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15 September 2026

First Development Resources plc

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

Selta Project: Lander West Drilling Confirms Gold

Bedrock Gold Confirmation Launches Next Exploration Phase

First Development Resources plc (AIM: FDR), the Australian-focused exploration company, is pleased to report assay results from its initial Reverse Circulation ("RC") drilling programme at the Lander West gold ("Au") target within the Selta Project in the Northern Territory.

The eight-hole, 1,593 metre programme has confirmed primary gold (Au) mineralisation in bedrock at Lander West. Hole 26LWR08 returned 7m @ 0.40 g/t Au from 50m downhole, including 2m @ 0.98 g/t Au, with a peak 1m assay of 1.11 g/t Au. Au anomalism was encountered in six of the eight holes.

Importantly, the drilling has provided FDR with significant new geological information which, when integrated with surface geochemistry, modern geophysics and the reconstructed historical exploration dataset, has materially advanced the Company's understanding of Lander West. Multiple priority targets have now been identified across a large target area where significant gaps remain between historical drill fences and across prospective magnetic and structural features. The Company is finalising the next phase of exploration, with preparations underway and field crews expected to return to Lander West in October.

HIGHLIGHTS

·    Red Handed gold mineralisation: Drillhole 26LWR08 returned 7m @ 0.40 g/t Au from 50m downhole, including 2m @ 0.98 g/t Au; validation of historical RAB drilling data (Normandy NFM Ltd, 1995-1998), has also confirmed historical hole RHB108 returned 16m @ 0.30 g/t Au from 12m, including 2m @ 1.93 g/t Au.

·    Au anomalism encountered in six of eight RC holes, providing additional evidence of hydrothermal activity and geological vectors for follow-up across Lander West.

·    Copper (Cu) mineralisation intersected: Drillhole 26LWR02 returned 8m @ 0.32% Cu from 47m downhole, including 5m @ 0.39% Cu, with a peak 1m assay of 0.58% Cu.

·    Multiple priority targets identified: integrated drilling, geophysics, surface geochemistry and historical data review have defined a pipeline of priority exploration areas across Lander West, referred to by the Company as the Red Handed, Red Hackle, Auraria, L1 and Giles areas (Figure 2).

·    Next exploration phase being finalised: preparations have commenced, with field crews expected to return to Lander West in October and work directed towards ranking and refining targets for subsequent Aircore ("AC") and RC drilling.

Tristan Pottas, Chief Executive Officer, commented:

"Exploration is a systematic and iterative process, and I believe we have made a very solid start at Lander West. Our initial programme has confirmed something fundamental - we are exploring a genuine gold-bearing system.

"By bringing together our drilling, surface geochemistry, modern geophysics and the reconstructed historical dataset, we now have a significantly stronger understanding of that system and, importantly, where we should be looking next.

"There is clearly more work to do. We have established that the system carries gold and we now have multiple targets and a much stronger integrated dataset to guide us. The objective is simple: find where this Au-bearing system delivers better grade, width and continuity. I am excited about the next phase of exploration at Lander West."

INITIAL RC DRILLING

The initial programme comprised eight RC holes for 1,593 metres across geological, geochemical and geophysical targets at Lander West.

At Red Handed, drillhole 26LWR08 intersected 7m @ 0.40 g/t Au from 50m downhole, including 2m @ 0.98 g/t Au, with a peak 1m assay of 1.11 g/t Au. The strongest Au response occurs within sulphide-bearing dolerite. When compared with historical drilling and magnetic data, this provides FDR with a potential geological vector that can now be tested elsewhere across Lander West.

Au anomalism was also encountered in several other holes, including peak assays of 0.385 g/t Au in 26LWR01 and 0.221 g/t Au in 26LWR03, supporting evidence of widespread hydrothermal activity across the project.

Separately, drillhole 26LWR02 intersected 8m @ 0.32% Cu from 47m downhole, including 5m @ 0.39% Cu, with a peak 1m assay of 0.58% Cu. The significance of this copper mineralisation is being assessed within the broader mineralising system.

SURFACE EXPLORATION AND ROCK-CHIP GEOCHEMISTRY

FDR's 2026 geological reconnaissance and rock-chip sampling programme recorded 243 samples/sites across Lander West. Au values reached 0.64 g/t Au, with associated pathfinder geochemistry including elevated As, W, Sb, Bi and Cu.

The rock-chip assay results provide additional evidence of hydrothermal activity across the wider target area and, together with the RC drilling and geophysical datasets, are helping FDR prioritise areas for follow-up.

Figure 1: Detailed Red Handed target plan showing FDR's 2026 RC drilling, historical RAB and vacuum drilling, interpreted dolerite and structural features, and the location of the historical RHB108 and FDR 26LWR08 Au intersections.

HISTORICAL DATA REVIEW HIGHLIGHTS EXPLORATION GAPS

FDR's reconstruction and validation of the historical exploration dataset has materially advanced the Company's understanding of Lander West. Much of the historical drilling was shallow, with significant gaps between drill fences and across prospective magnetic and structural features. When considered against the scale of Lander West, the Company believes substantial prospective areas remain insufficiently tested by systematic modern exploration.

At Red Handed, FDR's review has validated historical RAB hole RHB108 (drilled 4 September 1997), reported by Normandy NFM Ltd, as returning 16m @ 0.30 g/t Au from 12m, including 2m @ 1.93 g/t Au. The higher-grade interval was subsequently re-assayed by fire assay with an Atomic Absorption Spectroscopy ("AAS") finish. ^* Whilst RHB108 and FDR's 26LWR08 occur at separate locations 834m apart, and do not demonstrate continuity, they both provide further evidence of an Au-bearing system at Red Handed, which strengthens the rationale for systematic follow-up.

* Source: GMIS file CR1999-0184: Normandy NFM Ltd, Final Report for Red Hackle EL 8367 for the period 20 April 1994 to 25 January 1999, dated April 1999 ( https://www.geoscience.nt.gov.au/gemis/ntgsjspui/handle/1/64056 )

The integrated review has identified a pipeline of targets at different stages of maturity. Red Handed is the immediate priority, followed by Red Hackle, Auraria, L1 and Giles. Follow-up at Red Handed will test whether mineralisation can be traced along strike and at depth and, critically, whether grade, width and continuity improve.

Figure 2: Integrated Lander West target plan showing FDR's 2026 RC drilling, historical drilling, airborne magnetic data, interpreted structural features and the principal priority exploration areas identified for follow-up.

NEXT PHASE - EXPLORATION CONTINUES IN OCTOBER

The Company is finalising the next phase of exploration, with field crews expected to return to Lander West in October. Work will focus on advancing and refining the priority targets identified through the integrated review, with results used to rank opportunities for subsequent AC and RC drilling.

The programme will be staged and capital-disciplined, with targets required to earn further expenditure. Red Handed is the immediate priority, alongside Auraria, L1 and Red Hackle. The objective is to determine whether the Au-bearing system demonstrated at Lander West develops into zones of materially better grade, width and continuity.

KEY DOWNHOLE DEPTH DRILL INTERSECTIONS

INITIAL RC DRILL-HOLE COLLAR DETAILS

Total drilled: 1,593m. Projection: UTM Zone 53S MGA94 Datum. Azimuth relative to true north (T).

GLOSSARY

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.

The information communicated within this announcement is deemed to constitute inside information as stipulated under the Market Abuse Regulations (EU) No 596/2014 which is part of UK law by virtue of the European Union (Withdrawal) Act 2018. Upon publication of this announcement, this inside information is now considered to be in the public domain.

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 (AIM: FDR) is a UK-based, Australian-focused exploration company advancing mineral exploration projects in the Northern Territory and Western Australia. Its principal exploration focus is the 100%-owned Selta Project in the Northern Territory, where initial RC drilling at Lander West has confirmed primary bedrock Au mineralisation and the Company is advancing a staged follow-up exploration programme.

FDR also maintains interests in Western Australia, including the Wallal Project in the Paterson Province, while actively managing its wider portfolio in accordance with its strategy of disciplined capital allocation.