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GREAT BOULDER RESOURCES LIMITED Capital/Financing Update 2025

Dec 7, 2025

64967_rns_2025-12-07_1264a524-6223-4861-9fb5-eb96f4895d27.pdf

Capital/Financing Update

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ASX Announcement
8 DECEMBER 2025
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SIDE WELL EXPLORATION UPDATE

HIGHLIGHTS

Assays have been received from recent RC drilling programs at Eaglehawk, Mulga Bill East and Golden Bracelet within the Side Well Gold Project

  • Further high-grade intersections at Eaglehawk include:

  • 1m @ 481.00g/t Au from 129m in 25EHRC041

  • 3m @ 7.97g/t Au from 62m, including 1m @ 21.30g/t Au from 62m in 25EHRC042

  • These results are from the same RC program that intersected 105m @ 2.41g/t Au from 95m in 25EHRC040 announced 10 November 2025

  • Highlights from other RC drilling programs include:

  • 5m @ 5.82g/t Au from 134m in 25MBRC039 at Mulga Bill East

  • 24m @ 1.37g/t Au from 76m, including 8m @ 3.57g/t Au from 76m in 25MBRC048 at Mulga Bill East

  • 12m @ 1.14g/t Au from 24m, including 8m @ 1.64g/t Au from 28m in 25SWRC063 at Golden Bracelet

Great Boulder Resources (“ Great Boulder ” or the “ Company ”) (ASX: GBR ) is pleased to provide an update on recent drilling at the Company’s flagship Side Well Gold Project[1] (“ Side Well ”) near Meekatharra in Western Australia which hosts a MRE of 668,000oz @ 2.8 g/t Au.

Great Boulder’s Managing Director, Andrew Paterson commented:

“Eaglehawk continues to deliver new high-grade intersections outside the area of the pending resource. The 481.00g/t result appears to sit within a new west-dipping quartz lode, and further drilling is expected to confirm our interpretation.”

“The final round of resource definition drilling at Golden Bracelet added confidence to the two interpreted main zones, with broad intersections of gold mineralisation defined. Resource estimation for that deposit is now underway.”

“At present we have three rigs busy at Side Well testing targets for our next phase of growth: the RC rig is currently at Flagpole completing resource definition holes, while the Diamond rig is drilling deep holes at Mulga Bill testing longer-term growth opportunities. Meanwhile regional AC drilling continues over multiple target areas.”

1 Please refer to the Tenements table in GBR’s recent quarterly report for relevant joint venture interests

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement 8 DECEMBER 2025

2

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“Resource estimation is progressing well for the five deposits which will comprise our imminent MRE update. We anticipate a busy end to 2025, which will set the Company in good stead for a solid start in January.”

Side Well Gold Project

Great Boulder’s flagship Side Well Gold Project is located in the heart of the Meekatharra gold field neighbouring Westgold Resources’ (ASX:WGX) Paddy’s Flat operation. The project currently hosts a Mineral Resource Estimate (MRE) of 7.45Mt @ 2.9g/t Au for 668,000oz, as announced in late 2023 (Table 1). The Company is pleased to be on track to deliver an updated MRE by the end of 2025. Side Well is surrounded by mining infrastructure in the rapidly growing Murchison region.

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FIGURE 1: THE SIDE WELL PROJECT IS STRATEGICALLY LOCATED IN THE NORTHERN MURCHISON

Eaglehawk Deposit

Six RC holes were drilled at Eaglehawk for 1,140m, with assay results from three holes announced on 10 November 2025 including the intersection of 105m @ 2.41g/t Au from 95m in 25EHRC040, in a newly discovered cross-cutting structure striking approximately northwest to southeast and dipping towards the northeast. Further RC drilling has since been completed to confirm the strike and dip of this zone, with assays pending.

Significant intersections from the other holes in this program include:

E: [email protected] 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

ASX Announcement 8 DECEMBER 2025

3

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  • 1m @ 481.00g/t Au from 129m in 25EHRC041

  • 3m @ 7.97g/t Au from 62m, including 1m @ 21.30g/t Au from 62m in 25EHRC042.

Hole 25EHRC039 was abandoned at 90m prior to reaching the target depth due to ground conditions.

A further 13 RC holes for 2,601m have since been completed at Eaglehawk testing the newly identified cross-structure as well as other extensional targets at depth and along strike. Assays for these holes are expected to be received during December.

A cross-section showing the interpreted high-grade vein intersected by 25EHRC040 will be published after additional drilling is completed.

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FIGURE 2: NEW RC RESULTS AT EAGLEHAWK

E: [email protected] 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

ASX Announcement

4

8 DECEMBER 2025

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Mulga Bill East

23 RC holes for 3,747m were drilled at Mulga Bill East, targeting a north-northeast-trending zone of gold mineralisation first identified in GBR’s early drilling programs in 2021-22. The majority of significant intercepts appear to be related to high grade west dipping vein sets that are hosted in a newly identified “eastern” dacitic stratigraphic unit. The identification of this unit, that has similarities to the host at the central Mulga Bill deposit, highlights the growth potential both along strike and down-dip.

This trend is less defined by drilling, however its proximity to the main Mulga Bill deposit suggests potential for Mulga Bill East mineralisation to be exploited by a future open pit mining operation. Highlights from this program include:

  • 4m @ 3.36g/t Au from 76m, 3m @ 9.49g/t Au from 134m and 5m @ 2.69g/t Au from 163m in 25MBRC039 north of the current resource

  • 24m @ 1.37g/t Au from 76m, including 8m @ 3.57g/t Au from 76m in 25MBRC048

  • 9m @ 2.09g/t Au from 105m, including 2m @ 5.00g/t Au from 105m in 25MBRC040 north of the current resource

  • 8m @ 1.98g/t Au from 148m in 25MBRC042 east of the current resource

  • 5m @ 1.88g/t Au from 99m in 25MBRC033 north of the current resource.

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FIGURE 3: MULGA BILL EAST SECTION SHOWING RECENT RESULTS IN WEST-DIPPING VEINS

E: [email protected] 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

ASX Announcement

5

8 DECEMBER 2025

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FIGURE 4: PLAN VIEW OF RECENT RC RESULTS FROM MULGA BILL EAST

Side Well South / Golden Bracelet

Assays have been received for the final 22 RC holes for 3,447m drilled at Side Well South during recent resource definition work.

The Side Well South name was originally used as a general geographic reference, however the deposit will now be known as Golden Bracelet, taking its name from a nearby historic mine working.

Highlights from the recent drilling include:

  • 12m @ 1.14g/t Au from 24m, including 8m @ 1.64g/t Au from 28m in 25SWRC063

E: [email protected] 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

ASX Announcement 8 DECEMBER 2025

6

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  • 7m @ 1.45g/t Au from 121m in 25SWRC059

  • 5m @ 1.55g/t Au from 94m in 25SWRC049

  • 16m @ 0.95g/t Au from 72m in 25SWRC054.

These results confirm and add confidence to the Company’s interpretation of the two main mineralised trends at Golden Bracelet. Lithology, regolith and mineralisation wireframes have been updated with the new data and estimation is underway for the initial Golden Bracelet mineral resource estimate (MRE).

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FIGURE 5: RECENT DRILLING RESULTS FROM GOLDEN BRACELET

E: [email protected] 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

ASX Announcement

7

8 DECEMBER 2025

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FIGURE 6: GOLDEN BRACELET SECTION 704935N SHOWING SOME OF THE RECENT INTERSECTIONS

Ironbark Progress

Negotiations for a Mining Agreement with the Yugunga Nya Traditional Owner group are continuing. Once the Ironbark MRE is updated the Company will prepare an updated economic assessment of likely mining scenarios which will form the basis of the proposed royalty structure under the agreement. Compensation clauses including royalties are the final section of the agreement to be decided. The Mining Agreement is a prerequisite for grant of the Ironbark mining lease, which is itself a prerequisite for a mining approval application.

Field programs relating to the Ironbark mining approval application have been completed. Final consultants’ reports are expected to be received shortly.

Next Steps

External consultants are working on resource estimates for Mulga Bill, Ironbark, Eaglehawk, Saltbush and Golden Bracelet, with an updated project-wide MRE anticipated later this month.

Diamond drilling is continuing on the EIS co-funded program of deeper holes testing high-grade targets beneath Mulga Bill and Ironbark. This program is intended to demonstrate the large-scale potential of this multi-kilometre intrusive-related gold system, with drilling expected to continue into

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement 8 DECEMBER 2025

8

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early 2026. Great Boulder has secured up to $180,000 in co-funded drilling from the WA Government’s Exploration Incentive Scheme (EIS) for this drilling.

RC drilling will continue working on priority targets at Flagpole and Eaglehawk to continue extending and infilling zones of high-grade gold. Recent results and any subsequent drilling success at Eaglehawk will demonstrate immediate upside to the pending maiden Eaglehawk MRE, which is based upon drilling completed up to the end of October.

AC drilling continues testing a range of targets, with recent drilling around the Flagpole prospect south of Mulga Bill, follow-up holes based on results of recent testing between Mulga Bill and Ironbark and drilling within the Ironbark corridor to complete testing of stratigraphic and IP-generated targets.

This announcement has been approved by the Great Boulder Board.

For further information contact:

Andrew Paterson Managing Director Great Boulder Resources Limited [email protected] www.greatboulder.com.au

Media Lucas Robinson Corporate Storytime +61 408 228 889 [email protected]

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Follow GBR on LinkedIn

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Follow GBR on X

COMPETENT PERSON’S STATEMENT

The information in this Announcement that relates to Exploration Targets and Exploration Results 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 previously reported by the Company in its announcement to the ASX on 16 November 2023 ‘Side Well Mineral Resource Increases to 688Koz Au’, a copy of which is available on the Company’s website at https://www.greatboulder.com.au/investors/asx-announcements/. 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: [email protected] 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

ASX Announcement

9

8 DECEMBER 2025

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FIGURE 7: SIDE WELL GOLD PROJECT DEPOSITS AND OTHER PROSPECTS

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.

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

GREATBOULDER.COM.AU

ASX Announcement

10

8 DECEMBER 2025

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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 its 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

1,041M ~$16.3M $1.33M $263k SHARES ON ISSUE CASH LISTED INVESTMENT DAILY LIQUIDITY ASX:GBR As at 30 Sep 25 Cosmo Metals (ASX:CMO) Average 30-day value traded $80M Nil 102M ~39% MARKET CAP DEBT UNLISTED OPTIONS TOP 20 OWNERSHIP At $0.08/sh As at 30 Sep 25

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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: [email protected] 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

ASX Announcement

11

8 DECEMBER 2025

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TABLE 2: SIGNIFICANT INTERSECTIONS – EAGLEHAWK RC

Prospect Hole ID From To Width Grade Comments
Eaglehawk 25EHRC037 88 92 4 0.24 4m composite
(Previously announced) 102 103 1 1.21
25EHRC038 116 120 4 0.93 4m composite
(Previously announced) 144 148 4 0.14 4m composite
174 175 1 0.58
25EHRC039 0 90 90 Hole abandoned at 90m
25EHRC040 24 28 4 0.25 4m composite
(Previously announced) 95 200 105 2.41 4m comps from 188m
Including 102 105 3 18.85
And 114 127 13 5.17
And 180 186 6 5.08
204 212 8 0.29
25EHRC041 129 130 1 481.00
25EHRC042 51 52 1 0.54
62 65 3 7.97
Including 62 63 1 21.30
68 72 4 0.63 4m composite
124 128 4 0.10 4m composite
156 164 8 2.01 4m composites
172 180 8 0.63 4m composites

TABLE 3: SIGNIFICANT INTERSECTIONS – GOLDEN BRACELET RC

Prospect Hole ID From To Width Grade Comments
Golden Bracelet 25SWRC045 17 18 1 0.79
20 21 1 0.58
27 54 27 0.62 4m comps 28 - 44m
27 28 1 1.71
28 44 16 0.42 4m composites
44 54 10 0.83
65 77 12 0.79
154 155 1 0.61
164 165 1 1.29
25SWRC046 12 16 4 0.13 4m composite
19 20 1 0.81
37 40 3 1.16
100 108 8 0.13 4m composites
124 128 4 0.28 4m composite
25SWRC047 92 93 1 0.62
158 162 4 1.20
168 172 4 0.93
177 178 1 0.52

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement

12

8 DECEMBER 2025

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Prospect Hole ID From To Width Grade Comments
25SWRC048 16 18 2 1.23
22 24 2 0.89
28 29 1 1.16
36 39 3 1.57
43 44 1 1.76
25SWRC049 72 80 8 0.19
85 87 2 0.95
89 90 1 0.57
94 99 5 1.55
25SWRC050 59 60 1 0.66
81 82 1 0.90
101 102 1 1.39
117 120 3 0.81
25SWRC051 27 29 2 0.73
31 32 1 0.53
33 34 1 0.50
109 115 6 0.52
118 119 1 0.92
126 127 1 0.89
131 134 3 0.65
25SWRC052 67 68 1 0.51
75 76 1 0.54
86 87 1 0.56
109 115 6 0.80
197 199 2 0.86
203 207 4 1.20
25SWRC053 16 24 8 0.14 4m composites
169 170 1 0.76
174 175 1 0.80
177 178 1 1.45
198 199 1 0.56
25SWRC054 61 62 1 1.39
72 88 16 0.95
25SWRC055 206 207 1 0.52
25SWRC056 91 92 1 0.97
135 139 4 0.64
144 145 1 0.96
164 165 1 0.90
167 169 2 1.07
173 178 5 1.40
25SWRC057 98 101 3 0.65
104 105 1 0.61
108 112 4 0.46 4m composite

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

GREATBOULDER.COM.AU

ASX Announcement

13

8 DECEMBER 2025

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Prospect Hole ID From To Width Grade Comments
116 124 8 0.25 4m composites
25SWRC058 146 148 2 0.69
25SWRC059 121 128 7 1.45
130 131 1 1.27
133 134 1 1.76
154 159 5 1.01
25SWRC060 34 35 1 0.51
44 48 4 1.07
52 54 2 1.15
25SWRC061 16 18 2 1.22
20 22 2 1.06
24 26 2 1.67
28 32 4 0.58
34 36 2 0.95
25SWRC062 100 104 4 0.15 4m composite
107 110 3 1.37
116 119 3 1.03
25SWRC063 24 36 12 1.14 4m composites
Including 28 36 8 1.64 4m composites
58 60 2 0.60
77 78 1 0.92
81 89 8 1.36
100 104 4 1.06 4m composite
25SWRC064 20 24 4 0.16 4m composite
31 33 2 0.97
38 39 1 0.67
48 52 4 0.26 4m composite
56 60 4 0.17 4m composite
63 65 2 1.12
76 88 12 0.21 4m composites
89 94 5 0.77
25SWRC065 97 102 5 0.72
111 114 3 0.61
125 126 1 0.59
129 130 1 0.96
154 155 1 1.29
25SWRC066 120 128 8 0.23 4m composites

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.

E: [email protected] 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

ASX Announcement

14

8 DECEMBER 2025

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TABLE 4: SIGNIFICANT INTERSECTIONS – MULGA BILL EAST RC

Prospect Hole ID From To Width Grade
Comments
Mulga Bill East
25MBRC027
48 56 8 0.20 4m composites
68 76 8 0.27 4m composites
96 100 4 0.11 4m composite
25MBRC028 113 115 2 1.00
126 127 1 0.66
25MBRC029 0 134 134 No significant intersection
25MBRC030 124 125 1 0.97
25MBRC031 104 116 12 0.21 4m composites
120 123 3 0.18 3m comp to EOH
25MBRC032 0 146 146 No significant intersection
25MBRC033 28 32 4 0.11 4m composite
99 104 5 1.88
25MBRC034 24 28 4 0.17 4m composite
80 84 4 0.39 4m composite
112 128 16 0.20 4m composites
25MBRC035 112 120 8 0.31 4m composites
161 162 1 0.81
25MBRC036 88 92 4 0.65 4m composite
118 119 1 0.51
143 144 1 3.11
25MBRC037 40 44 4 0.14 4m composite
108 120 12 0.45 4m composites
25MBRC038 68 72 4 0.27 4m composite
84 88 4 0.16 4m composite
136 137 1 0.54
140 141 1 0.87
143 146 3 0.96
25MBRC039 76 80 4 3.36 4m composite
96 100 4 0.32 4m composite
134 139 5 5.82
144 148 4 0.24 4m composite
160 168 8 1.92
176 180 4 0.12 4m composite
184 187 3 1.23
25MBRC040 80 84 4 0.13 4m composite
102 103 1 0.96
105 114 9 2.09
Including
105
107 2 5.00
25MBRC041 76 84 8 0.23 4m composites
108 116 8 0.35 4m composites
172 176 4 0.12 4m composite
25MBRC042 32 36 4 0.27 4m composite

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] 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

8 DECEMBER 2025

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Prospect Hole ID From To Width Grade
Comments
80 84 4 0.10 4m composite
88 92 4 0.34 4m composite
96 100 4 0.89 4m composite
148 156 8 1.98
160 164 4 0.14 4m composite
25MBRC043 80 84 4 0.22 4m composite
104 112 8 0.24 4m composites
139 140 1 0.77
25MBRC044 78 80 2 0.60
81 82 1 1.45
109 110 1 0.60
160 161 1 0.69
25MBRC045 76 84 8 0.75 4m composites
157 158 1 3.02
25MBRC046 72 76 4 1.24 4m composite
113 114 1 0.50
164 166 2 1.18
236 240 4 0.25 EOH 4m composite
25MBRC047 84 96 12 0.18 4m composites
116 117 1 0.51
25MBRC048 76 100 24 1.374m composites
Including
76
84 8 3.574m composites
135 136 1 1.75
25MBRC049 64 68 4 0.57 4m composite
76 80 4 1.29 4m composite
161 162 1 2.22
184 185 1 0.58

TABLE 5: COLLAR DETAILS – RECENT RC DRILLING (GDA94, ZONE 50)

Hole ID Prospect Easting Northing RL Dip Azi Total
(Mag) Depth
25SWRC045 Golden Bracelet 660455 7049424 516 -60 90 172
25SWRC046 Golden Bracelet 660433 7049449 517 -60 90 166
25SWRC047 Golden Bracelet 660391 7049450 516 -60 90 190
25SWRC048 Golden Bracelet 660497 7049499 517 -60 90 64
25SWRC049 Golden Bracelet 660460 7049499 517 -60 90 130
25SWRC050 Golden Bracelet 660580 7049549 518 -60 90 130
25SWRC051 Golden Bracelet 660463 7049550 518 -60 90 202
25SWRC052 Golden Bracelet 660683 7049301 516 -50 270 214
25SWRC053 Golden Bracelet 660536 7049450 516 -60 90 226
25SWRC054 Golden Bracelet 660635 7049249 515 -50 270 112
25SWRC055 Golden Bracelet 660332 7049300 515 -56 90 226

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement

16

8 DECEMBER 2025

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Hole ID Prospect Easting Northing RL Dip Azi Total
(Mag) Depth
25SWRC056 Golden Bracelet 660387 7049400 516 -60 90 190
25SWRC057 Golden Bracelet 660649 7049201 516 -50 270 160
25SWRC058 Golden Bracelet 660366 7049251 514 -60 90 178
25SWRC059 Golden Bracelet 660377 7049349 515 -60 90 178
25SWRC060 Golden Bracelet 660580 7049365 515 -46 110 88
25SWRC061 Golden Bracelet 660485 7049400 516 -60 90 58
25SWRC062 Golden Bracelet 660536 7049350 515 -60 90 202
25SWRC063 Golden Bracelet 660417 7049350 515 -60 90 124
25SWRC064 Golden Bracelet 660607 7049415 516 -55 120 106
25SWRC065 Golden Bracelet 660567 7049400 516 -60 90 166
25SWRC066 Golden Bracelet 660567 7049500 517 -60 90 165
25MBRC027 Mulga Bill East 658703 7061150 511 -60 87 104
25MBRC028 Mulga Bill East 658642 7061151 510 -60 87 146
25MBRC029 Mulga Bill East 658583 7061150 510 -60 87 134
25MBRC030 Mulga Bill East 658523 7061150 510 -60 87 128
25MBRC031 Mulga Bill East 658610 7060975 510 -60 87 123
25MBRC032 Mulga Bill East 658556 7060975 511 -60 87 146
25MBRC033 Mulga Bill East 658635 7060850 511 -60 87 134
25MBRC034 Mulga Bill East 658574 7060850 511 -60 87 146
25MBRC035 Mulga Bill East 658513 7060849 510 -60 87 176
25MBRC036 Mulga Bill East 658657 7060774 511 -60 87 158
25MBRC037 Mulga Bill East 658548 7060774 511 -60 87 176
25MBRC038 Mulga Bill East 658645 7060675 511 -60 87 170
25MBRC039 Mulga Bill East 658598 7060675 511 -60 87 194
25MBRC040 Mulga Bill East 658583 7060749 511 -60 90 144
25MBRC041 Mulga Bill East 658533 7060748 511 -60 90 180
25MBRC042 Mulga Bill East 658643 7060625 511 -60 90 168
25MBRC043 Mulga Bill East 658511 7060525 511 -60 90 204
25MBRC044 Mulga Bill East 658591 7060524 511 -60 90 168
25MBRC045 Mulga Bill East 658574 7060276 512 -60 90 198
25MBRC046 Mulga Bill East 658486 7060274 512 -60 90 240
25MBRC047 Mulga Bill East 658614 7060251 512 -60 90 150
25MBRC048 Mulga Bill East 658600 7060225 512 -60 90 162
25MBRC049 Mulga Bill East 658577 7060175 512 -60 90 198
25EHRC043 Eaglehawk 658390 7061652 510 -60 87 222
25EHRC044 Eaglehawk 658321 7061701 510 -60 87 216
25EHRC045 Eaglehawk 658448 7061764 509 -60 200 186
25EHRC046 Eaglehawk 658462 7061803 509 -60 200 210
25EHRC047 Eaglehawk 658381 7061835 509 -63 193 220
25EHRC048 Eaglehawk 658404 7061809 509 -63 195 210
25EHRC049 Eaglehawk 658362 7061785 509 -60 196 155

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement

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8 DECEMBER 2025

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Hole ID Prospect Easting Northing RL Dip Azi Total
(Mag) Depth
25EHRC050 Eaglehawk 658505 7061975 509 -60 90 114

TABLE 6: COLLAR DETAILS – RECENT AC DRILLING (GDA94, ZONE 50)

Hole ID Prospect Easting Northing
RL
Dip Azi Total Depth
(Mag)
25SWAC455 Flagpole 658159
7056700

514
-60 90 136
25SWAC456 Flagpole 658132
7056700

514
-60 90 143
25SWAC457 Flagpole 658160
7056760

514
-60 90 128
25SWAC458 Flagpole 658107
7056760

514
-60 90 129
25SWAC459 Flagpole 658212
7056896

514
-60 90 122
25SWAC460 Flagpole 658177
7056900

514
-60 90 135
25SWAC461 Flagpole 658033
7056903

514
-60 90 146
25SWAC462 Flagpole 658169
7056925

514
-60 90 165
25SWAC463 Flagpole 658123
7056925

514
-60 90 168
25SWAC464 Flagpole 658161
7056950

514
-60 90 183
25SWAC465 Flagpole 658156
7056975

514
-60 90 135
25SWAC466 Flagpole 658183
7057000

514
-60 90 159
25SWAC467 Flagpole 658164
7057000

514
-60 90 168
25SWAC468 Flagpole 658091
7057000

514
-60 90 143
25SWAC469 Flagpole 658222
7056700

514
-60 90 111
25SWAC470 Flagpole 658273
7056760

514
-60 90 132
25SWAC471 Flagpole 658217
7056760

514
-60 90 111
25SWAC472 Flagpole 658222
7056826

514
-60 90 120
25SWAC473 Flagpole 658122
7056895

514
-60 90 114
25SWAC474 Flagpole 658362
7056896

514
-60 90 104
25SWAC475 Flagpole 658312
7056896

514
-60 90 105
25SWAC476 Flagpole 658262
7056896

514
-60 90 114
25SWAC477 Flagpole 658382
7057000

514
-60 90 108
25SWAC478 Flagpole 658332
7057000

514
-60 90 116
25SWAC479 Flagpole 658282
7057000

514
-60 90 117
25SWAC480 Flagpole 658232
7057000

514
-60 90 120
25SWAC481 Flagpole 658162
7057042

514
-60 90 150
25SWAC482 Flagpole 658251
7057140

514
-60 90 144
25SWAC483 Flagpole 658195
7057140

514
-60 90 144
25SWAC484 Flagpole 658140
7057140

514
-60 90 129
25SWAC485 Flagpole 658085
7057140

514
-60 90 102
25SWAC486 Flagpole 658540
7057200

514
-60 90 102
25SWAC487 Flagpole 658478
7057200

514
-60 90 96
25SWAC488 Flagpole 658416
7057200

514
-60 90 108
25SWAC489 Flagpole 658374
7057265

514
-60 90 117

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] GREATBOULDER.COM.AU P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

ASX Announcement

18

8 DECEMBER 2025

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Hole ID Prospect Easting Northing
RL
Dip Azi Total Depth
(Mag)
25SWAC490 Flagpole 658314
7057265

514
-60 90 48
25SWAC491 Flagpole 658255
7057265

514
-60 90 132
25SWAC492 Flagpole 658205
7057265

514
-60 90 120
25SWAC493 Flagpole 658155
7057265

514
-60 90 147
25SWAC494 Flagpole 658494
7057330

514
-60 90 90
25SWAC495 Flagpole 658434
7057330

514
-60 90 117
25SWAC496 Flagpole 659044
7056800

514
-60 90 93
25SWAC497 Flagpole 658989
7056800

514
-60 90 45
25SWAC498 Flagpole 658934
7056800

514
-60 90 42
25SWAC499 Flagpole 658879
7056800

514
-60 90 80
25SWAC500 Flagpole 657884
7057000

514
-60 90 120
25SWAC501 Flagpole 657834
7057000

514
-60 90 114
25SWAC502 Flagpole 657784
7057000

514
-60 90 96
25SWAC503 Flagpole 657734
7057000

514
-60 90 105
25SWAC504 Flagpole 657684
7057000

514
-60 90 105
25SWAC505 Flagpole 657924
7057200

514
-60 90 120
25SWAC506 Flagpole 657874
7057200

514
-60 90 136
25SWAC507 Flagpole 657824
7057200

514
-60 90 122
25SWAC508 Flagpole 657774
7057200

514
-60 90 114
25SWAC509 Flagpole 657724
7057200

514
-60 90 144
25SWAC510 Flagpole 657864
7056800

514
-60 90 126
25SWAC511 Flagpole 657814
7056800

514
-60 90 120
25SWAC512 Flagpole 657764
7056800

514
-60 90 102
25SWAC513 Flagpole 657714
7056800

514
-60 90 95
25SWAC514 Flagpole 657664
7056800

514
-60 90 108

E: [email protected] 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

ASX Announcement

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8 DECEMBER 2025

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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 are 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 are sampled over 1m intervals and sent for analysis while the rest
of the hole is 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.
All core is oriented in order to measure and record structural orientations.
AC samples are placed in piles on the ground with 4m composite samples taken using a scoop.
Any composite samples assaying 0.1g/t Au or more are re-assayed in 1m intervals.
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. Where water
is encountered during drilling the resultant sample quality is noted as being dry, moist or wet.
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 are taken in the field. Samples are prepared
and analysed at ALS Laboratories Perth for RC and diamond drilling and Intertek Laboratories for
the AC drilling and auger soil samples.
Samples are pulverized so that each sample has a nominal grainsize of 85% passing 75 microns. Au
analysis is undertaken using Au-AA26 involving a 50g lead collection fire assay and Atomic
Adsorption Spectrometry (AAS) finish. For AC drilling, Au analysis is undertaken at Intertek using a
50g lead collection fire assay with ICP-OES finish (FA50/OE).
Multi-element analysis is completed at both ALS and Intertek Laboratories. Digestion is 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 are 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 is 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 is 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 are located and recorded electronically using a handheld
GPS. Coordinates are recorded in GDA94 grid in Zone 50, which is the GDA94 zone for the
Meekatharra area.

ASX Code: GBR Contact: Andrew Paterson, Managing Director E: [email protected] P: +61 8 9321 6037 Level 1, 51 Colin St West Perth WA 6005 ABN 70 611 695 955

GREATBOULDER.COM.AU

ASX Announcement

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Drill holes are positioned using the same technique. Hole collars are initially picked up after drilling
using a handheld GPS. RC and Diamond hole collars are subsequently surveyed with a DGPS for
greater accuracy.
This accuracy is sufficient for the intended purpose of the data.
Data spacing and
distribution
The spacing and location of the majority of drilling in the projects is, by the nature of early
exploration, variable. As each prospect advances the drill spacing is decreased until the confidence
of continuity is sufficient to allow the estimation of a mineral resource. Resource classification (e.g.
Inferred or Indicated) is assigned by an independent resource consultant.
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
centre 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 75%
owned by Great Boulder, with Zebina Minerals Pty Ltd holding a 25% free-carried interest up to a
decision to mine.
E51/1679 and the adjoining prospecting licences south of E5/1905 are mainly held in agreements
with Mark Selga and Wanbanna Pty Ltd which give GBR an 80% interest in those tenements.
P51/3361, P51/3362, P51/3358, P51,3419 and P51/3425 are 100%-owned by GBR.
A full list of the Company’s tenement interests is included in each quarterly activities report available
on the ASX.
Exploration done by
other parties
The Side Well project 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.

E: [email protected] 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

ASX Announcement

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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 are reported using cut-off levels relevant to the sample type. For composited samples
significant intercepts are reported for grades greater than 0.1g/t Au with a maximum internal dilution
of 4m. For single metre splits, significant intercepts are reported for grades greater than 0.5g/t Au
with a maximum internal dilution of 3m.
A weighted average calculation may be used to allow for bottom of hole composites that are less
than the standard 4m and when intervals contain composited samples plus 1m split samples. In such
instances the presence of composite samples within the intersection is noted in the comments.
No metal equivalents are used.
Relationship between
mineralisation widths
and intercept lengths
The majority of drilling is 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: [email protected] 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