Riverside Resources Intersects Near-Surface Gold And Base Metal Mineralization At Union Norte And Advances Multiple Targets For Phase 2B Drilling

Union Mine Target

UND26-013 was collared to test the southward extension of the Sproul manto; a previously mined orebody. The drill hole was successful in finding Pb and Zn mineralization and intercepted the replacement body south of the known artisanal workings. Anomalous Pb (>36 ppm) and Zn (0.1-0.7%) values confirm proximity to the CRD replacement body (Figure 3). Deeper drilling is warranted to intersect the interpreted main feeder structure beneath the Union Mine, where the highest-grade results on the project were obtained (20.2 g/t Au, 226 g/t Ag, 2.7% Zn over 30 m; (see news release, January 22, 2026 ). Further drilling at the Union target can drill the newly identified IP features including the geologic targets that were progressed during the 2026 exploration work.

Figure 3 : Drill Section (30 m thickness) through the Union Mine Target (looking north); section line B-B' Figure 1.

Additional Phase 2A Targets

Jabali and Luis Hill Targets

Drill hole UND26-017, drilled southward toward the Jabali target, improved the understanding of the structural controls in this area. Elevated As values (10 – 80 ppm, Figure 4) indicate proximity to a feeder zone similar to those observed at Union Norte and the Union Mine and identified in the drill hole.

An IP survey at the project included lines at Jabali and Luis Hill with targets delineated as chargeability highs for both areas, particularly at Luis Hill, with the anomaly extending over 1 km along strike and 300 m at depth. This IP feature at Luis Hill coincides with the sediment-hosted gold mineralization identified in Phase 1 drilling. The anomaly remains open along strike and at depth, significantly expanding the exploration footprint for this target Hole UND26-18 was drilled above the anomaly and terminated prior to reaching the 150 m planned target depth due to complications. Follow up drilling for Jabali and Luis Hill are warranted.

Figure 4 : Drill Section (30 m thickness) through the Jabali Mine (looking northwest); section line C-C' Figure 1.

Seven holes totaling 530.1 metres were completed during Phase 2A. Significant faulting within the targeted formations slowed core drilling and limited progress and recovery in several holes. To improve drilling efficiency in these ground conditions, the Company is actively evaluating a reverse-circulation contractor for Phase 2B. The change in drilling method is intended to increase penetration rates and improve access to priority targets while preserving the option to use diamond core where detailed geological information is required.

Table 2: Drill Collar Information for Drill Holes

Next Steps – Phase 2B

Drilling has been successful, with the first portion of the Phase 2 program meeting its objectives and delivering positive exploration results at both the Union mine and Union Norte targets. Restarting and continuing drilling at Union is warranted, with multiple targets identified, particularly those building on the recent drilling and geophysics completed at the property.

General Overview of La Union Project and Drill Coordinates

The Project is summarized in the published NI 43-101 Technical Report and, more briefly, on the Riverside website. Riverside initially acquired the Project and subsequently consolidated additional inlier mineral claims to build a strong land position. The company then advanced the Project through surface access agreements and drill permitting, making it a turnkey exploration opportunity for the Optionee.

At the Project, historical mining by Peñoles Mining Company targeted chimney and manto-style replacement bodies within the upper oxide zones. As a result, the underlying sulfide zones represent immediate drill targets for further exploration.

The Project features favorable limestone host rocks, an extensive alteration footprint, and multiple small-scale historical workings, with mineralization styles similar to those at the Hermosa Project in southern Arizona. At Hermosa, South32 is advancing mine development after acquiring the project from Arizona Mining for over $400 million, and Hermosa is now considered one of Arizona's most promising upcoming mining operations.

At La Union, immediate drill targets offer the potential for significant-scale discoveries. The Project is well positioned for near-term exploration results, with targets that include both oxide and deeper sulfide mineralization.

Qualified Person & QA/QC

The scientific and technical data contained in this news release pertaining to the Project was reviewed and approved by Julian Manco, P.Geo, a non-independent qualified person to Riverside Resources Inc., who is responsible for ensuring that the information provided in this news release is accurate and who acts as a "qualified person" under National Instrument 43-101 Standards of Disclosure for Mineral Projects.

All drill core samples were sawn in half, labeled, and bagged on site. The remaining half-core was retained and securely stored. Numbered security tags were applied to all sample shipments to ensure chain of custody. Samples were submitted to SGS's analytical facility in Hermosillo, Sonora, Mexico, for sample preparation and analysis. SGS is independent of the Company.

Analytical methods include fire assay for gold, gravimetric finish for high-grade silver, multi-element ICP digestion, and high-range fusion-ICP for over-limit concentrations.

The Company's QAQC program includes certified reference materials (CRMs), field blanks, and field duplicates inserted at regular intervals throughout each sample batch. CRM performance has had no failures yet identified and is evaluated using a Z-score criterion, where Z = (observed − certified value) / standard deviation, with acceptance thresholds of PASS (|Z| ≤ 2), WARNING (2 < |Z| ≤ 3), and FAIL (|Z| > 3). Field duplicate precision is assessed using relative percent difference (RPD), with PASS ≤ 20%, WARNING > 20–30%, and FAIL > 30%. Blanks are evaluated against the gold detection limit, with any result above that threshold flagged for investigation. Results below detection limits are retained as reported and excluded from RPD calculations. No QAQC failures have been found in the batches associated with the results reported herein.

About Riverside Resources Inc.

Riverside is a well-funded exploration company driven by value generation and discovery. The Company has a solid balance sheet with no debt and fewer than 95M shares outstanding with a strong portfolio of gold-silver and copper assets and royalties in North America. Riverside has extensive experience and knowledge operating in Mexico and Canada and leverages its large database to generate a portfolio of prospective mineral properties. Riverside has properties available for option, with information available on the Company's website at .

ON BEHALF OF RIVERSIDE RESOURCES INC.

"John-Mark Staude"

Dr. John-Mark Staude, President & CEO

For additional information contact:

Certain statements in this press release may be considered forward-looking information. These statements can be identified by the use of forward-looking terminology (e.g., "expect”,” estimates", "intends", "anticipates", "believes", "plans"). Such information involves known and unknown risks -- including the risk that the Transaction will not be completed as contemplates, or at all, availability of funds, the results of financing and exploration activities, the interpretation of exploration results and other geological data, or unanticipated costs and expenses and other risks identified by Riverside in its public securities filings that may cause actual events to differ materially from current expectations. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release.

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