Martello Update

Richmond Hill Resources PLC
(“Richmond Hill” or the “Company”)

Martello Update

Richmond Hill Resources plc (AIM: RHR) is pleased to provide an exploration update from its wholly owned Martello Gold Project in Ontario, Canada, including results from the recent Tabor drill programme, completion of a district-wide historical data compilation and interpretation of a property-wide drone magnetic survey and 3D magnetic inversion model.

HIGHLIGHTS

• Independent target ranking identified seven priority exploration targets across the Martello Project, with Sakoose emerging as the highest-ranked exploration area.
• The interpretation suggests that the Sakoose area may contain multiple subparallel structures rather than a single mineralised vein and was further resolved into five subordinate prospecting targets surrounding the historic mine workings.
• Exploration permit application covering Sakoose and other priority targets submitted to Ontario Ministry of Energy and Mines.
• Five of seven drill holes completed at Tabor were designed as step-out holes testing extensions to the historically defined high-grade shoot.   Only TB-26-001 and TB-26-002 directly targeted the previously recognised high-grade core of the Tabor system.
• Both core-zone holes intersected the target area and returned multiple gold-bearing intervals associated with stacked quartz vein systems.
• Visible gold was observed in drill core from TB-26-002.
• Property-wide drone magnetic survey and 3D magnetic inversion modelling completed across the Martello Project.
• Integration of drilling, historical exploration data and district-scale geophysics has resulted in an improved understanding of the geological relationships between the principal gold occurrences across the Martello Project.
• Sakoose historically produced gold at grades of approximately 15 g/t Au from a limited portion of a structure interpreted to extend for more than 1.4 kilometres. Multiple gold-bearing veins and structures have been documented across the Sakoose area and the system remains open along strike and down plunge.

TABOR DRILL PROGRAMME

The Company's maiden drill programme at Tabor was designed to validate historical exploration results, test extensions to known mineralisation and provide geological information for integration into the Company's district-wide geological model.

Five of the seven drill holes completed during the programme were designed as step-out holes testing potential strike extensions to the historically defined high-grade shoot. Only two holes (TB-26-001 and TB-26-002) directly targeted the previously recognised high-grade core of the system. TB-26-003 to TB-26-007 were step-out holes or geological tests designed to evaluate extensions to, and the broader geological setting around, the established mineralised zone.

Both core-zone holes intersected the target area and returned multiple gold-bearing intervals associated with stacked quartz vein systems. Visible gold was observed in TB-26-002. The visible-gold interval returned a metallic screen fire assay of 3.15 g/t Au over the same interval.

Several of the step-out holes tested areas beyond the limits of previous drilling. The programme has therefore provided geological information on the extent, geometry and controls of the Tabor system, rather than representing infill drilling within the known high-grade zone.

Tabor Assay Results - Intervals Greater Than 0.5 g/t Au

Hole	From (m)	To (m)	Width (m)	Au g/t
TB-26-001	103.15	103.90	0.75	2.15
TB-26-001	141.40	142.50	1.10	0.56*
TB-26-001	150.6	151.4	0.8	0.63
TB-26-001	156.16	157.20	1.04	0.86
TB-26-002	69.60	70.30	0.70	1.20
TB-26-002	74.80	75.35	0.55	0.63
TB-26-002	75.35	76.00	0.65	1.02
TB-26-002	84.50	85.80	1.30	1.71
TB-26-002	100.25	101.65	1.40	1.42
TB-26-002	103.57	104.45	0.88	0.53
TB-26-002	161.50	162.20	0.70	3.15†

* Composite interval calculated from two consecutive samples: 141.40-142.00 m at 0.518 g/t Au and 142.00-142.50 m at 0.601 g/t Au.

† Value shown is the metallic screen fire assay; the initial fire assay over the same 0.70 m interval returned 2.80 g/t Au.   All widths are downhole widths; true widths have not been calculated.

The Company notes that Tabor exhibits characteristics typical of a coarse-gold system, including visible gold and highly localised mineralisation. In such environments, gold distribution can be inherently irregular and individual assay intervals may not fully reflect the grade distribution within the broader mineralised structure.

HISTORICAL DATA COMPILATION

Over the past six months the Company has undertaken a comprehensive review and integration of historical exploration data across the Martello Project. The review incorporated historical mine records, assessment reports, geological mapping, drilling records, geophysical surveys and academic studies spanning more than a century of exploration activity.

DISTRICT-WIDE MAGNETICS AND 3D INVERSION MODELLING

The Company recently completed a drone magnetic survey across the Martello Project and commissioned a 3D magnetic inversion model covering the entire property package.

Historical mining, drilling and geological studies identified multiple gold occurrences across the Martello Project. The 3D interpretation provides a district-scale framework capable of explaining their distribution and has generated ranked exploration targets to test that model.

The integration of historical exploration records, district-scale geophysics and recent drilling has resulted in an improved understanding of the geological relationships between the principal gold occurrences across the Martello Project.

The interpretation indicates that the known gold occurrences are spatially associated with a common structural framework. Regionally, exploration is expected to focus on E-W to ENE-WSW structural corridors, which host known mineralisation at Tabor and Sakoose, with NW-SE structures also considered important as potential cross-cutting controls requiring further evaluation.

PRIORITY AREA - SAKOOSE

Independent target ranking identified seven priority exploration targets across the Martello Project, with Sakoose emerging as the highest-ranked exploration area.

Sakoose historically produced approximately 3,900 ounces of gold at grades of approximately 15 g/t Au. Subsequent drilling, including 26 holes completed by Venturex/Nexus confirmed high-grade mineralisation beyond the historic workings, including intercepts of up to 10.0 g/t Au over 6.86 metres. Later geological work suggested the broader Sakoose system may extend for more than 1.4 kilometres, and the system remains open to further exploration along strike and down plunge. The interpretation indicates that Sakoose lies within one of the most structurally complex areas identified across the property. The Sakoose area is interpreted to lie near the intersection of several geophysical and topographic lineaments that may represent faults or other structural controls. These interpretations require field verification.

The interpretation suggests that the Sakoose area may contain multiple subparallel structures rather than a single historical vein. At least four E–W-trending lineaments have been identified within the broader Sakoose corridor, locally intersected by NW–SE-trending structures, and several of these features coincide with gold-in-soil anomalies.

The Sakoose area was further resolved into five subordinate prospecting targets associated with interpreted structural intersections, magnetic flank positions and magnetic-low features surrounding the historic mine workings. These targets provide a framework for evaluating the potential for additional mineralised structures beyond those historically mined and drilled and support a broader multi-vein exploration model for the Sakoose area.

A deep-rooted magnetic source has been identified beneath the Sakoose area. The relationship between this magnetic feature and gold mineralisation remains untested by drilling and the Company does not currently interpret the magnetic response alone as evidence for continuity of gold mineralisation at depth.

ADDITIONAL TARGETS

The study also identified additional ranked targets across the Martello Project, including Tabor, Brockman & Highway 479, Martson, Long Lake McCracken, GPH-T7, New Church Lake / Bronger and other conceptual targets requiring follow-up exploration.

The interpretation has advanced the Company's understanding of Martello from a collection of historical occurrences into a ranked set of exploration targets.   The study provides a framework for prioritising exploration expenditure and drill testing across both established targets and previously unrecognised opportunities.

PERMITTING AND NEXT STEPS

The Company has submitted an exploration permit application covering Sakoose and other priority targets within the Martello Project. The application was formally circulated by the Ontario Ministry of Energy and Mines on 11 June 2026 and is currently progressing through the statutory consultation process.

The Company is integrating the target ranking generated by the interpretation with ongoing permitting activities and drill planning. Sakoose is expected to form the focus of the next phase of drilling, while surface validation and target refinement work will continue across Martello.

The Company believes the interpretation reduces geological uncertainty across the Martello Project and provides a framework for prioritising future exploration expenditure.

Hamish Harris, Executive Director, commented:

"This is an important step forward for Richmond Hill at Martello. In a single phase of work, we have completed our maiden drilling and, together with the recent 3D magnetic interpretation, brought together more than a century of exploration into a coherent geological framework. Much of the historical exploration across Martello was undertaken by different operators on fragmented land positions and focused on individual occurrences rather than the broader geological system. The rocks have not changed. The gold occurrences have not changed. What has changed is our ability to evaluate them as structurally related, rather than isolated, occurrences.

The Tabor drilling programme confirmed mineralisation within the previously recognised core of the system and provided important geological information from a series of step-out holes. However, in our view, the most significant outcome of this phase of work is the enhanced understanding of Martello and, in particular, the identification of Sakoose as the Company's highest-priority target.

Sakoose historically produced gold at grades of approximately 15 g/t Au from only a small portion of a structure that may extend for more than 1.4 kilometres. Historical mining, drilling and geological studies indicate that the system remains open along strike and down plunge.

With our permit application now advancing through the consultation process, we look forward to testing this opportunity through drilling."

 

 

 

 

FIGURES

Figure 1. Regional Martello map showing Tabor and Sakoose within the broader project area.

Figure 2. Regional Martello map showing principal interpreted structures within the broader project area.

Figure 3. Sakoose detail map showing the historic workings and five subordinate prospecting targets identified around the Sakoose area.

Figure 4. Plan view of the 2026 Tabor drill programme showing the relationship between the 2026 drill holes and historical drilling. Only TB-26-001 and TB-26-002 directly targeted the historically recognised high-grade core; TB-26-003 to TB-26-007 were step-out holes or geological tests.

Figure 5. Visible gold observed within quartz veining in drill hole TB-26-002 at approximately 162m.

QUALIFIED PERSON

The technical information contained in this announcement has been reviewed and approved by Sheldon Modeland, P.Geo., a director of the Company and a current member of the Association of Professional Engineers and Geoscientists of Saskatchewan (APEGS). Mr. Modeland acts as the Qualified Person for the purposes of the AIM Rules for Companies - Note for Mining and Oil & Gas Companies.

Forward Looking Statements

This announcement contains forward-looking statements relating to expected or anticipated future events and anticipated results that are forward-looking in nature and, as a result, are subject to certain risks and uncertainties, such as general economic, market and business conditions, competition for qualified staff, the regulatory process and actions, technical issues, new legislation, uncertainties resulting from potential delays or changes in plans, uncertainties resulting from working in a new political jurisdiction, uncertainties regarding the results of exploration, uncertainties regarding the timing and granting of prospecting rights, uncertainties regarding the Company's ability to execute and implement future plans, and the occurrence of unexpected events.   Actual results achieved may vary from the information provided herein as a result of numerous known and unknown risks and uncertainties and other factors.  

This announcement contains inside information for the purposes of the UK Market Abuse Regulation and the Directors of the Company are responsible for the release of this announcement.

For further information, please contact:

Richmond Hill Resources Hamish Harris	Tel: [phone]
Cairn Financial Advisers LLP (Nominated Adviser) Ludovico Lazzaretti / James Western	Tel: [phone]
Clear Capital Limited (Broker) Bob Roberts	Tel: [phone]

 

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