Metallis Prioritizes High Impact Drill Targets At Greyhound Property, Idaho

VANCOUVER, May 21, 2025 - Metallis Resources Inc. (TSX-V: MTS; OTCQB: MTLFF) (the "Company" or "Metallis") is pleased to provide an update on the progress at the Greyhound Property (the "Property"), including prioritization of drill targets for the 2025 season. The Property contains a high-grade silver/gold/antimony prospect within the historic Stibnite (antimony mineral) Mining Camp, located in central Idaho, USA. Mineralization at the Property is hosted within a 3.5 km long shear zone with multiple historic mining adits, yet it has never been drill-tested. Extensive data compilation and geological work has identified multiple prospective showings including 3 high-priority drill ready targets scheduled for drilling this summer.

Dave Dupre, Metallis' VP of Exploration commented, "The 3.5 km shear zone at Greyhound compares favorably with many other silver mines within Idaho's world-renowned Silver Valley. Historic underground channel sampling at the 1350' target revealed exceptionally high-grade mineralization, confirming the shear is extremely well endowed. Grab sample assays of 121.4 g/t AuEq* in the Rufus Adit, 55.2 g/t AuEq* at the Bulldog and 66.3 g/t AuEq* at the Birdie highlight the incredible potential of the Greyhound Property. It's rare to find such a rich historical project that has never been drilled, and we're excited and fortunate to be the group taking this next step to unlock its full potential. "He went on to add, "Greyhound's strategic value is enhanced by its multi-metal profile, with antimony contributing 15% of the in-situ value alongside silver and gold. This has gained increased significance following China's export restrictions on antimony, a critical metal for defense, energy and semiconductor applications. Importantly, Greyhound can be developed primarily based on silver/gold economics, which reduces antimony-related risks while maintaining a strategic supply potential."

Next Steps

• Drone Magnetic Survey: This survey will be initiated to pinpoint the location of the shear in areas of overburden and help identify important mineralizing cross structures.
• Induced Polarization Survey: The chargeability data will be used to highlight the thickest zones of high-grade mineralization and aid in refining drill targets.
• Drill Targets: Metallis has focused on three high-priority targets for 2025 drilling: 1350', Bulldog, and Birdie.
• Permits: As the proposed work is on patented claims, only one minor permit is required for the proposed work.
• Service Providers: The team is in the process of qualifying bids from multiple service providers.

Proposed 2025 Drill Targets

The three highest-priority drill targets were identified by interpretation of historic results and extensive work by the Metallis team over the last year. These targets will be tested with multiple drillholes in a program planned to total 2,000 m. No drilling has ever been conducted on the property so all targets will see their first ever drill testing during the inaugural program planned for the upcoming field season. The three highest priority drill targets are described below.

1350' Target

Drilling at the 1350' will be used to expand a high-grade silver/gold/antimony zone mined historically in the 1980's with multiple drill holes focused above and below the Lower Rufus adit. Historical channel sampling^† along a 36.9 m length of this adit returned 1.85 g/t Au and 785 g/t Ag (10.6 g/t AuEq*), confirming a high-grade mineralized shoot exists at this location. Three grab samples taken historically from this same zone also provided high-grade results up to: 3.27% Sb, 8,770 g/t Ag, 1.87 g/t Au, 18.7% Pb, and 20.8% Zn.

Prospective areas above and below the 1350' mineralized zone will be targeted for drilling during the 2025 season as historic mining has only tested one of this extensive shear system. Vertical extensions of the mineralized zones have been validated through multiple mining raises and historic descriptions. Vertical continuity can be traced to a surface trench located 200 m above the adit that returned 2.0 g/t AuEq* over 4 m with 3 nearby float samples returning grades > 10 g/t AuEq*. Given the long strike length of the Greyhound shear system, it is probable that there is significant depth potential on the property, including at the 1350' zone. This can be exemplified by Idaho's currently operating Lucky Friday mine operated by Hecla Mining, that reaches a total depth of 2,922 m below surface making it the deepest mine in the USA.

Bulldog Target

The Bulldog target has demonstrated rich antimony mineralization as well as very strong gold and silver results from sampling completed by Metallis in 2024. Highlights include chip sampling that returned 353 g/t Ag and 0.61% Sb over 3 m, including a 15 cm high-grade quartz sulfide vein, outcropping over 13 m in length, that produced an average of 2.68% Sb, 1,624 g/t Ag and 0.60 g/t Au from 4 samples (27.9 g/t AuEq*). This vein was missed by the former operator when excavating a surface cut and speaks to the well-endowed system as they prioritized mineralization adjacent to this vein. A very high-grade antimony sample has also been returned from a nearby stockpile that contained 4.54 % Sb.

A functioning access road was built to this target to accommodate a historic surface cut from the 1980's and a historic adit from the early 1900's. This road will be utilized for efficient drill testing and will improve economics for the upcoming drill program. The Bulldog represents one of the largest areas of exposed mineralization at surface and the shear zone is up to 15 m across with multiple anastomosing quartz sulfide veins that total 3 m. This target has also never been drilled, and the geological team intends to test this high-grade mineralization with multiple planned drillholes.

Birdie Target

Significant gold and silver were found at the Birdie target, where two trench cuts located 70 m apart as well as historic adits both revealed a sizeable shear zone with quartz sulfide veins of 1-3 m width. An 80 cm block from Upper Birdie cut yielded 4,900 g/t Ag with other grab samples nearby returning up to 67.0 g/t AuEq*. A 50 cm quartz sulphide vein sampled from Lower Birdie cut returned 18.15 g/t Au, and six out of seven samples from the phase-two program at the Lower Birdie returned >1.8 g/t Au. These findings emphasize the Birdie as a gold rich zone and highlight the exceptional gold values that were overlooked historically. This target is located on a parallel trend to the main Greyhound shear and suggests additional potential lies in adjacent shear zones that have not been well explored. Access is along a previously constructed road allowing for convenient adjustments and expansion drilling.

About the Greyhound Property

In February 2024, the Company optioned the Greyhound Property which is located in Custer County, Idaho, approximately 42 km northwest of the town of Stanley and 35 km south of Perpetua Resources' Stibnite gold mine. This property was the center of an active silver mining camp in the early 1900's and at one point contained a smelter and two active mines situated along a 3.5 km shear.

The Greyhound targets are hosted by prominent shear zones with polymetallic quartz - sulphide veins containing elevated concentrations of Au, Ag, Sb, Pb and Zn. They are comparable to numerous mines in North Idaho's Silver Valley along Interstate 90. This famous district is one of the most prolific silver districts in the world. The total quantities produced are impressive: over a billion ounces of silver, 3 million tons of zinc, and 8 million tons of lead totaling over $6 billion in value, ranking the Silver Valley among the top ten mining districts in world history.

QAQC

All the rock samples were kept under the control of Metallis staff until they were delivered directly to the ALS laboratories Ltd. sample preparation facility in Twin Falls, Idaho (an independent certified laboratory facility). Analyses were then completed by ALS in Vancouver. Blanks and standards have been added to the samples stream by ALS along with internal QAQC protocol. All the samples were initially analyzed by the Ultra Trace technique. Results that returned values greater than a pre-determined threshold were then analyzed by element - specific methods as noted below:

• ME-MS 41: Ultra Trace Aqua Regia ICP-MS.
• ME-GRA21: Au, Ag 30g Fire Assay - Gravity Finish
• Pb-OC46: Ore Grade Pb - Aqua Regia
• Zn-OC46: Ore Grade Zn - Aqua Regia
• Sb-ICP08: Sb - KCl/HCl digestion ICP-MS
• As-OC46: Ore Grade As - Aqua Regia

A grab sample is taken from a rock outcrop that is being assessed for the presence of valuable elements and are therefore selective. They are solely designed to show the presence or absence of mineralization and are not intended to provide nor should be construed as a representative indication of grade or mineralization at the Property.

Chip-channel sampling involves taking contiguous rock chip samples along a line to define the width and grade of a zone. Commonly, these are taken perpendicular to the strike of the mineralized zones

^†The grades of the Greyhound 1350' zone are historical and cannot be verified by Metallis although there is no reason to believe they are inaccurate.

*Gold and Silver equivalent values are derived from the following prices in USD; Au $2,500 per ounce, Ag $28 per once, Pb $0.90 per pound, Zn $1.20 per pound, Sb $12.00 per pound

Qualified Person

David Dupre, P.Geo, Vice President - Exploration and the Qualified Person, as defined by National Instrument 43-101, has reviewed, and approved the technical information contained in this release.

About Metallis

Metallis Resources Inc. is a Vancouver-based company focused on the exploration for gold, copper and silver on its flagship 100%-owned Kirkham Property in Canada, situated in northwest British Columbia's Golden Triangle, and on the Greyhound Property, a gold/silver/antimony target in Idaho, USA.

Metallis trades under the symbols MTS on the TSX Venture Exchange, MTLFF on the OTCQB Exchange, and 0CVM on the Frankfurt Stock Exchange, and has 75,305,003 common shares outstanding.

On behalf of the Board of Directors:

/s/ "Fiore Aliperti"
Chief Executive Officer, President, and Director

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SOURCE Metallis Resources Inc.