GREAT BOULDER RESOURCES LIMITED — Capital/Financing Update 2025

Apr 28, 2025

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ASX Announcement
29 APRIL 2025
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SHALLOW, HIGH-GRADE GOLD ZONE EXTENDED AT EAGLEHAWK

HIGHLIGHTS

• ➢ Further shallow, high-grade gold mineralisation delivered from RC drilling at Eaglehawk, confirming the exciting prospectivity of this mineralised system, with latest significant results including:

• 3m @ 8.98g/t Au from 136m, including 1m @ 20.70g/t Au from 138m in 25MBRC020

• 12m @ 2.47g/t Au from 70m, including 3m @ 5.39g/t Au from 74m in 25MBRC019

• ➢ These latest results are in addition to previously released significant results including: o 26m @ 5.15g/t Au from 79m, including 4m @ 20.50g/t Au from 92m in 25MBRC002

• 3m @ 46.70g/t Au from 139m, including 1m @ 79.50g/t Au from 140m in 25MBRC006

• ➢ These RC results are the balance of a 20-hole campaign completed at Eaglehawk, with further drilling being designed to follow up lateral and depth extensions

• ➢ Initial results from AC drilling targeting mineralisation in the dacite host unit in the area extending from Mulga Bill to Eaglehawk has intersected several additional mineralised zones, including:

• 3m @ 4.53g/t Au from 130m to End of Hole (EOH) in 25SWAC096, in the previously untested gap between Mulga Bill and Eaglehawk

• 9m @ 1.67g/t Au from 88m in 25SWAC106

• 14m @ 1.42g/t Au from 86m in 25SWAC116

• ➢ AC drilling at Eaglehawk is continuing to test and define further mineralisation in the dacite corridor to the North, with additional results expected shortly

• ➢ The Ironbark scoping study is on track for completion this quarter

Great Boulder Resources (“ Great Boulder ” or the “ Company ”) (ASX: GBR ) is pleased to provide an update on exploration at the Company’s flagship Side Well Gold Project (“ Side Well ”) near Meekatharra in Western Australia which hosts a Mineral Resource Estimate (“ MRE ”) of 668,000oz @ 2.8 g/t Au.

Great Boulder’s Managing Director, Andrew Paterson commented:

“We are continuing to build momentum at the emerging Eaglehawk deposit, using a combination of air-core (AC) drilling to refine targets followed by RC drilling to test high grades at depth. This process has been working extremely well since we defined the key dacite host unit, as announced in December 2024.”

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

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“The recent RC program at Eaglehawk and Mulga Bill has continued to successfully identify zones of high-grade gold. We’re now well into the air-core program at Eaglehawk, with initial results defining more zones of shallow gold mineralisation. All of these holes will help refine our targets for ongoing RC testing as we progress Eaglehawk towards an initial resource estimate, which will be an important step in the next stage of resource growth at Side Well.”

“It’s also worth noting the new drilling in the gap between Mulga Bill and Eaglehawk intersected 3m @ 4.53g/t Au with the hole ending in mineralisation, suggesting those two prospects may join up as we continue drilling. This is another example of this deposit continuing to deliver gold intersections from areas where we’ve not previously drilled.”

“As always, we have a lot of samples at the assay lab so I look forward to releasing more high-grade results in the coming weeks. Separately, the Ironbark scoping study is progressing well and I look forward to reporting initial results as soon as possible.”

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FIGURE 1: RECENT AC AND RC RESULTS FROM MULGA BILL & EAGLEHAWK

E: admin@greatboulder.com.au ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

GREATBOULDER.COM.AU

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Eaglehawk RC & AC Drilling

Assays from the final four RC holes from a 20-hole program at Mulga Bill and Eaglehawk have been received, with the following significant intercepts delivered from Eaglehawk:

• 3m @ 8.98g/t Au from 136m, including 1m @ 20.70g/t Au from 138m in 25MBRC020

• 12m @ 2.47g/t Au from 70m, including 3m @ 5.39g/t Au from 74m in 25MBRC019

• These new significant results are in addition to previously released significant results1 including:

• 26m @ 5.15g/t Au from 79m, including 4m @ 20.50g/t Au from 92m in 25MBRC002[2]

• 3m @ 46.70g/t Au from 139m, including 1m @ 79.50g/t Au from 140m in 25MBRC006

• 2m @ 5.40g/t Au from 137m in 25MBRC003

Eaglehawk is shaping up to be a significant new discovery which GBR has only just begun to test, with the first programs of targeted RC holes delivering multiple significant intersections of wide and high-grade mineralisation within the dacite host unit.

Mineralisation remains open laterally along strike (north and south) and also at depth. The Company is confident that further drilling to test Eaglehawk mineralisation extensions will deliver further significant intercepts with the potential to provide substantial resource additions to the Side Well Project.

48 AC holes have been drilled from the northern end of Mulga Bill through Eaglehawk, defining the most prospective dacite host unit towards the north and east. This program is due to be completed shortly. Highlights from the initial assays include:

• 3m @ 4.53g/t Au from 130m to EOH in 25SWAC096, in the gap between Mulga Bill and Eaglehawk

• 9m @ 1.67g/t Au from 88m in 25SWAC106

• 14m @ 1.42g/t Au from 86m in 25SWAC116

• 4m @ 2.56g/t Au from 76m in 25SWAC095

• 5m @ 2.10g/t Au from 94m, and 4m @ 1.11g/t Au from 104m in 25SWAC111.

Ironbark RC Drilling

Four RC holes were recently completed at Ironbark, testing a possible southerly plunge to highgrade gold mineralisation. Mineralisation at this end of the Ironbark deposit has not been closed off by previous drilling.

Assay results from this program are expected within the next three to four weeks.

1 Refer to ASX releases dated 12 March 2025 and 7 April 2025

2 The intersection in 25MBRC002 was originally reported as 29m @ 4.79g/t Au from 76m. Two 4m composite assays included in this intersection have been re-assayed as 1m samples, giving a final intersection result of 26m @ 5.15g/t Au from 79m down-hole.

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

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FIGURE 2: THE INTERSECTION IN 25MBRC020 IS DOWN-DIP OF THE HIGH-GRADE RESULT IN 25MBRC002.

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FIGURE 3: HIGH-GRADE GOLD AT THE TOP OF FRESH ROCK BETWEEN MULGA BILL & EAGLEHAWK

E: admin@greatboulder.com.au GREATBOULDER.COM.AU ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

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FIGURE 4: SECTION 7062200N AT EAGLEHAWK
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FIGURE 5: PROJECTED LONG SECTION THROUGH MULGA BILL AND EAGLEHAWK, LOOKING WEST

E: admin@greatboulder.com.au GREATBOULDER.COM.AU ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

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Next Steps

Once the Eaglehawk AC program is finished the rig will return to Side Well South to follow up several high-grade gold discoveries from the first round of AC drilling in January and February.

External consultants are working on the Ironbark scoping study. Great Boulder is aiming to have this study delivered within the current quarter.

Discussions are ongoing with the Yugunga Nya Traditional Owner group, and the Company plans to conduct the next round of negotiations for the Ironbark mining agreement within the next few weeks.

This announcement has been approved by the Great Boulder Board.

For further information contact:

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Andrew Paterson Media Managing Director Lucas Robinson Great Boulder Resources Limited Corporate Storytime admin@greatboulder.com.au +61 408 228 889 www.greatboulder.com.au lucas@corporatestorytime.com Follow GBR on LinkedIn Follow GBR on Twitter

E: admin@greatboulder.com.au GREATBOULDER.COM.AU ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

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FIGURE 6: PROSPECT LOCATIONS WITHIN THE SIDE WELL GOLD PROJECT

COMPETENT PERSON’S STATEMENT

Exploration information in this Announcement is based upon work undertaken by Mr Andrew Paterson who is a Member of the Australasian Institute of Geoscientists (AIG). Mr Paterson has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a ‘Competent Person’ as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’ (JORC Code). Mr Paterson is an employee of Great Boulder Resources and consents to the inclusion in the report of the matters based on their information in the form and context in which it appears.

The information that relates to Mineral Resources was first reported by the Company in its announcement to the ASX on 16 November 2023. The Company is not aware of any new information or data that materially affects the information included in this announcement and that all material assumptions and technical parameters underpinning the estimates continue to apply and have not material changed. The Company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcement.

E: admin@greatboulder.com.au GREATBOULDER.COM.AU ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

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FIGURE 7: GBR’S MEEKATHARRA PROJECTS

TABLE 1: SIDE WELL MINERAL RESOURCE SUMMARY, NOVEMBER 2023

			Indicated	Indicated	Indicated	Inferred	Inferred	Inferred		Total
Deposit	Type	Cut-off	Tonnes (kt)	Au (g/t)	Ounces	Tonnes (kt)	Au (g/t)	Ounces	Tonnes (kt)	Au (g/t)	Ounces
Mulga Bill	Open Pit U/ground	0.5 1.0	1,667 733	3.1 3.5	169,000 83,000	2,982 1,130	1.9 3.6	183,000 132,000	4,649 1,863	2.4 3.6	352,000 216,000
	Subtotal		2,399	3.3	252,000	4,112	2.4	316,000	6,511	2.7	568,000
Ironbark	Open Pit U/ground	0.5 1.0	753 0	3.7 0.0	88,000 0	186 0	1.9 0.0	11,000 0	938 0	3.3 0.0	100,000 0
	Subtotal		753	3.7	88,000	186	1.9	11,000	938	3.3	100,000
	Total		3,152	3.4	340,000	4,298	2.4	327,000	7,450	2.8	668,000

Subtotals are rounded for reporting purposes. Rounding errors may occur.

E: admin@greatboulder.com.au GREATBOULDER.COM.AU ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

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TABLE 2: SIGNIFICANT INTERSECTIONS - RC DRILLING

Prospect	Hole ID	From	To	Width	Grade	Comments
Mulga Bill	25MBRC017	28	32	4	0.14	4m composite
		93	96	3	0.86
	25MBRC018	88	92	4	0.11	4m composite
		102	103	1	0.60
		112	116	4	0.10	4m composite
		136	140	4	0.16	4m composite
		140	141	1	1.16
		148	152	4	0.20	4m composite
Eaglehawk	25MBRC019	16	20	4	0.20	4m composite
		70	82	12	2.47
	Including	74	77	3	5.39
		88	92	4	0.11	4m composite
		120	124	4	0.10	4m composite
		140	144	4	0.29	4m composite
		172	176	4	0.14	4m composite
		181	182	1	1.51
	25MBRC020	120	124	4	0.27	4m composite
		136	139	3	8.98
	Including	138	139	1	20.70

Significant intersections are reported at a 0.1g/t Au cut-off for 4m composite samples and a 0.5g/t Au cut-off for 1m samples

TABLE 3: SIGNIFICANT INTERSECTIONS – AC DRILLING

Prospect	Hole ID	From	To	Width	Grade	Comments
Mulga Bill	25SWAC094	0	38	38	No significant intersection
	25SWAC095	76	80	4	2.56	4m composite
		83	88	5	0.10	5m composite
	25SWAC096	108	112	4	0.11	4m composite
		130	133	3	4.53	To EOH
	25SWAC097	97	98	1	0.89	EOH 99m (0.2g/t Au)
Eaglehawk	25SWAC098	0	119	119	No significant intersection
	25SWAC099	94	98	4	0.1	4m composite
	25SWAC100	0	132	132	No significant intersection
	25SWAC101	120	124	4	0.17	4m composite
	25SWAC102	0	114	114	No significant intersection
	25SWAC103	0	125	125	No significant intersection
	25SWAC104	0	125	125	No significant intersection
	25SWAC105	24	28	4	0.21	4m composite
		116	132	16	0.21	4m composites
	25SWAC106	24	32	8	0.22	4m composites
		64	72	8	0.16	4m composites
		84	88	4	0.46	4m composite
		88	97	9	1.67

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

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Prospect	Hole ID	From	To	Width	Grade	Comments
	25SWAC107	113	114	1	1.66
		121	122	1	0.50
	25SWAC108	116	124	8	0.25
	25SWAC109	32	36	4	0.12	4m composite
		115	117	2	1.07
	25SWAC110	112	116	4	0.15	4m composite
	25SWAC111	94	99	5	2.10
		104	108	4	1.11	4m composite
	25SWAC112	118	119	1	0.76	EOH
	25SWAC113	0	158	158	No significant intersection
	25SWAC114	24	28	4	0.11	4m composite
		44	48	4	0.13	4m composite
		120	128	8	0.28	4m composites
	25SWAC115	0	130	130	No significant intersection
	25SWAC116	60	62	2	0.68
		68	69	1	0.62
		72	73	1	0.67
		86	100	14	1.42
	Including	86	88	2	3.01
	And	93	94	1	4.30
		100	104	4	0.52	4m composite
		119	120	1	1.86
	25SWAC117	0	133	133	No significant intersection
	25SWAC118	68	72	4	0.25	4m composite
		92	99	7	0.91	4m comp 92-96m
		128	132	4	0.15	4m composite
	25SWAC119	60	64	4	0.43	4m composite
		128	129	1	1.11
	25SWAC120	16	20	4	0.10	4m composite
		68	84	16	0.20	4m composites
		88	96	8	0.56	4m composites
		108	112	4	0.10	4m composite
		112	113	1	0.77
		152	164	12	0.20	4m composites
	25SWAC121	80	81	1	1.11
		105	106	1	0.76
		119	120	1	0.5
	25SWAC122	56	60	4	0.47	4m composite
		142	143	1	2.61
		144	148	4	0.11	4m composite
	25SWAC123	59	60	1	0.58
	25SWAC124	64	68	4	0.14	4m composite
		72	80	8	0.19	4m composites

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

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Prospect	Hole ID	From	To	Width	Grade	Comments
		112	124	12	0.13	4m composites
		147	148	1	0.63

Significant intersections are reported at a 0.1g/t Au cut-off for 4m composite samples and a 0.5g/t Au cut-off for 1m samples

Collar details for the 4 RC holes were reported to the market in an ASX announcement of 7 April 2025.

TABLE 4: COLLAR DETAILS: AC DRILLING (GDA94, ZONE 50)

Hole ID	Prospect	Easting	Northing	RL	Dip	Azi (Mag)	Total Depth
25SWAC094	Mulga Bill	658534	7061450	510	-60	090	38
25SWAC095	Mulga Bill	658474	7061450	510	-60	090	89
25SWAC096	Mulga Bill	658414	7061450	510	-60	090	133
25SWAC097	Mulga Bill	658354	7061450	510	-60	090	99
25SWAC098	Eaglehawk	658528	7061575	510	-60	090	119
25SWAC099	Eaglehawk	658478	7061575	510	-60	090	99
25SWAC100	Eaglehawk	658428	7061575	510	-60	090	132
25SWAC101	Eaglehawk	658377	7061575	510	-60	090	135
25SWAC102	Eaglehawk	658528	7061650	510	-60	090	114
25SWAC103	Eaglehawk	658478	7061650	510	-60	090	125
25SWAC104	Eaglehawk	658528	7061700	511	-60	090	125
25SWAC105	Eaglehawk	658478	7061700	511	-60	090	139
25SWAC106	Eaglehawk	658428	7061700	511	-60	090	134
25SWAC107	Eaglehawk	658554	7061750	511	-60	090	151
25SWAC108	Eaglehawk	658504	7061750	511	-60	090	144
25SWAC109	Eaglehawk	658537	7061800	511	-60	090	154
25SWAC110	Eaglehawk	658490	7061800	511	-60	090	126
25SWAC111	Eaglehawk	658440	7061800	510	-60	090	124
25SWAC112	Eaglehawk	658436	7061850	510	-60	090	119
25SWAC113	Eaglehawk	658536	7061850	510	-60	090	158
25SWAC114	Eaglehawk	658486	7061850	510	-60	090	134
25SWAC115	Eaglehawk	658566	7061900	510	-60	090	130
25SWAC116	Eaglehawk	658516	7061900	509	-60	090	153
25SWAC117	Eaglehawk	658593	7062100	509	-60	090	133
25SWAC118	Eaglehawk	658512	7062025	509	-60	090	167
25SWAC119	Eaglehawk	658498	7062175	509	-60	090	154
25SWAC120	Eaglehawk	658621	7062150	509	-60	090	172
25SWAC121	Eaglehawk	658571	7062150	509	-60	090	180
25SWAC122	Eaglehawk	658521	7062150	509	-60	090	154
25SWAC123	Eaglehawk	658655	7062250	509	-60	090	164
25SWAC124	Eaglehawk	658605	7062250	509	-60	090	162
25SWAC125	Eaglehawk	658555	7062250	509	-60	090	167
25SWAC126	Eaglehawk	658505	7062250	509	-60	090	177

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

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ABOUT GREAT BOULDER RESOURCES

Great Boulder is a mineral exploration company with a portfolio of highly prospective gold and base metals assets in Western Australia ranging from greenfields through to advanced exploration. The Company’s core focus is the Side Well Gold Project at Meekatharra in the Murchison gold field, where exploration has defined a Mineral Resource of 7.45Mt @ 2.8g/t Au for 668,000oz Au (340koz @ 3.4g/t Au Indicated, 327koz @ 2.4g/t Au Inferred). The Company is also progressing earlystage exploration at Wellington Base Metal Project located in an emerging MVT province. With a portfolio of highly prospective assets plus the backing of a strong technical team, the Company is well positioned for future success.

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CAPITAL STRUCTURE

759M ~$4.25M $1.0M $263k SHARES ON ISSUE CASH LISTED INVESTMENT DAILY LIQUIDITY ASX:GBR As at 31/3/25 Cosmo Metals (ASX:CMO) Average 30-day value traded ~$57M Nil 64.5M ~37% MARKET CAP DEBT UNLISTED OPTIONS TOP 20 OWNERSHIP At $0.075/sh As at 31/12/2024

SHARES ON ISSUE ASX:GBR

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Exploring WA Gold & Developing a Technically focused Undertaking smart, Base Metal assets, significant high grade, exploration team with innovative & located in proximity to large scale gold a strong track record systematic exploration operating mines & system at Side Well of discovery infrastructure

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Ongoing drilling at multiple projects providing consistent, material newsflow

E: admin@greatboulder.com.au GREATBOULDER.COM.AU ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

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Appendix 1 - JORC Code, 2012 Edition Table 1 (GBR Drilling, Side Well Project)

Section 1 Sampling Techniques and Data

(Criteria in this section apply to all succeeding sections.)

Criteria	Commentary
Sampling techniques	At the Side Well Project GBR has collected data from auger sampling and from AC, RC and Diamond drilling techniques. This section encompasses all four methods. RC samples were collected into calico bags over 1m intervals using a cyclone splitter. The residual bulk samples are placed in lines of piles on the ground. 2 cone splits are taken off the rig splitter for RC drilling. Visually prospective zones were sampled over 1m intervals and sent for analysis while the rest of the hole was composited over 4m intervals by taking a scoop sample from each 1m bag. Core samples are selected visually based on observations of alteration and mineralisation and sampled to contacts or metre intervals as appropriate. Once samples are marked the core is cut in half longitudinally with one half taken for assay and the other half returned to the core tray. AC samples were placed in piles on the ground with 4m composite samples taken using a scoop. Auger samples are recovered from the auger at blade refusal depth. Auger drilling is an open-hole technique.
Drilling techniques	Industry standard drilling methods and equipment were utilised. Auger drilling was completed using a petrol-powered hand-held auger.
Drill sample recovery	Sample recovery data is noted in geological comments as part of the logging process. Sample condition has been logged for every geological interval as part of the logging process. Water was encountered during drilling resulting in minor wet and moist samples with the majority being dry. No quantitative twinned drilling analysis has been undertaken.
Logging	Geological logging of drilling followed established company procedures. Qualitative logging of samples includes lithology, mineralogy, alteration, veining and weathering. Abundant geological comments supplement logged intervals.
Sub-sampling techniques and sample preparation	1m cyclone splits and 4m speared composite samples were taken in the field. Samples were prepared and analysed at ALS Laboratories Perth for the RC drilling and Intertek Laboratories for the AC drilling. Samples were pulverized so that each samples had a nominal 85% passing 75 microns. Au analysis was undertaken using Au-AA26 involving a 50g lead collection fire assay and Atomic Adsorption Spectrometry (AAS) finish. For AC drilling, Au analysis was undertaken at Intertek using a 50g lead collection fire assay with ICP-OES finish (FA50/OE). Multi-element analysis was completed at both ALS and Intertek Laboratories. Digestion was completed using both 4 Acid and Aqua-regia and analysed by ICP-AES and ICP-MS (Intertek code 4A/MS48, ALS codes ME-MS61, ME-ICP41-ABC).
Quality of assay data and laboratory tests	All samples were assayed by industry standard techniques. Fire assay for gold; four-acid digest and aqua regia for multi-element analysis.
Verification of sampling and assaying	The standard GBR protocol was followed for insertion of standards and blanks with a blank and standard inserted per 25 for RC drilling and 40 samples for AC drilling. Field Duplicates as second cone splits are inserted within known ore zones to assess repeatability. Analysis of ME was typically done on master pulps after standard gold analysis with a company multi-element standard inserted every 50 samples. No QAQC problems were identified in the results. No twinned drilling has been undertaken.
Location of data points	Sample locations and mapping observations were located and recorded electronically using a handheld GPS. Coordinates were recorded in GDA94 grid in Zone 50, which is the GDA94 zone for the Meekatharra area. Drill holes were positioned using the same technique. Hole collars were initially picked up after drilling using a handheld GPS. RC and Diamond hole collars were subsequently surveyed with a DGPS for greater accuracy. This accuracy is sufficient for the intended purpose of the data.

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

GREATBOULDER.COM.AU

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Data spacing and distribution	The spacing and location of the majority of drilling in the projects is, by the nature of early exploration, variable. The spacing and location of data is currently only being considered for exploration purposes.
Orientation of data in relation to geological structure	Drilling is dominantly perpendicular to regional geological trends where interpreted and practical. Wherever possible, cross sections are shown to give a visual indication of the relationship between intersection width and lode thickness. The spacing and location of the data is currently only being considered for exploration purposes.
Sample security	GBR personnel are responsible for delivery of samples from the drill site to the Toll Ipec dispatch center in Meekatharra. Samples are transported by Toll Ipec from Meekatharra to the laboratories in Perth.
Audits or reviews	Data review and interpretation by independent consultants on a regular basis. Group technical meetings are usually held monthly with input from independent expert consultants in the fields of geochemistry, petrology, structural geology and geophysics.

Section 2 Reporting of Exploration Results

(Criteria listed in the preceding section also apply to this section.)

Criteria	Commentary
Mineral tenement and land tenure status	Side Well tenement E51/1905 is a 48-block exploration license covering an area of 131.8km2 immediately east and northeast of Meekatharra in the Murchison province. The tenement is a 75:25 joint venture between Great Boulder and Zebina Minerals Pty Ltd. Aircore drilling was completed on P51/3178 and P51/2978 located directly south of E51/1905. These tenements are held in a 80:20 joint venture between Great Boulder and Wanbanna Pty Ltd.
Exploration done by other parties	Tenement E51/1905 has a protracted exploration history but it is relatively unexplored compared to other regions surrounding Meekatharra.
Geology	The Side Well tenement group covers a portion of the Meekatharra-Wydgee Greenstone Belt north of Meekatharra, WA. The north-northeasterly-trending Archaean Meekatharra-Wydgee Greenstone Belt, comprises a succession of metamorphosed mafic to ultramafic and felsic and sedimentary rocks belonging to the Luke Creek and Mount Farmer Groups. Over the northern extensions of the belt, sediments belonging to the Proterozoic Yerrida Basin unconformably overlie Archaean granite-greenstone terrain. Structurally, the belt takes the form of a syncline known as the Polelle syncline. Younger Archaean granitoids have intrusive contacts with the greenstone succession and have intersected several zones particularly in the Side Well area. Within the Side Well tenement group, a largely concealed portion of the north-north-easterly trending Greenstone Belt is defined, on the basis of drilling and airborne magnetic data, to underlie the area. The greenstone succession is interpreted to be tightly folded into a south plunging syncline and is cut by easterly trending Proterozoic dolerite dykes. There is little to no rock exposure at the Side Well prospect. This area is covered by alluvium and lacustrine clays, commonly up to 60 metres thick. Subcrop exposures of laterite, mafic and ultramafic rocks are present along the eastern side of the project, however exposure of outcrop is still relatively poor.
Drill hole Information	A list of the drill hole coordinates, orientations and intersections reported in this announcement are provided as an appended table in the relevant announcements for each drilling program.
Data aggregation methods	Results were reported using cut-off levels relevant to the sample type. For composited samples significant intercepts were reported for grades greater than 0.1g/t Au with a maximum dilution of 4m. For single metre splits, significant intercepts were reported for grades greater than 0.5g/t Au with a maximum dilution of 3m. A weighted average calculation may be used to allow for bottom of hole composites that were less than the standard 4m and when intervals contain composited samples plus 1m split samples. No metal equivalents are used.

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: admin@greatboulder.com.au GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement

15

29 APRIL 2025

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Relationship between mineralisation widths and intercept lengths	The majority of drilling was conducted using appropriate perpendicular orientations for interpreted mineralisation. Stratigraphy appears to be steeply dipping to the west however mineralisation may have a different orientation. Cross sections are shown wherever possible to illustrate relationships between drilling and interpreted mineralisation.
Diagrams	Refer to figures in announcement.
Balanced reporting	It is not practical to report all historical exploration results from the Side Well project. Selected historical intercepts have previously been re-reported by GBR to highlight the prospectivity of the region, however the vast majority of work on the project has been completed by GBR and reported in ASX announcements since 14 July 2020.
Other substantive exploration data	Subsequent to Doray Minerals Limited exiting the project in 2015, private companies have held the ground with no significant work being undertaken. Wanbanna Pty Ltd has done limited work consisting mainly of AC drilling around the Burke’s Reward and Golden Bracelet prospect’s further south.
Further work	Further work is discussed in the document.

E: admin@greatboulder.com.au ABN 70 611 695 955

ASX Code: GBR Contact: Andrew Paterson, Managing Director P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005

GREATBOULDER.COM.AU