Average annual gold production of 273,000 ounces for 19-years, including peak average annual production of 316,000 ounces over the first five years, and a maximum annual production of 325,000 ounces in Year 15. 5.2 million ounces of gold production over the 19 years of conceptual mine life (“CML”). Base Case After-Tax NPV5% of C$1.36 billion (US$1.01 billion) and IRR of 13.4% at US$2,500/oz gold. Spot Price After-Tax NPV5% of C$3.30 billion (US$2.46 billion) and IRR of 24.0% at US$3,200/oz gold. 2025 MRE (as defined herein): 4.0 million ounces from 140.4 Mt grading 0.89 g/t Au in the Indicated category and 7.0 million ounces from 200.3 Mt grading 1.08 g/t Au in the Inferred category. 2025 PEA (as defined herein) is preliminary in nature and includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the 2025 PEA will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Toronto, Ontario–(Newsfile Corp. – May 15, 2025) – STLLR Gold Inc. (TSX: STLR) (OTCQX: STLRF) (FSE: O9D) (“STLLR” or the “Company“) announces the summary results of the updated Mineral Resource Estimate (“2025 MRE“) and updated Preliminary Economic Assessment (“2025 PEA“) for its 100%-owned Tower Gold Project (“Tower” or the “Project“) located in the prolific Timmins Mining Camp in Ontario, Canada. The 2025 MRE was prepared by InnovExplo (a member of Norda Stelo) and the 2025 PEA was compiled by G Mining Services (“GMS“). Table 1: 2025 PEA1 Economics* Potential Economics Gold Price Assumption US$2,500/oz Base Case US$3,200/oz Spot Pre-tax internal rate of return (“IRR“)(%) 16.1% 28.6% After-tax IRR 13.4% 24.0% Pre-tax net present value at 5% discount rate (“NPV5%“)(C$M) C$2,118 C$4,961 After-tax NPV5% (C$M) C$1,355 C$3,298 CML after-tax free cash flow (“FCF“)(C$M)2 C$3,438 C$6,739 FX rate assumption (USD/CAD) 1.34 1.34 After-tax NPV5%/Initial Capex ratio 0.7x 1.8x After-tax Payback period (years) 5.8 2.9 *Figures may vary slightly due to rounding Table 2: 2025 PEA1: Conceptual Mine Plan Summary* Metrics CML Total Per Unit Conceptual Mine Plan CML 19 years 2025 MRE conversion to conceptual mine plan 52% Total mineralized material (million tonnes “Mt“) 176.9 Mt 9.5 Mtpa3/26,030 tpd3 OP material during ramp-up 1.4 Mt OP 148.8 Mt 7.8Mtpa3/21,370 tpd3 UG 26.6 Mt 1.7Mtpa3/4,660 tpd3 Total OP waste rock mined (Mt) 652.7 Mt Total OP overburden tonnes (“OVB“) mined (Mt) 288.3 Mt Total OP waste (waste rock + OVB) 940.9 Mt Strip ratio, excluding OVB 4.3 Strip ratio, including OVB 6.3 Average mill gold head grade (“g/t Au“) 0.99 g/t Au CML OP production 0.75 g/t Au CML UG Production 2.35 g/t Au Average mill recovery rate (%) 92.7% Total potential payable gold production, excluding pre-production (thousand ounces “Koz“) 5,191 Koz 273 Koz/year Pre-production gold recovered, OP ramp-up 43 Koz OP production UG Production 3,326 Koz 1,868 Koz 175 Koz/year 98 Koz/year Capex and Opex Initial Capex (with contingency) (C$ millions “M“) C$1,873 M Pre-production revenue (C$M) C$144.6 M Sustaining Capex4 (excluding Closure/Salvage) C$1,723 M C$91 M/year Total Cash Costs5 C$8,901 M C$1,715/oz (US$1,280/oz) All-In Sustaining Cost (“AISC“)6 C$10,700 M C$2,059/oz (US$1,537/oz) All-In Costs (“AIC“)6 C$12,575 M C$2,403/oz (US$1,793/oz) *Figures may vary slightly due to rounding STLLR President and CEO Keyvan Salehi, P.Eng. commented: “Tower is one of Canada’s largest undeveloped gold projects, with size and scale matched only by a few Canadian gold projects. The 2025 PEA showcases the potential to produce 273,000 ounces of gold annually over 19 years, with peak production of 325,000 ounces. We believe the 2025 PEA delivers compelling economics with defensible capital and operating cost estimates. We designed the conceptual mine plan to maximize the output, which we believe is the best path to advance the Project and deliver long-term value. Furthermore, it is also our view that the geological environment hosting the Project continues along strike and at depth with solid upside potential for exploration. We believe this mine plan represents a strong foundation for a project with meaningful potential to grow in size, scale, and conceptual mine life.” “The 2025 MRE and 2025 PEA represent major advancements for Tower. We rebuilt the geological model from first principles, integrating detailed structural and lithological data to better represent the gold mineralization. Our disciplined approach has strengthened the 2025 MRE, increasing confidence and credibility, while laying the groundwork for more targeted and efficient future drilling. The Tower deposits remain open at depth and along strike to the west and east, with strong potential for expansion. In tandem, the mine plan was also developed using a comprehensive, bottom-up approach grounded in first principles, delivering a technically robust and executable strategy. Opportunities to grow the known mineralization, optimize the mine plan, and enhance project economics will continue to be pursued aggressively. Pre-Feasibility Study work is underway, with completion targeted for 2027. In parallel, we are advancing permitting efforts to potentially bring Tower to shovel-ready status by 2029. We believe Tower is one of a select group of large-scale gold projects in Ontario with a clear path to development in the foreseeable future.” Construction and Development Plan Located 100 km east of Timmins, Ontario, along Highway 101, the Project benefits from proximity to existing regional infrastructure, including paved highways, power distribution, and local supply chains. Its proximity to Timmins, Kirkland Lake, and Matheson, provides access to a skilled and experienced labour pool. The construction plan focuses initially on the development of the OP deposits, supported by the installation of key surface infrastructure, including a processing plant, tailings management facility (“TMF“), and other essential site services. The construction phase will be executed under an Integrated Project Management Team (“IPMT“) model over a 30-month period. Pre-production activities will begin in month 24, with first gold production expected during the subsequent 6-month commissioning and ramp-up phase. Stripping of overburden will commence at month 7, and OP mining operations will transition to a primarily owner-operated model upon the start of commercial production. Note that certain functions,