Maiden Mineral Resource estimate and Exploration Target
At El Palmar, Sunstone has achieved the following milestones:
Maiden T1 Mineral Resource
Maiden T1 Mineral Resource estimate (MRE) of 1.2Moz AuEq
- The initial pit-constrained MRE is based solely on the outcropping T1 gold-copper porphyry deposit at El Palmar of 64Mt at 0.60g/t AuEq for 1.2Moz AuEq at a cut-off grade of 0.4g/t AuEq.
- T1, which is at surface, is only one of several gold-copper porphyry deposits at El Palmar.
- T1 has potential to be advanced as a large open pit opportunity before undertaking exploration and development of the deeper porphyry opportunities.
- The T1 MRE is based on only 17,699 metres of drilling, highlighting the scope to rapidly grow the El Palmar resource base.
Gold and copper Exploration Target of 15M - 45Moz AuEq
The initial Exploration Target is between 1.0Bt to 1.2Bt at a grade between 0.3g/t to 0.7g/t gold and 0.1% to 0.3% copper for contained metal of between 10Moz and 27Moz gold and 1.0 to 3.7Mt copper. This is in addition to the maiden MRE.
- The Exploration Target has been estimated from only three deposits, meaning there is still immense potential to grow at El Palmar.
- 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.
Overview of 9 of the 10 exploration targets defined on the El Palmar concession. View is looking at -20 degrees towards azimuth 215o.
Maiden Mineral Resource estimate
The initial MRE, from the T1 target only, is 64Mt at 0.60g/t AuEq1 (0.41g/t gold, 0.13% copper and 0.7g/t silver) for 1.2Mozs AuEq at a cut-off grade of 0.4g/t AuEq1 (reported in accordance with the JORC Code[1], see Table 1 below for more detail). Preliminary pit optimisation was applied to the deposit to constrain the MRE and demonstrate the potential to be mined economically by open pit methods. A very low strip ratio is implied by the block model geometry within the pit.
El Palmar Mineral Resource estimate at a 0.40g/t AuEq cutoff grade - Geologically unconstrained by oxidation state and total (AuEq takes into account Ag and Cu) in Optimisation Shell.
Notes
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Figures may not sum due to rounding
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Significant figures do not imply an added level of precision
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Reported at 0.40g/t AuEq cutoff grade - criteria from Sunstone
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Model: EP_global_blank_okmodel_pass4_pdomALL_20x20x30_30x80x20_subblock_comb_subSG
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AuEq (g/t and ounces) accounts for Au (g/t), Cu (%) and Ag (g/t) value and AuEq (g/t and ounces) must not be totalled to Cu (% and/or lbs and/or tonnes) or Ag (g/t and/or ounces)
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Unconstrained pdoms estimates
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In accordance with Sunstone metallurgical investigations the Au recovery is at 0.90, Ag recovery is at 0.60 and the Cu recovery is at 0.78
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In accordance with Sunstone metal price investigations and projections the Au price is set at USD$1800/oz, Ag price is set at USD$22/oz and Cu price is set at USD$4.5/lb
The MRE is based on 21 drill holes for 17,699m of drilling (18 drilled by Sunstone in the period August 2021 to July 2022, and 3 drilled by Codelco in 2012) and 1,498 linear metres of trenching in 5 trenches.
Sunstone engaged independent consulting firm, Spiers Geological Consultants (SGC), to prepare the initial MRE for the T1 deposit at El Palmar.
El Palmar Mineral Resource estimate at various cut-off grades
Notes: consistent with Table 1 above
- Inside pit results
- Category: Indicated + Inferred (Total)
El Palmar T1 resource block model and pit outline. Nearby Exploration Target areas T1 Western Deep, T2, and T3 also shown.
El Palmar T1 resource block model and pit outline along a 240-060o cross-section and showing the exploration targets which are located within, on the sides, and immediately below the modelled T1 open pit.
Initial El Palmar Exploration Target
The initial El Palmar Exploration Target is between approximately 1.0Bt and 1.2Bt at a grade between 0.3g/t to 0.7g/t gold and 0.1% to 0.3% copper for contained metal of between 10M ozs to 27Mozs gold and 1.0Mt to 3.7Mt copper. The Exploration Target range is in addition to the maiden MRE.
The Exploration Target has been reported in accordance with the JORC Code. The potential quantity and grade of the Exploration Target is conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource for the target area reported. It is uncertain if further exploration will result in the estimation of a Mineral Resource.
The table below summarises the Exploration Target components. These comprise ‘in-pit’ material that does not have adequate drill density to be included in the MRE, extensions of the MRE domains laterally and to depth outside the pit, and new domains with limited drill support at this stage.
El Palmar Exploration Target
Note: figures may not sum due to rounding
The Exploration Target comprises material from the T1, T2, T3 and T5 targets at El Palmar and extends across an area of 1.6km x 1.1km. It includes near-surface mineralisation and deeper mineralisation to depths of 1,500m below surface (see more detailed explanatory notes below). The areas of mineralisation captured in the Exploration Target are of high conviction, geologically robust domains consistent with high aspect ratio, clustered porphyry gold-copper deposits. There is potential for the copper content to increase in areas interpreted to be central to the porphyry systems.
El Palmar Exploration Target domains below and marginal to the resource pit.
Cross section showing the T2-related Exploration Targets from surface extending to depth to the large T3 target. Note that the MRE and pit are located ‘behind’ this image to the west
