The project is a 50:50 Joint Venture between Antilles Gold Inc (a 100% subsidiary of Antilles Gold Limited) and Gold Caribbean Mining SA, which is a subsidiary of the Cuban state-owned mining company Geominera SA. The Joint Venture is registered as Minera La Victoria SA (“MLV”).
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Summary:
The Nueva Sabana Project comprises a set of porphyritic dioritic intrusions along an extensive trend that includes the El Pilar-Gaspar-Camilo prospects. The overlying gold oxide zone is associated with deeply weathered roots of a gold-rich high sulphidation lithocap that partially overlies the upper zone of a porphyry copper system and associated copper-rich diatreme breccias. Widespread porphyrystyle veining is also found, both within the diorite intrusives and in the host rocks, as quartz-pyrite chalcopyrite veins and chlorite-pyrite veins.
Geological Setting
The Nueva Sabana deposit is hosted within the volcanic island arc rocks of the Caobilla Formation (Coniacian – Lower Campanian, 89-72 Ma, M. Iturralde-Vinent, 1981), which is a bimodal volcanic sequence of predominantly lavas and tuffs of basic composition and minor acidic equivalents. During the Cretaceous, the Caobilla Formation was intruded by diorites and granodiorites which now occupy the central part of the Camagüey province, to the east. These intrusives are genetically linked to the formation of magmatic-hydrothermal systems associated with the porphyry, diatreme breccia and high-sulphidation metallic mineralisation within the belt.
The emplacement of the suite of intrusives and magmatic-hydrothermal breccias was controlled by regional transform faults of a sinistral corridor, the El Pilar Structural Corridor, to the west and the Gaspar Fault to the east, which is interpreted from regional aeromagnetics and ground magnetics.
MLV Geological Interpretation
MLV has determined that the oxide gold zone at the Nueva Sabana Deposit is associated with the deeply eroded remnants of a high-sulphidation gold-rich lithocap, accompanied by a secondary copper enrichment zone. This copper enrichment zone partially overprints the upper section of a copper-rich porphyry system, which is further characterised by copper-rich hydrothermal breccias and diatremes. Porphyry-style veinlets and veins are observed both within the diorite and quartz-diorite intrusives, as well as in the surrounding host rocks. These vein types include A-type sinuous quartz veinlets, ABtype semi-sinuous quartz-chalcopyrite veinlets, EB-type early biotite veinlets, quartz-pyritechalcopyrite veinlets (B-type, quartz with a central line of sulphides), pyrite-chalcopyrite veinlets (Ctype), and D-type sericite-haloed quartz-sulphide veinlets.
The gold oxide zone is associated with the presence of hematite (20% to 50% disseminated and in veinlets). Hematite is associated with advanced argillic alteration from surface. The presence of vuggy silica alteration is interpreted to be part of the lithocap above the advanced argillic alteration. Gold is found preferentially in the argillic alteration, commonly associated with hydrothermal breccias.
Below the gold in oxide is a zone of copper mineralisation with decreasing hematite and increasing secondary chalcocite at the transition between advanced argillic to intermediate argillic. The copper sulphide zone appears below the intermediate argillic alteration down to the base of the argillic alteration zone where primary chalcocite, chalcopyrite and pyrite occur. The sulphides occur in the thickest zones of argillic alteration associated with identified early and inter-mineral porphyries. The periphery of the deposit is chlorite altered with pyrite chlorite veins.
Dimensions
• The Nueva Sabana (formerly El Pilar) deposit is defined over a 600 m strike and is dominantly flat lying. Some lodes are interpreted to have a vertical aspect, steeply dipping. Mineralisation is commonly thick, up to 20 m, with minor distal mineralisation along lithological contacts quite thin, modelled to down to 2 m.
• The resource shows depth potential, and though drilling at depth is limited, the resource is reported to approximately 150 m below the surface (-100 m RL).
• Mineralisation strikes NE (UTM) and dips shallowly to the SE ~10-20°, with a perceived plunge to the SW, ~5°.
• The steep central proportion of the deposit with elevated copper is expected to propagate to depth and is still open.