Mr. Ian Klassen reports

GRANDE PORTAGE ANNOUNCES OUTSTANDING RESULTS FROM SENSOR-BASED ORE SORTING TESTWORK, WITH GOLD GRADE OF SAMPLE INCREASED BY 120%

Grande Portage Resources Ltd. has released results from testwork of a sensor-based ore-sorting system, utilizing a composite core sample from the New Amalga mine project located approximately 16 miles (25 kilometres) northwest of the city of Juneau.

Ian Klassen, president and chief executive officer, commented, "We are extremely pleased with the results of the testwork with the Steinert ore-sorting equipment, which demonstrated excellent ability to identify and reject the unmineralized particles within the sample of New Amalga material, resulting in a 120-per-cent increase in gold grade and a 57-per-cent reduction in mass with very minimal gold loss."

Mr. Klassen continued: "These results are game changing for a host of reasons. Integrating ore sorting into the conceptual mine production plan significantly reduces the amount of mined rock requiring transportation and processing at a third party facility, lowering per-ounce costs and also providing useful sorter-reject material for underground backfill, all without the use of chemical processing reagents. This further enhances the existing advantages of our proposed direct-ship mine configuration, which utilizes off-site processing. As demonstrated by the test results, it may also create opportunities for inclusion of thinner veins into the mine plan -- areas of the deposit which otherwise may not have been considered viable."

Background

As previously announced, the company's conceptual mining plan envisions the future development of the New Amalga gold mine as a selective underground mining operation, which would send ore off-site to be processed at a third party facility, enabled by the project's location near tidewater and fewer than four miles (6.5 km) from existing paved highway. This results in a dramatically reduced mine site footprint due to the avoidance of chemical processing and tailings storage facilities.

The purpose of ore sorting is to quickly separate particles of waste dilution rock from the mined material, without the use of chemical reagents. The goal is to significantly reduce the volume of material that would be transported off-site to a third party processing facility.

Grande Portage assembled a drill core composite, which included both ore and waste material, to reflect the dilution from wall rock (waste), which is inherent with underground blasting of narrow ore veins. The core composite was subjected to a sensor-based ore-sorting test process at the facilities of Steinert U.S. Inc., a leading global manufacturer of ore-sorting equipment.

Technical description of ore-sorting test process

Sensor-based ore sorting can utilize a variety of measurements to determine whether a particle is ore or waste, including colour, electromagnetic induction, laser and X-ray analysis to assess elemental composition. The crushed rock is placed on a conveyor belt and then passed in front of the sensor, which rapidly analyzes the individual pieces of rock. When a piece of rock is identified as waste, a puff of compressed air redirects it to a reject bin. The remining pieces of rock are sent to the accepted product stockpile.

Fine particles too small to effectively sort are typically combined with the product stockpile since higher-grade material tends to produce more fines during blasting and crushing due to the higher sulphide content and brittle nature of the quartz vein rock.

For the testwork, a series of reference samples was analyzed by the sorter machine, reflecting core material of various categories, including high-grade ore, mid-grade ore, low-grade ore and waste. This allowed the sorter to learn the characteristics of each type of material to generate a sorting algorithm. Each of these reference samples was sourced from multiple drill holes at various locations within the deposit to capture any spatial variability in the rock characteristics.

After the sorting algorithm was developed, the composite sample was fed into the sorter machine. This composite was sourced from multiple drill holes in various areas of the deposit distinct from the reference samples. It included approximately 55 per cent wall rock and 45 per cent vein rock, reflecting potential waste dilution within run-of-mine material to simulate mining an area of vein narrower than the minimum mechanized mining width.

In addition to the product material, three splits of reject material were generated from sorting the sample at progressively increasing level of selectivity, reflecting operation of the machine at various degrees of sorting criteria. All material was then assayed at SGS-Lakefield.

All three reject splits returned assays below the level which would be considered viable to transport and process at a third party facility, and were therefore classified as waste, indicating that the highest level of sorter selectivity is appropriate. In total, the sorter rejected 57 per cent of the feed material, indicating excellent alignment with the approximately 55-per-cent-wall-rock content of the composite sample.

Additionally, all material was screened before assay to collect unsortable fines, which were assayed separately. This confirmed that the fines contained a high degree of gold mineralization and are appropriate to combine with the product sample. A full table of results is shown below.

A short video of the testwork process is available on YouTube.

Kyle Mehalek, PE, is the qualified person within the meaning of National Instrument 43-101, and has reviewed and approved the technical disclosure in this release. Mr. Mehalek is independent of Grande Portage within the meaning of NI 43-101.

About Grande Portage Resources Ltd.

Grande Portage is a publicly traded mineral exploration company focused on advancing the New Amalga mine project and the outgrowth of the Herbert gold discovery situated approximately 25 kilometres north of Juneau, Alaska. The company holds a 100-per-cent interest in the New Amalga property. The New Amalga gold system is open to length and depth, and is host to at least six main composite vein-fault structures that contain ribbon structure quartz-sulphide veins. The project lies prominently within the 160-kilometre-long Juneau gold belt, which has produced over eight million ounces of gold.

The company's updated NI 43-101 mineral resource estimate reported at a base-case mineral resources cut-off grade of 2.5 grams per tonne gold and consists of: an indicated resource of 1,438,500 ounces of gold at an average grade of 9.47 grams per tonne Au (4,726,000 tonnes); and an inferred resource of 515,700 ounces of gold at an average grade of 8.85 g/t Au (1,813,000 tonnes), as well as an indicated resource of 891,600 ounces of silver at an average grade of 5.86 g/t Ag (4,726,000 tonnes); and an inferred resource of 390,600 ounces of silver at an average grade of 7.33 g/t silver (1,813,000 tonnes). The MRE was prepared by Dr. David R. Webb, PhD, PGeol, PEng (DRW Geological Consultants Ltd.) with an effective date of July 17, 2024.

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