Increased Ore Reserve and Improved Economics

Halo Minerals plc (AIM: HALO), the copper development company focused on recovering critical minerals from legacy mining waste, announces an updated Competent Person’s Report (“CPR”) for its Playa Verde copper tailings project in Chile. The CPR increases the Ore Reserve by 5.4% to 33.94 Mt and, on the Ore Reserve alone, supports an after-tax NPV10 of US$174.3 million and an after-tax IRR of approximately 46%.

Key highlights

Ore Reserves increased by 1.74 Mt, or approximately 5.4%, to 33.94 Mt at 0.25% Cu, containing 83,626 tonnes of in-situ fine copper.

The Ore Reserve base case produces an after-tax NPV10 of US$174.3 million and an after-tax IRR of 45.6% with project level average annual free cashflows of US$56 million.

Total Mineral Resources are 53.44 Mt at 0.24% Cu, inclusive of Ore Reserves, containing 127,911 tonnes of in-situ fine copper.

A separate full-resource management case, using the full 53.44 Mt onshore Mineral Resource, produces an after-tax NPV10 of US$267.5 million and an after-tax IRR of 48%.

Identified CAPEX and reagent-cost optimisation increases the after-tax NPV10 to US$190.6 million for the Ore Reserve case and US$295.5 million for the full-resource management case.

EMI identifies preliminary potential to increase Ore Reserves by approximately 25% to 30% in the short term, subject to further technical work and confirmation of modifying factors.

The CPR was prepared by EMI-Ingenieros y Consultores S.A. (“EMI”). It incorporates the 2026 basic engineering update and Class 3 capital and operating cost estimates prepared by BIOS Mining & Infrastructure, together with updated Mineral Resource and Ore Reserve classifications. The Mineral Resource and Ore Reserve estimates are reported in accordance with the JORC Code (2012).

Economic cases at a glance

The cases below are presented separately so that the current Ore Reserve economics are not confused with management assumptions or potential future upside.

Andrew Dennan, Chief Executive Officer of Halo Minerals, commented:

“The updated CPR provides an independent reassessment of Playa Verde. The declared Ore Reserve has increased to 33.94 million tonnes and, on that Ore Reserve alone, the updated work supports an after-tax NPV10 of US$174.3 million and an after-tax IRR of approximately 46%.

“The CPR also sets out the potential beyond the current Ore Reserve. This includes the wider onshore Mineral Resource, identified capital and operating cost improvements, and the potential to convert further resources into reserves. These costed opportunities demonstrate the potential to deliver a project NPV10 in the orders of magnitude of around $300 million. The project also has a longer-term ambition to incorporate the surf and bay zones, which host the potential to significantly increase the project resource base, and will be modelled at an appropriate time in the future.

“With the updated technical work substantially advanced, Halo is focused on completing the remaining optimisation, commercial and financing work required to progress Playa Verde towards a final investment decision.”

Mineral Resources and Ore Reserves

The updated statement is summarised below. Mineral Resources are inclusive of Ore Reserves and must not be added to them.

Mineral Resources and Mineral Reserves Statement 2026 Update

Summary of Reserves and Resources by Categorisation

The September 2026 recategorisation incorporated an additional 1.74 Mt of Measured and Indicated Resources into the extraction plan without changing the deposit geometry or mine-plan envelope. This increased Ore Reserves by approximately 5.4%.

Ore Reserve base case

The principal economic assessment is based on the declared Ore Reserve of 33.94 Mt only. It uses a 10% discount rate and the assumptions and results below.

The sensitivity analysis indicates that project economics are most sensitive to copper price, copper recovery and operating costs.

Production programme

The production programme assumes a consolidated extraction and processing rate of approximately 5.0 Mtpa and an initial operating period of seven years. The current schedule sends approximately 34.8 Mt to the plant, comprising the declared Ore Reserve and approximately 0.86 Mt of Inferred Resource. The 0.86 Mt of Inferred Resource is not included in the declared Ore Reserve or in the Ore Reserve economic case summarised above.

Capital and operating costs

The 2026 Class 3 engineering update, authored by BIOS Mining and Infrastructure (“BIOS MI”) as announced by the Company on 28 September 2026, estimates initial project capital expenditure of US$92.8 million, excluding VAT. The estimate assumes a third-party dredging service model, under which dredging equipment is treated as an operating cost rather than initial capital expenditure. BIOS MI has also noted the opportunity to reduce initial CAPEX by US$6 to 10 million via value engineering and competitive procurement tendering processes which would represent an upside for the Company to capture versus the below analysis.

Base-case operating costs are estimated at approximately US$2.20/lb of copper produced and marketed. Sulphuric acid is the dominant reagent cost. The base case assumes US$200/t; BIOS MI has identified potential to reduce this to US$150/t through a long-term supply contract.

Potential reserve growth and further upside

EMI considers that the geometry and mineralogical continuity of the artificial tailings deposit indicate potential, on a preliminary basis, to increase Ore Reserves in the short term by approximately 25% to 30%. This is subject to statistical review, infill drilling, block-model updating, resource recategorisation and confirmation of the relevant modifying factors. On that basis, potential Ore Reserves could increase to approximately 42.4 Mt to 44.1 Mt.

The current JORC Mineral Resource covers the beach area only. Historical subsea drilling and bathymetry indicate additional mineralised tailings in the surf and bay zones, subject to further exploration, sampling and regulatory approvals.

Further NPV upside of approximately US$4.4 million may be available through optimisation of the dredging starting point and extraction sequence, subject to operational and community constraints.

Ore processing and extraction

The process route combines acid leaching, solvent extraction and electrowinning with flotation. Weathering and oxidation have converted a substantial proportion of the copper into acid-soluble oxides and chlorides, while the sulphide component is recovered through flotation. The combined flowsheet has an estimated overall copper recovery of approximately 72%.

Tailings extraction is planned by dredging, using an electric dredging wheel in a controlled multi-lane pond. Reprocessed tailings are intended to be redeposited behind the advancing dredging operation. The design reflects the non-cohesive nature of the tailings and is intended to balance technical feasibility, operating continuity and cost control.

Qualified Person

The information in this announcement relating to Mineral Resources, Ore Reserves, mine planning, metallurgy and economic evaluation for the Playa Verde Copper Tailings Project is extracted from the updated CPR prepared for Halo Minerals PLC by EMI-Ingenieros y Consultores S.A., dated 15 October 2026. EMI is an independent Chilean mining engineering and consulting firm with experience in resource and reserve audits and feasibility-level studies.

The CPR was compiled under the supervision of Mr Orlando Rojas Vercelotti, Civil Mining Engineer, a Competent Person as defined in the JORC Code (2012) and acts as a Qualified Person under the AIM Rules - Note for Mining, Oil & Gas Companies, who has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken.

Mr Rojas Vercelotti has reviewed the information contained in this announcement, to the extent that it relates to matters summarised from the CPR, and has consented to the inclusion of such information in the form and context in which it appears.

The Directors of the Company are responsible for the release of this announcement.

Competent Person (CP) – Individual responsible for the technical report who meets experience, competence and professional membership requirements.

CPR – Competent Person Report.

CRM – Certified Reference Material.

Exploration Target (JORC 2012) – Statement of exploration potential expressed as ranges of tonnes and grade where insufficient information exists to estimate a Mineral Resource.

IP – Induced Polarisation.

M&I Resources – Measured and Indicated Resources.

QA/QC – Quality Assurance / Quality Control. RC – Reverse Circulation drilling.

Units, Symbols and Financial Abbreviations

Metric Units

t – Metric tonne (1,000 kg) kt / Kton – Thousand tonnes

Mt – Million tonnes

%Cu – Copper grade by weight

Imperial / U.S. Customary Units

oz (troy) – 31.1035 g lb – 0.453592 kg short ton (st) – 907.185 kg

long tonne (lt) – 1,016.05 kg Financial

US$ – United States dollars

K US$ – Thousand U.S. dollars

M US$ / US$M / Mill US$ – Million U.S. dollars

CAPEX – Capital Expenditure

OPEX – Operating Expenditure

AIM (Alternative Investment Market) Terminology

AIM – Growth market of the London Stock Exchange

AIM Rules – Regulatory framework for AIM-listed companies

AIM Admission Document – Required disclosure for listing

AIM Nomad – Nominated Adviser ensuring compliance

AIM-listed Company – Company admitted to AIM