MONTREAL, Quebec — February 27, 2026 — Leads & Copy —
Brunswick Exploration Inc. (TSX-V: BRW, OTCQB: BRWXF; FRANKFURT:1XQ) has announced the filing of the “NI 43-101 Technical Report for the Mirage Maiden Mineral Resource Estimate, Eeyou Istchee James Bay, Quebec, Canada” on SEDAR, effective January 7, 2026.
The Mineral Resource Estimate (MRE) was prepared by PLR Resource Inc. and Synectiq Inc. in accordance with National Instrument (NI) 43-101 standards. The full technical report is accessible on SEDAR+ under Brunswick’s profile and on the company’s website.
Key results of the Maiden Mineral Resource Estimate were initially summarized in Brunswick’s press release on January 8, 2026.
According to Mr. Killian Charles, President and CEO of BRW, Brunswick Exploration is a compelling company in the lithium space, with advanced exploration in Quebec at both Mirage and Anatacau, along with a global grassroot exploration program.
Highlights of the report include an inferred resource of 52.2Mt at 1.08% Li2O and 131ppm Ta2O5 (see Table 1) at a cut-off grade of 0.5% Li2OEq for total contained lithia in excess of 550,000 tonnes, positioning Mirage among the largest undeveloped hard rock lithium resources in the Americas. An additional Exploration Target of 40Mt to 50Mt grading between 0.80% and 1.10% Li2O and 120ppm and 145ppm Ta2O5 indicates a significant opportunity for continued near-term growth at Mirage. The potential quantity and grade are conceptual and there has been insufficient exploration to define a mineral resource, and it is uncertain if further exploration will result in the target being delineated as a mineral resource.
The maiden resource and Exploration Target are confined to a core area measuring approximately 1.5 by 3.0 kilometers. There is substantial exploration potential across this area and further along strike, throughout the rest of the property where lithium mineralization is observed up to 3.5km from the MRE area.
Over 70% of the MRE is contained within five dykes found above a vertical depth of 150 meters from surface, all of which remain open in several directions. Metallurgical testwork demonstrates the potential for a dense media separation (DMS) only processing flowsheet, producing a high-quality concentrate.
The maiden MRE and Exploration Target were estimated after only 23,626 meters of drilling and 62 channel samples.
Table 1: Mirage Project Deposit In-pit Mineral Resource Estimate
The independent qualified persons for the MRE, as defined by National Instrument (“NI”) 43-101 guidelines, is Pierre Luc Richard, P.Geo., of PLR Resources Inc., with contributions from Patrick Frenette, P.Eng., of Synectiq Inc. for cut-off grade estimation and open pit optimization.
These Mineral Resources are not mineral reserves as they have no demonstrated economic viability. No economic evaluation of these Mineral Resources has been produced. The quantity and grade of reported Inferred Resources in this MRE are uncertain in nature and there has been insufficient drilling to define these Inferred Resources as Indicated. However, it is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated category with continued drilling.
The Qualified Persons are not aware of any known environmental, permitting, legal, title-related, taxation, socio-political, marketing or other relevant issues that could materially affect the Mineral Resource Estimate.
Calculations used metric units (metres, tonnes). Metal contents in the above table are presented in percentages, part per million (gram per tonne) and tonnes. Metric tonnage was rounded, and any discrepancies in total amounts are due to rounding errors.
CIM definitions and guidelines for Mineral Resource Estimates have been followed.
Resources are presented as undiluted and in situ for the open-pit scenario within 5m x 5m x 5m blocks. The constraining pit shell was developed using overall pit slopes of 53 degrees. The pit optimization to develop the mineral resource-constraining pit shell was done using the pseudoflow algorithm in Deswik software (see Figure 2).
The MRE wireframe was prepared using Leapfrog Edge v.2025.1.1 and is based on 132 drill holes and four trenches, totalling 23,626 meters and 8,288 assays. The cut-off date for the drill hole database was December 9, 2025.
Composites of one metre were created inside the mineralization domains. High-grade capping was done on the composited assay data. Depending on individual statistical study for each zone, composites were capped between 1.50% Li2O and 4.50% Li2O and between 200ppm Ta2O5 and 900ppm Ta2O5.
Pit constrained Mineral Resource for the base case is reported at a cut-off grade of 0.50% Li2OEq. The cut-off grades may be re-evaluated in the future based on prevailing market conditions and costs. A ratio Ta2O5 to Li2O of 0.00008658 (based on selling price, recoveries and other variables) was used to obtain the Li2OEq grade used in the cut-off.
Specific gravity values were estimated using data available in the drill hole database. Density values where interpolated when data was sufficient to do so, and completed with fixed values. Density values between 2.57 g/cm3 and 2.90 g/cm3 were applied to the model for different domains and 2.00 g/cm3 for overburden.
Grade model resource estimation was calculated from drill hole data using an Ordinary Kriging interpolation method in a sub-blocked model using blocks measuring 5m x 5m x 5m in size and sub-blocks down to 0.625m x 0.625m x 0.625m. Ordinary kriging (OK), inverse square distance (ID2), Nearest neighbour (NN) interpolation methods were tested, resulting in no material difference in the Mineral Resource Estimates.
The Inferred Mineral Resource categories are constrained to areas where drill spacing is less than 150 metres and show reasonable geological and grade continuity. Cookie cutters were used to define categories based on the above parameters.
Effective date of the Mineral Resource Estimate is 7 January 2026
The scientific and technical information contained in this press release has been reviewed and approved by Mr. Simon T. Hébert, VP Development. He is a Professional Geologist registered in Quebec and is a Qualified Person as defined by National Instrument 43-101. The independent qualified persons for the MRE, as defined by National Instrument (“NI”) 43-101 guidelines, is Pierre Luc Richard, P.Geo., of PLR Resources Inc., with contributions from Patrick Frenette, P.Eng., of Synectiq Inc. for cut-off grade estimation and open pit optimization, and from Jarrett Quinn, P.Eng., of Synectiq Inc. for metallurgical aspect.
Brunswick Exploration is a Montreal-based mineral exploration company listed on the TSX-V under symbol BRW. The Company is focused on grassroots exploration for lithium in Canada, a critical metal necessary to global decarbonization and energy transition. The company is rapidly advancing the most extensive grassroots lithium property portfolio in Canada, Greenland and Saudi Arabia underpinned by its Mirage project, one of the largest undeveloped hard-rock lithium Inferred Mineral Resource Estimate in the Americas, with 52.2Mt grading 1.08% Li2O.
Source: Brunswick Exploration Inc.
