Overview

Summary

Ownership

Lunahuasi is 100% owned by NGEx Minerals.

Location

Lunahuasi is located in the Andes Mountains of San Juan Province, Argentina, approximately 10 kilometres south of the Los Helados project located in Region III, Chile.

Access to both Lunahuasi and Los Helados is via Copiapó, Chile (a driving distance of about 177 kilometres), or from San Juan, Argentina (a driving distance of approximately 264 kilometres).

Geology

Lunahuasi is a high-sulfidation (HS) Copper (Cu) – Gold (Au) – Silver (Ag) epithermal deposit associated with a Cu-Au-Molybdeum (Mo) porphyry system, discovered in January 2023 by NGEx. The deposit is located in the central part of the Vicuña District, a NNE-trending structural-magmatic metallogenic corridor extending for approximately 40 km across the northwestern corner of San Juan Province, between the Los Helados porphyry deposit (~10 km to the north) and the Filo del Sol porphyry-epithermal system (~9 km to the south).

The local geology comprises a Permian-Triassic basement of the Choiyoi Group, consisting of rhyolites, rhyolitic ignimbrites, andesitic dikes, and granites (219–249 Ma; U-Pb zircon ages). This basement is unconformably overlain by an Upper Cretaceous volcano-sedimentary succession assigned to the Mogotes Formation, composed of sandstones, conglomerates, and sedimentary breccias with andesitic to dacitic volcanic components. The uppermost stratigraphic unit consists of Lower Miocene tuffs, lapilli tuffs, and felsic ignimbrites of the Escabroso Formation, Doña Ana Group (21.09 ± 0.4 Ma; U-Pb zircon age). An Eocene porphyritic diorite to quartz diorite intrusive body (36 ± 0.6 Ma; U-Pb) intrudes the basement and locally the Mogotes Formation, whereas Middle Miocene porphyritic dioritic dikes (13.3–13.4 Ma; Re-Os molybdenite ages; Creaser, 2025) are interpreted as early and late apophyses of a Cu-Au-Mo porphyry system located west of the explored area.

Two NE-striking dextral fault systems are recognized: the Lunahuasi Fault System and the Lunahuasi South Fault System. These structures developed under a regional strike-slip regime characterized by WSW-ENE compression and NNW-SSE extension. Their overlap defines a transtensional zone in which the local stress field evolved into a mixed strike-slip/normal regime, constituting the principal control on permeability and mineralization. The highest-grade part of the deposit is a fault-related vein network comprising lithified faults, fault-fill veins, and extension vein sets, with ore-shoot geometry and distribution controlled by the interaction between these vein types.

Four superimposed mineralization styles have been identified: (1) disseminated and stockwork HS Cu-Au-Ag mineralization, which forms a broad envelope around the system and grades westward into the porphyry environment; (2) massive HS enargite-pyrite veins carrying exceptionally high Cu, Au, and Ag grades (e.g., DPDH054: 21.7 m at 31.92% CuEq); (3) intermediate-sulfidation quartz veins hosting bonanza-grade gold, characterized by gray amorphous quartz and colloform banding (DPDH046: 1.55 m at 504 g/t Au), interpreted as a late, lower-temperature event; and (4) a Cu-Au-Mo porphyry system marked by A- and B-type quartz veinlets containing chalcopyrite-bornite ± molybdenite and biotite-magnetite potassic alteration (DPDH027: 743 m at 0.56% CuEq).

Hydrothermal alteration displays well-developed zonation. The central part of the system is characterized by a residual quartz core with vuggy silica texture and advanced argillic alteration assemblages of quartz-alunite-dickite-kaolinite ± pyrophyllite ± zunyite ± topaz. This grades laterally into intermediate argillic alteration (kaolinite-pyrite ± dickite) and then into argillic alteration (illite-smectite ± chlorite). At depth and toward the west, potassic alteration (biotite-magnetite, K-feldspar) related to the dioritic porphyry is overprinted by phyllic alteration (quartz-sericite-pyrite) and advanced argillic alteration associated with the lithocap. At surface, the system is capped by powdery quartz and alunite-quartz assemblages linked to a steam-heated environment. Distally, propylitic alteration (chlorite ± epidote ± pyrite ± calcite) characterizes the cores of andesitic dikes and the diorite-quartz diorite intrusive rocks.

Rhyolites of the Choiyoi Group constitute the most favorable host rocks for high-grade mineralization because of their brittle behavior, greater fracture intensity, and susceptibility to acidic fluid alteration. In contrast, andesites behave as relatively impermeable barriers. At greater depths, thinner veins (10–30 cm) are commonly emplaced along rhyolite-andesite contacts, exploiting planes of structural weakness. A preferred elevation for emplacement of the largest and highest-grade veins is recognized between 4,550 and 4,300 m a.s.l. in the Mars and Jupiter zones, extending down to 4,250 m a.s.l. in the Saturn zone.

To date, four drilling campaigns have been completed, totaling approximately 70,000 m in more than 77 drill holes, all of which returned significant intercepts. Mineralization currently defines a minimum volume of 1,100 m (N-S) × 1,200 m (E-W) × 1,200 m (vertical extent) and remains open in all directions.

Exploration

The Lunahuasi deposit was discovered by the second drill hole in the Project’s history, which was collared on February 13, 1013.  The hole intersected a 60 m interval assaying 5.65% Cu, 2.04 g/t Au, and 44.0 g/t Ag.

Drilling since then has totalled 70,570 m in 82 diamond drill holes and has outlined a series of structurally controlled high-sulphidation quartz/pyrite/enargite veins associated with a copper-gold porphyry system.  This mineralization is hosted by structures which are interpreted to be subvertical and to strike north-south to north-northeast. These structures are characterized by massive to semi-massive and disseminated sulphides, principally pyrite and enargite with locally abundant covellite. The sulphides tend to be coarse grained and include some very coarse crystalline sections.

Drilling during the 2024-2025 season was successful in intersecting part of the porphyry mineralization and also intersected ultra high-grade gold values (up to 504 g/t) hosted as free gold in a creamy-silica quartz vein with only minor amounts of sulphides, which represents previously unknown style of mineralization within the deposit.

The vein system at Lunahuasi has minimum dimensions of 1,100 m north-south by 1,200 m east-west by 1,200 m vertical and remains open in all directions.  Only a small part of the porphyry deposit has been intersected, and its ultimate size and grade distribution remain unknown.  The size of the ultra high-grade gold mineralization also remains unknown.  Exploration potential on the Project remains excellent as, in addition to exploring the known mineralized zones, excellent potential remains for discovery of new mineralized zones related to the large porphyry system.