Selta Project –exploration update

18 December 2025

First Development Resources plc

('First Development", "FDR" or the "Company')

Selta Project -exploration update

First Development Resources plc (AIM: FDR), the UK-based, Australia-focused exploration company with mineral interests in Western Australia and the Northern Territory, is pleased to provide an update on its gold ("Au") focussed exploration at the Selta Project ("Selta" or the "Project"), located in the Aileron Province of Australia's Northern Territory.

HIGHLIGHTS

·   High-resolution aeromagnetic ("AMAG") and radiometric geophysics survey now scheduled for early January 2026, to be flown over the prospective Lander West Gold Target.

·   AMAG survey designed to map key structural features and hydrothermal alteration zones within the bedrock to enhance interpretation of potential gold-mineralised trends and controlling structures.

·   Results will directly inform and refine drill targeting, supporting efficient prioritisation of high-potential gold targets.

·   First-pass rare-earth element ("REE") sampling programme focused on two priority REE target areas, Ingallan and West Nintabirnna, at the Selta Project was successfully completed earlier this month.

·   Samples have now been submitted for laboratory analysis and further updates will be provided once results are received and assessed.

Tristan Pottas, Chief Executive Officer of FDR, commented: 

"Our recently completed targeting study has outlined multiple compelling targets along the regionally significant Stafford Gold Trend, an emerging mineralised corridor that hosts gold and high-grade antimony to the south. We believe the same structural controls extend onto the Selta Project, highlighting the potential for meaningful discovery.

The upcoming AMAG geophysics survey represents an efficient, high-impact step forward. The data will enhance our understanding of the regional structures and enable us to refine and prioritise potential drill-ready gold targets.

We are pleased to be working with Thomson Airborne to deliver this important phase of exploration."

SELTA GOLD TARGETS

Following multiple phases of detailed desktop review, the Company has identified two priority gold target areas at Selta: Lander West and Yundurbulu. The locations of these targets, along with other exploration areas on the Selta Project, are shown in Figure 1.

Notes: LCT-PEG = lithium, caesium, and tantalum (LCT) pegmatite (PEG)

Figure 1: Selta Project Targets Identified by Data Review

The potential for gold at both Lander West and Yundurbulu has been further validated by a comprehensive gold targeting study conducted by Perth-based consultants Resource Potentials earlier this year. Commissioned by FDR, the study involved compiling, re-processing, and integrating historical drilling, geological, geophysical, and geochemical datasets to pinpoint gold targets and provide recommendations for future exploration work. The findings were announced on 20 October 2025 and can be accessed via the following link:

Selta Project - Gold exploration strategy - 07:00:09 20 Oct 2025 - FDR News article | London Stock Exchange

While Yundurbulu remains highly prospective and close to known mineralisation, initial exploration will focus on the Lander West gold Target, interpreted as a continuation of the Stafford Gold Trend where iTech Minerals Ltd. (ASX: ITM) has delineated high grade gold and antimony on adjacent ground.¹

Gold targets within this corridor are interpreted to be shear-hosted, forming along zones of deformation where rocks have been sheared, altered, or brecciated. These structures often produce subtle, detectable variations in magnetic susceptibility, either from magnetite destruction during alteration or from magnetite enrichment associated with intrusions or shear-related fabrics. Determining these structures is key to identifying areas for further exploration.

A high-resolution magnetic geophysics survey across the Lander West Target will provide critical data to evaluate the structural setting and refine target potential, guiding the planning of follow-up drilling.

SURVEY METHODOLOGY AND PARAMETERS

FDR has appointed Thomson Airborne Pty Ltd ("Thomson"), a leading airborne geophysical consultancy based in New South Wales, Australia, to undertake the AMAG survey. Established in 2007, Thomson has an extensive track record delivering high-resolution magnetic and radiometric datasets for exploration companies and government agencies, including the Australian Federal Government.

The fixed-wing survey will be flown on 30° northeast-oriented lines, with 50-metre line spacing and 500-metre tie lines, using a Geometrics G823-A caesium-vapour magnetometer. The system records 20 readings per second, providing an average sample spacing of 3-4 metres along line.

A radiometric survey will be conducted concurrently as a low-cost add-on, using a Radiation Solutions RS-500w spectrometer, recording potassium, uranium, and thorium at two readings per second. This produces an average sample spacing of 30-40 metres along line and is designed to map potassium concentrations, an element associated with potassic alteration in gold deposits, such as muscovite, sericite, illite, and feldspar.

These high-resolution datasets will allow FDR's technical team to accurately delineate geological structures and alteration. FDR plans to also utilise the high-resolution magnetics data for three-dimensional inversion modelling which will further facilitate structural interpretation to depth, and help develop well-constrained targets for follow-up exploration. The 30° survey orientation intersects the regional geological fabric at approximately 90° (Figure 2), enhancing magnetic contrast across key fault structures, improving anomaly clarity, and enabling precise mapping of shape, width, and continuity of prospective shear zones.

Identifying these structures will guide targeted exploration in future phases, ensuring a cost-effective and results-driven approach on the Lander West Gold Target.

Figure 2: Proposed Survey Area with Interpreted Geology in Relation to High-Grade Au & Sb Rock chip Assays on Neighbouring Ground ¹

NEXT STEPS

The AMAG survey represents the first step in a multi-phase exploration strategy, designed to systematically advance high-priority gold targets to a drill-ready stage. This approach will provide FDR's technical team with critical structural and geophysical data, enabling more precise targeting and increasing the potential for significant gold discoveries, while maintaining a cost-effective exploration programme.

SELTA RARE-EARTH ELEMENT EXPLORATION UPDATE

The Company is pleased to advise that the previously announced first-pass rare-earth element ("REE") sampling programme at the Selta Project was successfully completed earlier this month. The original announcement dated 19 November 2025 is available via the link below.

Selta Project - REE Exploration Update - 07:00:04 19 Nov 2025 - FDR News article | London Stock Exchange

The programme focused on two priority REE target areas, Ingallan and West Nintabrinna, which were identified following detailed desktop studies. Field activities were designed to validate historical geochemical anomalies and to generate additional targets for potential follow-up mapping, sampling and investigation of ionic clay-hosted REE potential at Ingallan.

Samples collected from both the Ingallan and West Nintabrinna target areas have now been submitted for laboratory analysis. The Company will provide further updates once results are received and assessed.

REFERENCE

1.     iTech Minerals Ltd (ASX: ITM) announcement dated 19 August 2025
( https://announcements.asx.com.au/asxpdf/20250819/pdf/06n0xk4zmh438y.pdf )

QUALIFIED PERSON STATEMENT

The technical information contained in this disclosure has been reviewed and approved by Mr Nicholas O'Reilly (MSc, DIC, MIMMM QMR, MAusIMM, FGS), who is a qualified geologist and acts as the Qualified Person under the AIM Rules - Note for Mining and Oil & Gas Companies. Mr O'Reilly is a principal consultant working for Mining Analyst Consulting Ltd which has been retained by First Development Resources plc to provide technical support.

GLOSSARY

For further information visit www.firstdevelopmentresources.com or contact the following:

Beaumont Cornish Limited ("Beaumont Cornish") is the Company's Nominated Adviser and is authorised and regulated by the FCA. Beaumont Cornish's responsibilities as the Company's Nominated Adviser, including a responsibility to advise and guide the Company on its responsibilities under the AIM Rules for Companies and AIM Rules for Nominated Advisers, are owed solely to the London Stock Exchange. Beaumont Cornish is not acting for and will not be responsible to any other persons for providing protections afforded to customers of Beaumont Cornish nor for advising them in relation to the proposed arrangements described in this announcement or any matter referred to in it.

ABOUT FIRST DEVELOPMENT RESOURCES

First Development Resources' assets comprise eight granted tenements covering a total area of 2,314.4km². Five of the tenements, comprising three prospective copper-gold projects, are located in Western Australia (WA) while the remaining three tenements, comprising a rare-earth element (REE), uranium, lithium and gold project, are located in the Australian's Northern Territory. All tenements are wholly owned by FDR. The assets are a mixture of drill ready and earlier stage exploration.

The WA Projects include the Company's Wallal Project as well as Ripon Hills and Braeside West Projects situated in the Paterson Province, which is widely regarded as one of the most productive regions in Australia for the discovery of world-class gold-copper deposits, and which is home to several world-class mines and more recent discoveries.

The Selta Project in the Northern Territory is located in an area considered highly prospective for uranium and rare-earth element mineralisation along with base and precious metal mineralisation. Numerous companies are actively exploring within the region.

Beyond the existing portfolio, FDR is actively looking to expand its portfolio through the acquisition of early-stage exploration projects in Australia.