Introduction Sunstone Metals Limited (“Sunstone” or “Company”) is an ASX-listed mineral exploration company with two high-quality gold and copper projects in Ecuador: 1. The Bramaderos Project, located in Southern Ecuador, has both at-surface and deeper porphyry goldcopper systems and contains an initial Mineral Resource estimate of 156Mt at 0.53g/t AuEq for 2.7Moz AuEq1,2. JORC Classification Tonnage (Mt) Au (g/t) Cu (%) Ag (g/t) AuEq2 (g/t) AuEq2 (Mozs) Indicated 9 0.38 0.09 1.1 0.53 0.2 Inferred 147 0.35 0.11 1.3 0.53 2.5 Total 156 0.35 0.11 1.3 0.53 2.7 Additionally, the Bramaderos Project has a porphyry Exploration Target3 of between 3.3Moz and 8.6Moz AuEq within 255Mt to 360Mt at a grade between 0.40 and 0.74g/t AuEq1,2, and the Limon epithermal gold-silver Exploration Target of 0.9 - 1.7Moz AuEq4 within 30Mt - 44Mt at a grade between 0.9 - 1.2g/t AuEq4,5. The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Resource for the exploration target area reported. It is uncertain if further exploration will result in the estimation of a Resource. 2. The El Palmar Project is located in northern Ecuador, 60km north-west of Ecuador’s capital Quito. The property sits on the regionally significant Toachi Fault Zone that hosts a number of world-class copper porphyry systems. The Project has both at-surface and deeper porphyry gold-copper systems and an initial Mineral Resource estimate of 64Mt at 0.60g/t AuEq6,7 for 1.2Moz AuEq6. Average Grade Material Content JORC Classification Tonnage (Mt) AuEq6 (g/t) Au (g/t) Ag (g/t) Cu (ppm) Cu (%) AuEq6 (Koz) Au (Koz) Ag (Koz) Cu (Kt) Indicated 5 0.63 0.42 0.81 1,456 0.15 100 100 100 7 Inferred 59 0.59 0.40 0.65 1,290 0.13 1,100 700 1,200 70 Total 64 0.60 0.41 0.66 1,301 0.13 1,200 800 1,300 80 Additionally, the El Palmar Project has a porphyry Exploration Target3 of between 15Moz and 45Moz AuEq within 1.0Bt to 1.2Bt at a grade between 0.3 - 0.7g/t gold and 0.1 – 0.3% copper5. Overview Operating Review 1 Refer ASX Announcement on 13 December 2022. 2 The gold equivalent calculation formula for porphyry gold-copper-silver mineralisation at Bramaderos is AuEq(g/t) = (Au grade x Au price x Au recov / 31.1035) + (Ag grade x Ag price x Ag recov / 31.1035) + (Cu grade x Cu price x Cu recov / 100)) / (Au price x Au recov / 31.1035). The prices used were US$1,800/oz gold and US$9,500/t copper and US$22/oz silver. Recoveries are estimated at 89% for gold, 85% for copper, and 60% for silver based on metallurgical studies. Grades for the Exploration Target are 0.24g/t Au and 0.10% Cu. In Sunstone’s opinion all the elements included in the metal equivalents calculation have reasonable potential to be recovered and sold. 3 The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Resource for the exploration target area reported. It is uncertain if further exploration will result in the estimation of a Resource. 4 Refer ASX Announcement on 5 February 2024. 5 The gold equivalent calculation formula for the Limon epithermal gold-silver mineralisation is AuEq(g/t) = Au(ppm) + (Ag (ppm)/82). The prices used were US$1,800/oz gold and US$22/oz silver. Recoveries are estimated at over 90% for gold and 90% for silver from metallurgical studies. In Sunstone’s opinion all the elements included in the metal equivalents calculation have reasonable potential to be recovered and sold. 6 Refer ASX Announcement on 22 October 2024. 7 The gold equivalent calculation formula for porphyry gold-copper-silver mineralisation at El Palmar is AuEq (g/t) = ((Au grade x Au price x Au recov / 31.1035) + (Ag grade x Ag price x Ag recov / 31.1035) + (Cu grade x Cu price x Cu recov / 100)) / (Au price x Au recov / 31.1035). The prices applied were US$1,800/oz gold, US$4.50/lb copper and US$22/oz silver. Recoveries are estimated at 90% for gold, 78% for copper (excluded for oxide material), and 60% for silver based on metallurgical studies. Grades for the Exploration Target are 0.30g/t Au and 0.10% Cu. In Sunstone’s opinion all the elements included in the metal equivalents calculation have reasonable potential to be recovered and sold. 4 Sunstone Metals Limited Annual Report 2025
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