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3 August 2026

First Development Resources plc

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

Completion of Phase I RC Drilling at Lander West

First Development Resources plc ("FDR" or the "Company"), the Australia-focused exploration company, is pleased to announce the completion of the first stage of the Phase I reverse circulation ("RC") drilling programme, announced on 13 July 2026, at the Lander West Prospect within the wholly owned Selta Project in the Northern Territory, Australia.

The work completed to date comprises eight RC drill holes for a total of 1,593 metres drilled, detailed geological mapping and the collection of 243 rock-chip samples from across the southern part of the prospect. All drill and rock-chip samples have now been dispatched to ALS Geochemistry in Adelaide for laboratory analysis.

HIGHLIGHTS

·    First stage of Phase I RC drilling programme completed with 1,593 metres drilled across eight holes.

·    243 rock-chip samples collected as part of an extensive geological mapping and reconnaissance programme.

·   Drilling, geological mapping and rock-chip sampling have significantly improved the Company's understanding of the geology at Lander West.

·    Multiple pegmatite intervals, quartz veining and alteration were intersected within the southern target area.

·    Drilling of the northern magnetic geophysics anomaly intersected mafic rocks and sulphide-bearing intervals, indicating a distinct geological setting.

·    Assay results will be integrated with geological and geophysical datasets to refine the geological model and prioritise the next stage of exploration.

Tristan Pottas, Chief Executive Officer of FDR, commented:

"The completion of this maiden Phase I drilling represents an important milestone for First Development Resources, marking the first programme to systematically test our priority exploration targets at depth at Lander West.

Whilst assay results remain outstanding, the programme has significantly improved our understanding of the project's geology and provided a much stronger framework from which to plan future exploration once assay results are received."

PROGRAMME SUMMARY

The Phase I RC drilling programme was designed to test priority geophysical and geological targets identified through airborne magnetic geophysical surveys, Gradient Array Induced Polarisation ("GAIP") geophysics and surface geochemistry.

As announced on 13 July 2026 the total Phase I programme was designed to comprise up to 3,000 metres of RC drilling to be completed in stages, with the results and observations from initial holes to inform subsequent targeting.  In the completed first stage of work, a total of 1,593 metres have been drilled across eight RC drill holes (see Table 1 and Figure 1). In parallel, the Company completed detailed geological mapping and collected 243 rock-chip samples targeting pegmatite outcrop, quartz veins and alteration.

The work to date has successfully achieved the primary exploration objectives of the Phase I programme, with all planned priority target areas tested despite the occasional operational challenges extending the drilling time.

Southern Target Area

Six drill holes tested coincident magnetic, chargeability and geochemical anomalies associated with interpreted structural features in the southern part of the prospect.

Drilling intersected multiple pegmatite intervals together with abundant quartz veining, alteration and a range of metasedimentary and mafic lithologies. Geological reconnaissance also identified extensive pegmatite outcrop extending beyond the immediate drill area.

The combination of drilling, geological mapping and systematic rock-chip sampling has materially refined the Company's understanding of the geological architecture of the southern target area.

Although several lithological and structural features capable of generating the observed geophysical and geochemical responses were encountered, the source of the southern magnetic anomaly has not yet been conclusively identified.

Northern Target Area

Two drill holes tested a separate magnetic anomaly in the northern part of the Lander West Prospect.

Drilling intersected metasedimentary and mafic rocks, including localised sulphide-bearing intervals, indicating that this area represents a distinct geological setting from the southern target area. Whilst these sulphide-bearing lithologies may provide a potential explanation for the northern magnetic anomaly, this interpretation will be evaluated following receipt of assay results and integration with the Company's geological and geophysical datasets.

NEXT STEPS

Assay results from both the RC drilling and rock-chip sampling will be integrated with the geological observations and geophysical datasets to refine the geological model and determine priorities for the next stage of exploration.

The Company will provide a further update following receipt and interpretation of the assay results.

Figure 1 shows the location of the completed drill holes (Table 1) together with the principal southern and northern exploration targets at Lander West.

Figure 1: Map of Lander West Target, with Location of Completed Drill Holes, Northern and Southern Targets and Pegmatite Areas.

Table 1: Phase I Reverse Circulation Drill  Hole Details

Projection: UTM Zone 53S MGA94 Datum. Azimuth relative to true north (T).

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.

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 plc is an Australian-focused exploration company with a portfolio of wholly owned mineral exploration projects in the Northern Territory and Western Australia.

The Company's flagship Selta Project in the Northern Territory comprises three granted exploration licences prospective for lithium, rare earth elements (REE), uranium, gold and base metals. The project includes the highly prospective Lander West target, where the Company recently completed its maiden drill programme and first-ever drilling at depth.

In Western Australia, FDR retains the Wallal Project in the Paterson Province, one of Australia's premier mineral provinces and home to several world-class copper-gold deposits and significant recent discoveries.

FDR's portfolio comprises a combination of drill-ready and earlier-stage exploration assets. Beyond its existing portfolio, the Company continues to evaluate opportunities to expand its Australian exploration portfolio through the acquisition of high-quality, early-stage mineral exploration projects.

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