This announcement contains inside information for the purposes of Regulation 11 of the Market Abuse (Amendment) (EU Exit) Regulations 2019/310. With the publication of this announcement via a Regulatory Information Service, this inside information is now considered to be in the public domain.

2 September 2026

Rome Resources plc

("Rome Resources" or the "Company")

45% increase in contained tin at Kalayi

and

High-grade updated MRE confirmed with potential substantial exploration upside

Rome Resources plc (AIM: RMR), the DRC focused critical minerals explorer, is pleased to announce the publication of an updated mineral resource estimate ("MRE") for its Kalayi tin deposit at the Bisie North Project in the Democratic Republic of Congo.

The updated Inferred MRE comprises 0.46 million tonnes at 1.47% tin ("Sn"), containing 6.76 thousand tonnes of tin at a 0.80% Sn cut-off grade. Compared with the maiden MRE published by the Company on 30 October 2025 (the "October 2025 MRE") on the same cut-off basis, this represents a 45% increase in contained tin, a 32% increase in resource tonnage and a 10% increase in average grade - representing resource growth achieved without grade dilution.

The updated MRE was prepared by The MSA Group (Pty) Ltd ("MSA") in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Best Practice Guidelines and reported in accordance with the 2014 CIM Definition Standards for Mineral Resources & Mineral Reserves. The full unedited CIM compliant updated MRE is available for viewing at:

http://www.rns-pdf.londonstockexchange.com/rns/9913S_1-2026-9-1.pdf

MSA have also defined an area immediately southeast of the updated MRE, lying along strike from the existing high-grade resource and, subject to further drilling, represents potential for doubling the resource estimate.

Highlights

·      Updated Inferred MRE: 0.46 Mt @ 1.47% Sn containing 6.8 kt tin at 0.80% Sn cut-off - representing a 45% increase in contained tin versus the October 2025 MRE on a like-for-like basis

·      Resource growth achieved without grade dilution: both tonnage (+32%) and grade (+10%) have increased simultaneously, from 1.33% to 1.47% Sn

·      MSA has defined an area immediately southeast of the updated MRE along the high-grade tin trend. Subject to further drilling, this represents an opportunity to double the resource potential

·      MSA's updated geological model now comprises 11 mineralised zones (MINZ1-11), up from 7 in 2025, demonstrating the growing scale of the Kalayi deposit

·      MINZ8 and MINZ9, identified in the 20 August 2026 technical update, are insufficiently constrained by current drilling density for inclusion in the updated MRE and represents further resource growth potential within the existing deposit footprint

·      Mont Agoma: a separate polymetallic system within Bisie North with a maiden resource of 3.16 Mt at 1.45% Cu, 2.72% Zn and 14.3 g/t Ag, with defined high-priority tin and copper targets largely undrilled

·      Rome Resources continues to engage with potential strategic parties regarding the advancement and development of the Bisie North Project

Paul Barrett, Chief Executive Officer of Rome Resources, commented:

"I am delighted with Kalayi's direction of travel. This is a genuinely high-grade tin deposit, and objectively, is getting better. The numbers that matter the most are not just the 45% increase in contained tin, it is also that both tonnage and grade have increased simultaneously, from 1.33% to 1.47% Sn. In the Board's view, resource growth without grade dilution is unusual and reflects improving geological confidence. At 2026 tin prices, we believe that the margin potential of a deposit at this grade, less than 10 km from established tin ore processing infrastructure, is compelling.

Kalayi is only part of the Bisie North story. Mont Agoma is a separate and substantial polymetallic system with its own maiden resource of copper, tin and zinc. With copper prices at record highs, the polymetallic optionality Mont Agoma offers is increasingly significant and the undrilled southeast tin and northwest copper targets represents upside the current resource does not yet reflect.

Kalayi's own upside is equally compelling: an area immediately southeast along the same high-grade trend has the potential for doubling the currently defined resource.  Furthermore, mineral zones 8 and 9 are open at depth and require further penetrations to book as additional resource. In the Board's view, the picture emerging at Bisie North, across both assets, is of a growing, multi-commodity critical minerals opportunity in the world's highest-grade tin district.

Bisie North's growing resource base, with 20 kt of contained tin being a realistic, combined target going forward and its strategic location, continues to attract attention. We look forward to updating shareholders as the project advances."

Updated Mineral Resource Estimate

Table 1.  Comparative tin tonnages and grades for the 2025 and 2026 Kalayi MRE's

The updated MRE reflects a materially improved geological model developed by MSA following incorporation of results from the 2026 drilling campaign. The model now comprises 11 discrete mineralised zones (MINZ1-11), compared with seven zones in the 2025 model, reflecting the growing understanding of Kalayi's vein system and the identification of additional mineralised intervals during the latest programme.

Critically, the resource expansion has not been achieved through grade dilution. Both tonnage and grade have increased simultaneously with resource tonnage rising 32% from 0.35 Mt to 0.46 Mt, and average grade increasing 10% from 1.33% Sn to 1.47% Sn at the 0.80% cut-off. The Company believes that this reflects the improved geological continuity demonstrated by the wider mineralised intercepts from the 2026 campaign, particularly the broader zones encountered in drill holes KBDD025, KBDD033 and KBDD034.

Figure 2.  Kalayi block model showing MZ4 grades.  Red is above 2% Sn.

The updated model confirms that mineralisation remains open along strike, particularly to the southeast, and at depth, providing the foundation for the exploration target defined by MSA and described in the following section.

Significant exploration upside beyond the current MRE

Southeast Kalayi area

MSA has identified further potential mineralisation zones immediately southeast of the current Kalayi resource. The target lies along the same high-grade tin trend as the current resource and reflects the interpreted continuation of mineralisation beyond the current drilling footprint. Further drilling provides the opportunity to identify an area that could double the quantity of Mineral Resource.  It should be noted that the results of the exploration programme are not guaranteed to either intersect tin mineralisation or result in additional Mineral Resources.

MINZ8 and MINZ9

As disclosed on 20 August 2026, MSA identified two additional mineralised zones, MINZ8 and MINZ9, supported by intercepts from drill hole KBDD033. These zones are insufficiently constrained for inclusion in the updated MRE and will require further drilling to establish continuity. They represent additional resource growth potential within the existing Kalayi deposit footprint, separate from the southeast exploration target.

Mont Agoma and wider Bisie North potential

Kalayi is one of two advanced targets within the Bisie North licence package. Mont Agoma is a separate and substantial polymetallic system with a maiden Inferred Resource of 3.16 million tonnes at 1.45% copper, 2.72% zinc, 0.19% tin and 14.3 g/t silver. Drilling has demonstrated that tin grades strengthen with depth, consistent with analogous systems including Alphamin's Bisie mine and Minsur's San Rafael deposit in Peru.

As announced in February 2026, Chemostrat's geological interpretation identified a largely undrilled zone of elevated tin prospectivity southeast of the existing Mont Agoma deposit, as well as a prospective copper target extending to the northwest. With copper at record highs, the polymetallic optionality and resource upside that Mont Agoma offers is increasingly significant.

It is anticipated the interpretation of the airborne geophysics data will be completed by the end of September 2026, and this may additionally direct efforts to further potential on the licences.

Bisie North growth opportunity

Strategic Positioning of Bisie North

With an updated high-grade resource confirmed, substantial exploration upside defined, and pilot mining advancing towards a full mining licence, Rome Resources will continue discussions with potential strategic parties regarding the advancement and development of the Bisie North project.

Tin market context

Tin is currently trading at approximately $50,000 per tonne, significantly above the $36,600 per tonne assumed in the October 2025 MRE economic parameters. The tin market continues to be characterised by a structural supply deficit, with few new high-grade deposits in development globally and existing producers facing declining grades and reserve depletion.

Against this backdrop, Kalayi's confirmed average grade of 1.47% Sn places it amongst a very small number of deposits worldwide capable of generating compelling project economics at any point in the tin price cycle. Mont Agoma adds further optionality, with copper also trading at or near record highs.

**ENDS**

Subscribe to our news alert service: https://romeresources.com/auth/signup

This Announcement is made in accordance with the Company's obligations under Article 17 of UK MAR and the person responsible for arranging for the release of this Announcement on behalf of Rome Resources is Paul Barrett, Chief Executive Officer.   

Qualified Person Statement

Dr Deon Vermaakt is a consultant of Rome Resources plc, a qualified geologist and a registered Professional Natural Scientist (Geological Science) with the South African Council for Natural Scientific Professions (SACNASP Reg. No. 400020/00). Dr Vermaakt is a qualified person (QP) under NI 43-101 and as defined by the AIM Note for Mining, Oil and Gas Companies and has reviewed and approved the scientific and technical information contained in this news release.

Glossary of abbreviations

Glossary of technical terminology