 1.8 1.8 1.8 Ounces Mined - Underground Oz 35,145 30,880 45,882 41,216 41,216 Open Pit Material Moved BCM 2,736,505 3,245,653 4,520,325 4,692,515 4,692,515 Ore Mined - Open Pit Tonnes 1,528,400 968,873 1,007,892 921,749 921,749 Mined Grade g/t Au 1.0 1.1 0.9 0.9 0.9 Ounces Mined - Open Pit Oz 47,134 34,094 30,711 25,226 25,226 Total Mined Ounces Oz 82,279 64,974 76,593 66,442 66,442 Milled Tonnes Tonnes 1,462,710 1,427,907 1,584,063 1,684,804 1,684,804 Head Grade g/t Au 1.4 1.4 1.4 1.2 1.2 Recovery % 89 86 89 88 88 Gold Recovered Oz 59,065 54,207 62,095 58,311 58,311 Gold Sold Oz 58,017 56,234 61,183 58,885 58,885 Cost per Ounce Underground Mining A$/oz 715 784 963 1,003 1,003 Open Pit Mining A$/oz 716 442 518 471 471 Processing A$/oz 771 657 716 669 669 Site Services A$/oz 112 138 108 134 134 Ore Stock & GIC Movements A$/oz (229) 70 (99) (21) (21) Royalties A$/oz 113 145 161 185 185 By-Product Credits A$/oz (7) (9) (9) (16) (16) Cash Operating Cost A$/oz 2,191 2,227 2,358 2,425 2,425 Rehabilitation - Accretion & Amortisation A$/oz 23 24 22 33 33 Corporate Overheads A$/oz 79 71 49 107 107 Mine Development / Sustaining CAPEX A$/oz 416 304 244 297 297 All-in Sustaining Costs A$/oz 2,709 2,626 2,673 2,862 2,862 Exploration A$/oz 97 106 115 108 108 Growth Capital A$/oz 735 982 1,001 1,213 1,213 All-in Costs A$/oz 3,541 3,714 3,789 4,183 4,183 Depreciation & Amortisation A$/oz 1,893 1,444 1,568 1,301 1,301 Non-Cash Ore Stock & GIC Movements A$/oz (753) (311) (507) (186) (186) 16 For personal use only
Page 17
Pogo Operations Table 10: Summary Details - Pogo Operations (US$)(2) Production Summary Units Dec-24 Qtr Mar-25 Qtr Jun-25 Qtr Sep-25 Qtr FYTD Ore Mined Tonnes 313,972 329,108 393,403 353,305 353,305 Mined Grade g/t Au 7.6 7.3 7.6 6.5 6.5 Ounces Mined Oz 76,995 77,134 96,530 73,752 73,752 Milled Tonnes Tonnes 364,468 338,579 394,407 359,823 359,823 Head Grade g/t Au 7.4 7.3 7.7 6.5 6.5 Recovery % 84 85 87 87 87 Gold Recovered Oz 72,786 67,516 84,339 65,208 65,208 Gold Sold Oz 70,597 68,054 85,125 64,821 64,821 Cost per Ounce Mining US$/oz 710 715 606 765 765 Processing US$/oz 360 379 300 382 382 Site Services US$/oz 117 113 106 155 155 Ore Stock & GIC Movements US$/oz 54 48 31 (32) (32) By-Product Credits US$/oz (2) (4) (2) (4) (4) Cash Operating Costs US$/oz 1,239 1,251 1,041 1,266 1,266 Rehabilitation - Accretion & Amortisation US$/oz 25 7 6 8 8 Corporate Overheads(1) US$/oz 29 23 15 39 39 Mine Development / Sustaining CAPEX US$/oz 157 158 92 140 140 All-in Sustaining Costs US$/oz 1,450 1,439 1,154 1,453 1,453 Exploration US$/oz 91 121 112 141 141 Growth Capital US$/oz 178 185 170 256 256 All-in Costs US$/oz 1,719 1,745 1,436 1,850 1,850 Depreciation & Amortisation US$/oz 336 406 395 407 407 Non-Cash Ore Stock & GIC Movements US$/oz 22 3 9 2 2 (1) Corporate costs are allocated to Pogo based on services provided. The remaining amount is allocated to the Australian Operations based on gold sold (production ounces). (2) Pogo Operations costs are presented in USD which is the functional currency of the operation. The figures are presented in AUD in Table 1 above, which is the Group's presentational currency. The September quarter AUD:USD exchange rate is 0.65 and FYTD AUD:USD exchange rate is 0.65 respectively. 17 For personal use only