Don Julio Cluster
- Sable holds the rights to acquire 100% ownership of 58,629 hectares.
- 19 initial aster-mineral occurrence anomalies
- First 2 years work done over 9 of the 19 anomalies.
- The group of 9 anomalies is comprised in an area of 12×12 km called the Don Julio Cluster.
- Sable’s work has defined multiple large porphyry – epithermal systems within the Don Julio Cluster
- Potential for large Au-Ag–base metal deposits
- 6 targets ready to drill at the end of 2020
- Drill permits ready
- 59 km to Barrick’s Alturas deposit (8.9Moz inferred resource) as of December 2018
- 130 km to Barrick’s Veladero mine (2.5 MOz reserves; 1.8MOz resources) as of December 2018; plus past production
- Possible Extension of El Indio-Pascua District (50Moz+)
- Extensive Au, Ag, Cu, base metal surface anomaly
- Located in Argentina’s Mining Friendly San Juan Province
- Option to Earn 100%
The Don Julio Au (Cu) project is situated on the eastern margin of the Cordillera Principal of Argentina and may represent the southern extension of the well-endowed El Indio-Pascua mineral belt which hosts 50Moz+ Au.
The Don Julio Gold Project is located in the municipalities of Calingasta and Iglesia in the Province of San Juan, Argentina. Road access to the Don Julio project from the city of San Juan driving north for 165 km along the paved road that connects San Juan with the town of Iglesia and then west for 11 km south of Iglesia following the gravel road 431 for 35 km to arrive the project site.
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Geology of the Don Julio Cluster of Targets
The local geology is represented by a sequence of Carboniferous metasedimentary rocks (Agua Negra Formation) that has formed the basement of two different magmatic arcs. The oldest arc (≈280Ma) is widely recognized in Argentina and Chile and includes both intrusive and volcanic rocks. The youngest arc represents Miocene subduction (8 to 5 Ma) and it is especially notorious by the presence of a semi-preserved large composite stratovolcano (Tocota stratovolcano) that deposited andesitic to dacitic ignimbrite and lava flows with thicknesses >1km discordantly over Permian and Carboniferous rocks. Miocene intrusives of 8 and 5 Ma are extensively present over the property. The proximal zone of the Tocota stratovolcano exhibits significant zones of advanced argillic alteration controlled by structures and also by the Miocene-Paleozoic unconformity. The Esperanza and Heaven Hill areas are high-sulfidation mineralization targets where extensive Au-Ag-Cu anomalies are associated to the mentioned advanced argillic alteration. These two targets were the focus of initial Sable’s exploration and scout drilling in late 2018.
The spatial association and overprinting of these two magmatic arcs make Don Julio a rich and unique district where six additional targets with different styles of mineralization have been identified after intensive geological mapping and rock sampling. A summary of each of these targets is provided below.
The Fermin skarn is the most recently found mineralized area at Don Julio. Geological mapping has shown that the mineralization is hosted by a limestone unit interbedded within Permian ignimbrites. The calcareous unit is strongly deformed and altered to marble, and hornfels, with irregular zones of garnet skarn. Mineralization consists of sphalerite, galena, chalcopyrite, and pyrite, normally with stratabound geometry, but also controlled by structures crosscutting the bedding or showing irregular geometries. The altered and mineralized calcareous unit outcrops for 1.9 km along strike and show variable thickness up to 100m.
Au is only weakly anomalous, whereas Zn, Pb, Ag and Cu show multiple elevated values (Sable’s Press Releases June 20th, 2019 and February 12, 2020). The mineralogy and characteristics of the alteration suggest that Fermin represents the distal zone of a concealed Cu-Au skarn/porphyry center located west of the outcropping mineralized area and that will be the focus of future exploration.
Lodo is an Intermediate Sulfidation (IS) target associated with a regional, 5 km long, NW structure that can be divided into two areas: Lodo North and Lodo South. Lodo North comprises a series of parallel structures with combined thickness up to 80m that exhibit a typical IS epithermal vertical zoning being rich in Mn/Ca/Fe carbonate, barite and fluorite at the upper part (≈4300 masl) changing to a silica>carbonate zone around 4100 masl. The geochemical expression is coincident with the vertical zoning showing values up to 0.33 ppm Au, 48.8 ppm Ag, 2.3% ppm Mn, 1% Zn, 1.38% Pb, 1280 ppm As, and 5390 ppm Ba. The upper part of Lodo North is characterized by an extensive silicified zone interpreted as a silica cap below the palaeo-water table. Both the structures and the silica zone are hosted by Carboniferous sandstones.
Lodo south is a remarkably continuous vein also with NW strike that runs for >2km with a thickness between 2 and 10m. The vein is composed mainly by opaline silica with carbonate and it is hosted by a Permian granite. Lodo South vein is interpreted to be at a higher level within the epithermal system compared to Lodo North and therefore its geochemical expression is weaker.
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San Gabriel is a multi-kilometer Intermediate sulfidation (IS) target where multiple veins hosted by granite exhibit textures and mineralogy typical of a high level epithermal system. San Gabriel includes multiple sub-targets that will see scout drilling, including Veta Boca, Bombonera, Veta River, among others. The geochemical expression of the San Gabriel upper level epithermal veins is one of the most significant within the Don Julio district. Rock samples show values as high as 7.6 g/t Au, 188 g/t Ag; 1.3% Pb; 2400 ppm Zn; 2450 ppm Cu; 617 ppm As; 4820 ppm Ba; 5550 ppm Mn; 18 ppm Hg; 2490 ppm Bi; 1.15% Mo; and 1980 ppm W.
Our mapping had identified that many of the upper level epithermal veins crosscut an earlier mineralization style of possible Intrusion Related (IR) affinity, likely associated with the emplacement of the Permian intrusive rocks. IR mineralization features includes crystalline quartz, abundant sulfides, and multiple rhyolite dykes and surrounding granite and sandstones mineralized with galena, sphalerite, pyrite, and arsenopyrite.
This unique association of precious and base metal anomaly combined with epithermal and an earlier IR pathfinders demonstrates the high potential of San Gabriel.
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Colorado target was found after follow up of a silica aster anomaly. A structurally controlled hydrothermal breccia hosted by Carboniferous metasediments shows strongly anomalous Au and Ag values, as high as 5.64 g/t Au and 164 g/t Ag. The breccia shows low-temperature silica in the matrix with fragments of sandstones and porphyritic rocks, some of them with porphyry type veinlets. The structure that hosts the breccia shows a transition from high to IS including the presence of dickite and enargite at its southern portion that gradually disappears to the north. Other IS structures and high sulfidation (HS) silica ledges occur in the area and might represent additional potential. Strong and extensive silicification in sandstones is observed on the hanging wall of the Colorado structure.
La Gringa area is located at the northern extreme of the HS advanced argillic alteration of Amarillo ridge, which was the focus of historical exploration before Sable optioned the Don Julio property. A dacitic and a dioritic porphyry stocks outcrop on both sides of the wide Chita valley exhibiting a combination of advanced argillic and porphyry style features including: A and B type veinlets; banded Maricunga type veinlets; alunite, pyrophyllite, and tourmaline alteration; and possible remnants of sericite. This combination is typical of the transition between a lithocap and the top of a porphyry deposit. Au anomaly reaches 0.3 g/t Au in early porphyry veinlets and > 3g/t Au in selected HS structures that crosscut the dacitic intrusion. A concealed Au-Cu porphyry target is interpreted below quaternary gravels at the center of the valley.
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Tocota is the area with the largest volume of Miocene magma within the entire Don Julio project. A large dacitic to andesitic stock that is interpreted by Sable as the preserved core of a large stratovolcano is spatially surrounded by advanced argillic that forms the HS centers of Amarillo, Esperanza, and Heaven Hill. On the southern flank of the Tocota stock Sable has identified several zones with abundant floats of diorites with early porphyry veinlets with values up to 0.3 g/t Au and 0.3% Cu in grab samples. A large part of the area is covered by talus and will require geophysics and scout drilling to identify a potentially mineralized porphyry center.
Exploration to Date
Sable initiated exploration at the property in late 2018, focused on the HS targets of Esperanza and Heaven Hill, after which the company started an intensive mapping and prospection program around different parts of the property finding the six targets described above. The mapping campaign included >35 km2 of detailed mapping at 1:2500 scale; the company has also collected 1680 rock and 253 talus samples over the different described targets. In late 2019 the geology team started recognition and basic exploration of some of the targets located outside the main Don Julio cluster, including Oti, Las 40 and Amarillas, collecting 190 rock samples and 23 stream sediment samples.
The company is now focused on some additional structural mapping to better understand the geometries of the mineralization at San Gabriel and Fermin and also planning to start a large UAV magnetic survey covering the entire property to design the best drilling plan for the 2020-2021 season.
Sable initially drilled 3101m of core drilling in 11 drillholes at Esperanza and Heaven Hill targets obtaining weak Au anomalies associated with advanced argillic alteration on the Miocene – Carboniferous unconformity but not intercepting significant mineralization. The six targets located within the Don Julio cluster and described above are all drill permitted and the company is designing the most appropriate drilling plan to test them.