Grande Portage Resources Increases Ounces and Grade in an Updated Mineral Resource Estimate for the Herbert Gold Deposit in SE Alaska.---1,438,500 Indicated (9.47gpt) and 515,700 Inferred (8.85gpt) Gold Ounces

VANCOUVER, BC / ACCESSWIRE / June 12, 2024 / Grande Portage Resources Ltd. (TSXV:GPG)(OTCQB:GPTRF)(FSE:GPB) ("Grande Portage" or the "Company") is pleased to report an updated NI 43-101 Independent Mineral Resource Estimate for its 100% controlled Herbert Gold Deposit located in S.E. Alaska.

The Mineral Resource Estimate has a base case mineral resource cut to 181 grams per tonne gold (gpt Au). The Mineral Resource is reported at a 2.5 gpt cutoff grade and consists of:

• An Indicated Resource of 1,438,500 ounces of gold at an average grade of 9.47 gpt Au in 4,726,000 tonnes.
• An Inferred Resource of 515,700 ounces of gold at an average grade of 8.85 gpt Au in 1,813,000 tonnes.
• An Indicated Resource of 891,600 ounces of silver at an average grade of 5.86 gpt Ag in 4,726,000 tonnes.
• An Inferred Resource of 390,600 ounces of silver at an average grade of 7.33 gpt Ag in 1,813,000 tonnes.

Highlights:

• 34 diamond drill holes from 8 separate pads totalling 15,611 m (~51,000 ft) are added to the database which now total 240 holes.
• The Z and M pad drilling tested the western portion of the deposit and tightened the spacing on high-grade mineralization in the Goat Hanging Wall, Goat and Sleeping Giant veins, increasing the confidence level.
• The AB, P, Q, and BB pad drilling tested the eastern and deeper portions of the deposit and identifying new high-grade mineralization in the Sleeping Giant (15.42 gpt gold/2.1 m) and extending the Goat Hanging Wall, Goat, Sleeping Giant, Ridge, Main Hanging Wall and Main veins to the east and to depth.
• Deepest mineralization intersected to date on the property at -400m AMSL in 21Q-4 (20.9 gpt gold/0.9m) in the Main Vein (outcrops at 185m AMSL).
• Mineralization is open on all veins and uncorrelated intercepts located in sparsely drilled areas north and south of the Deep Trench Vein, and north of the Goat Hanging Wall Vein.

Commenting on these results, Ian Klassen, President and CEO of Grande Portage stated: "We are very pleased to present an updated independent Mineral Resource Estimate for the Herbert Gold deposit, the result of continued dedication and hard work from the entire team. The overall number of ounces and grade has increased since we announced our previous resource estimate in 2021. This estimate includes drilling from the past 3 drill seasons (2021-2023) and was designed to both maximize expansion while also adding greater model definition through in-fill drilling in the Goat Hanging Wall, Goat Main Vein, Ridge Vein Hanging Wall, Main Vein North Strand and Deep Trench Vein".

Mr. Klassen continued: "This resource estimate will provide the basis for a Conceptual Plan which is well underway and will be completed later this summer. Essentially, this document is intended to deliver a detailed outline of how the Herbert Gold deposit can be developed using a Direct Shipping Ore approach thereby greatly limiting any footprint on site. This objective offers low environmental impact with no mill, no chemicals, no on-site tailings, making the project notably simpler to permit, build and operate. Among other details it will address; initial mine access design plans, complete resource modeling, refinement of proposed stope shapes, assess possible mine production schedules with completed surface infrastructure & economic modeling.

Silver occurrences are associated with the gold values in the Herbert Deposit especially in areas with strong galena mineralization, with specific concentrations noted in the Main Vein where it enters the metasediments to the west.

The updated NI 43-101 mineral resource estimate, prepared by DRW Geological Consultants Ltd., uses a total of 240 drill holes and 7 channel cuts to calculate the Mineral Resource. At total of 5,810 samples were assayed for gold and 3,755 samples were analyzed for additional pathfinder elements. All unassayed sections of core are assumed to be 0 gpt gold. All 1.5 m x 8 m x 8m blocks require a minimum of 2 and a maximum of 8 composites within 100 m to be estimated. All blocks must be at least 50% within the solid model that describes the vein to be considered. Blocks that are within 60 m of a drill hole are considered Indicated and all other blocks are categorized as Inferred.

Sensitivity tables are shown below at various cutoff grades.

Indicated Resource cut to 181 gpt.

Inferred Resource cut to 181 gpt.

Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resources will be converted into Mineral Reserves. The estimate of Mineral Resources requires assumptions that are believed to be reasonable and may be materially affected by environmental permitting, legal, title, taxation, sociopolitical, marketing, or other relevant issues.

All quantities are rounded to an appropriate significant figure and sums may not add up due to rounding.

Indicated Mineral Resource by Vein, Cut to 181 gpt.

Inferred Mineral Resource by Vein, Cut to 181 gpt.

QA/QC Statement

Drill core was boxed on site by the drill contractor and was slung by helicopter in supersacks to a nearby pickup area where it was received by Company crew. The core was laid out on logging tables in the Company's warehouse by crew or when the tables were full, stored on pallets in the front open area inside. The geotech crew converted all marker blocks in boxes into metric numbers, straightened and arranged the core to approximate original bedrock and cleaned the core in preparation for photographing. Geotechnical information was gathered at this point. Core recovery, RQD measurements and rock competency determinations were noted. Geologists then marked the core and boxes for intervals that were sampled and placed the numbered sample tag at the start of the interval. Tags were stapled at the start of the interval to be sampled so the number is clearly visible in the photographs. Tags were reserved and removed from the sequence in the boxes at this point and blanks and standards were inserted. Sample tickets have two tear-off tags; one was placed in the core box, and one was placed inside the sample bag.

Certified standards were inserted at the rate of 5%, or one for every 20 samples and blanks were used at the same rate in general except that they were inserted after high grade intercepts were expected or noted. Photos of each box were taken by the geotechnician with the label board clearly and accurately marked for hole number, box number, and footage. Photos were given to the project geologist on SD card for renaming files and storing in master computer. The core was logged by a Company geologist after photographing. The geologist would confirm that the hole or part of the hole was through being logged, the geotech crew saws/splits the sample intervals. The splitter determines how best to cut the core so both halves are equally mineralized and also maintain the structural integrity of the remaining half so future inspection is most meaningful. Sample intervals were sawn and bagged with plastic bags used inside of cloth bags for highly broken, powdered, gougey, crumbly, or clay-rich samples or just canvas bags for competent intervals. Sample tags for that interval were placed inside the bag with the sample and the sample number written on the outside of the bag in permanent marker.

The sample saw was kept clean with care taken after cutting samples from a known high grade mineralized zone. Samples were then placed inside the secure warehouse in the area reserved for shipment preparation. Blanks and standards were added to the samples for shipment using the tags which were reserved out of the sequence while first marking the intervals to be sampled earlier.

Samples were aggregated in larger rice bags, labeled for shipment and in 2021 hauled to the local Bureau Veritas prep lab in Juneau where they processed the samples according to the sample transmittal form submitted with the samples. The pulps were then shipped to Bureau Veritas assay lab in Richmond, B.C. for the following techniques: PRP70-250, FA430 with FA550 on over limits, as well as MA300 with over limits for W using LF100 and over limits for As by AQ370. Selected samples were run using metallic procedure FS63201kg or FS632-500g. BVI is independent of the Company and is ISO 9001:2015 certified. In 2022 and 2023 the samples were prepared similarly by sent to ALS Canada Ltd. in North Vancouver facilities using conventional preparation techniques and analyzed using Au-ICP21 for gold with screened metallic analyses for samples where visible gold was noted. ME-MS41 techniques were used to determine additional element concentrations. Blanks and standards were inserted in the field as well as in the laboratory with all checks reporting acceptable results. ALS in independent of the Company and certified ISO-17025.

The Qualified Person's opinion is that the Company's sample preparation, security and analytical procedures were and are appropriate for this project.

Nine wire-frame models were created based on geology and the assay distribution observed in individual drill logs as viewed in 3D. Composites (1.5m) were capped at 181 gpt gold and clipped to the wire-frames which were populated with 1.5m x 8m x 8m blocks rotated into the plane of the veins which had grades estimated using inverse distance squared techniques using 100 m search radius for a minimum of 2 and maximum of 8 composites. Blocks within 60 m of composites are considered Indicated Mineral Resources and blocks between 60 and 100 m are considered Inferred Mineral Resource. The resource assumes underground minin