STLLR Gold Delivers Remaining Assay Results With Encouraging Gold Mineralization from its Hollinger Tailings Project

Press Release

TORONTO, Ontario, August 7, 2025 – STLLR Gold Inc. (TSX: STLR) (OTCQX: STLRF) (FSE: O9D) (“STLLR” or the “Company”) is pleased to report the remaining results from its 2025 characterization program at the Hollinger Tailings Project (“Hollinger” or the “Project”) located in the Timmins Mining Camp, Ontario, Canada.

Key takeaways from the Hollinger characterization program:

• Consistent grade profile: Results from the program demonstrate uniform grade distribution across drilled intervals. Most holes returned mineralized values throughout their full length.

• Grade Trends Within Hollinger: The Company observed higher gold grades in Phase 1 (the northern portion of Hollinger; see Figure 1), particularly near the southern end where the historical tailings dam wall is located. Overall results support the economic potential of Hollinger and its further advancement towards a mineral resource estimate and metallurgical testing.

• Metallurgical Testing and Mineral Resource Modelling Underway: STLLR has initiated metallurgical testing of the Hollinger material, with a mineral resource estimate to follow. Results from both programs are expected in the second half of 2025.

• Further Characterization Opportunities: While the 2025 program successfully covered the majority of the Hollinger deposit, certain areas—such as the ponds and the eastern extent of Phase 1—remain to be characterized in future phases to further enhance the dataset.

Table 1: Hollinger Characterization Program Assay Highlights (For more information see Tables 2 & 3 and Figures 1 to 5):

Keyvan Salehi, P.Eng., MBA, President, CEO, and Director of STLLR, commented: “We’ve concluded the assaying of the successful 2025 Hollinger characterization program. We are pleased with the consistent gold mineralization across the facility and are encouraged by the gold grades we have observed. We remain encouraged by Hollinger’s economic potential at current gold prices. The results of the metallurgical testing program and the mineral resource estimate are key data points that can allow us to assess Hollinger’s near-term cash flow potential.”

Hollinger Characterization Program

Located in southeast Timmins, Ontario, the Hollinger Tailings Project holds tailings from the historic Hollinger Mine, once the world’s largest gold mine. Operating from 1910 to 1968, it produced 19 million ounces of gold at an average grade of 9.9 grams per tonne.[1]  The site contains an estimated 50–60 million tonnes of tailings. Recent amendments to Ontario’s Mining Act[2] have streamlined the permitting process for reprocessing historical tailings, aligning economic opportunity with environmental remediation. Given current gold prices and the potential for low capital intensity, STLLR believes Hollinger presents significant opportunity for value creation.

STLLR’s comprehensive characterization program is designed to assess the Project’s potential and information gathering for a recovery permit and remediation plan. The Company has completed 11,223 metres of sonic drilling across 423 holes, spaced on a 50 m grid pattern. Assay results demonstrate consistent gold mineralization across the facility. The Company is currently advancing a metallurgical testing program to evaluate recovery potential, with results and a mineral resource estimate targeted for release in the second half of 2025. Please review Figures 1 to 5 and Tables 1 to 3 for further context.

[1] Hollinger Historical Production Statistics, Geology Ontario database: https://www.geologyontario.mines.gov.on.ca/persistent-linking?mineral-inventory=MDI42A06NW00007

[2] Ontario’s new “Mining Act for Recovery of Minerals” regulation to be in effect July 1, 2025. For more details:  https://news.ontario.ca/en/release/1005407/ontario-supporting-recovery-of-residual-metals-and-minerals

Figure 1: Hollinger Characterization Program – Drill Location Map

Figure 2: Hollinger Characterization Program – Zoomed In Drill Location Map #1

Figure 3: Hollinger Characterization Program – Zoomed In Drill Location Map #2

Figure 4: Hollinger Characterization Program – Section “A-B” Looking North

Figure 5: Hollinger Characterization Program – Section “C-D” Looking North

Table 2: Hollinger Characterization Intercepts*

*Note: Included intercepts are calculated using a 0.5 g/t Au cut-off and a maximum of 2 m internal dilutions

Table 3: Hollinger Characterization Hole Details

Quality Control Procedures

Tailings core is collected by four-inch diameter continuous sonic coring. Tailings samples are cut, with half sent to ALS Laboratories Inc. (ALS) for drying to a maximum temperature of 60-degree Celsius. The samples are then sieved through a -180 µm screen (Tyler 80 mesh) to a 1.00 kg split of homogenize minus fraction material. A 50 g charge is Fire Assayed and analyzed using an AAS finish for Gold. Samples above 10.00 g/t Au are analyzed by Fire Assay with a gravimetric finish. ALS is an ISO 17025 accredited laboratory.  STLLR inserts independent certified reference material and blanks with the samples and assays routine pulp repeats, as well as completing routine third-party check assays at Bureau Veritas Commodities Canada Ltd.

Qualified Person

John McBride, MSc., P.Geo., Vice President of Exploration for STLLR, who is the “Qualified Person” as defined by NI 43-101 for this project, has reviewed and approved of the technical disclosure contained in this news release.

About STLLR Gold

STLLR Gold Inc. (TSX: STLR; OTCQX: STLRF; FSE: O9D) is a Canadian gold development company actively advancing high-potential gold projects in Canada: The Tower Gold Project and the Hollinger Tailings Project in the Timmins Mining Camp in Ontario and the Colomac Gold Project located north of Yellowknife, Northwest Territories. Tower and Colomac have the potential to become large-scale, long-life operations and are surrounded by exploration land with favourable upside potential. Hollinger has the potential for near-term value creation. STLLR’s experienced management team, with a track record of successfully advancing projects and operating mines, is working towards rapidly advancing these projects.

Contact Us

STLLR Gold Investor Relations

+1 (416) 863-2105 | investors@stllrgold.com | www.STLLRgold.com

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