Great Southern Copper completes float sampling at Victoria prospect
Published by Isabelle Keltie,
Global Mining Review,
Great Southern, a company focused on copper-gold exploration in Chile, has announced final assay results from its trial rock float sampling programme at its Victoria prospect, one of several prospects currently under evaluation at the Especularita Project.
- Vein-breccia style mineralisation with assay results up to 2.1% Cu and 4.29g/t Au.
- 39% of rock float samples assay over 1% Cu, and 67% of samples assay over 0.5% Cu.
- Multiple outcropping vein-breccia structures identified with evidence of high-grade copper.
- Prospect exploration on-going with results from mapping and outcrop sampling expected.
- No previous drilling in the prospect area.
The Victoria prospect is one of several areas currently under investigation within GSC’s Especularita Project. Victoria comprises a gently sloping field covered by soil and copper-mineralised float (surface boulders) located adjacent to the southern margin of the Colorada advanced argillic lithocap. The mineralised float is characteristic of high-grade, structurally-controlled vein breccias.
A programme of float sampling was trialed on an approximate 200 x 200 m grid across the boulder field with samples collected on approximately 25 m intervals. The programme was designed to characterise the mineralisation style and grade and identify potential outcropping source rocks.
Sam Garrett, Chief Executive Officer of Great Southern Copper, said: “We are very pleased with the results of our float sampling programme at Victoria which demonstrate the potential for high-grade Cu-Au deposits in the area. The prospect is rapidly developing into a potentially high-grade Cu-Au target for the company and we are eagerly awaiting the results of our Phase 2 work which has identified multiple outcropping structures with evidence of the style of copper mineralisation that is observed in the float samples. The results continue to highlight that the Especularita Project is an extensively mineralised district exhibiting evidence of a broad range of mineralisation styles characteristic of both porphyry and intrusion-related Cu-Au systems.”
Victoria prospect results
The Victoria prospect was discovered as a “boulder field” comprising abundant blocky float of quartz-specularite ± sulphide breccia and hornfelsed volcanics. Float of carbonate (siderite) and quartz-carbonate breccia is also common. The mineralized breccia float is observed over an approximate 200 x 500 m area within a larger west-sloping scree slope that obscures the underlying geology. To the north the scree slope is apparently fault-bound against the Colorada advanced argillic lithocap and to the west and south the shallow gravel overlaps the dominant granodiorite intrusive. To the east the slope rises into hornfelsed volcanics. Both the granite and volcanics exhibit evidence of overprinting quartz-carbonate+sulphide-filled structures.
Mineralised float boulders typically comprise clasts (or fragments) of andesitic volcanics hosted in a matrix of massive to crustiform silica with variable amounts of coarse disseminated chalcopyrite-pyrite-specularite. Early observations suggest that the silica alteration-brecciation event is multi-phased. Late carbonate is commonly seen to infill the open-space quartz veins.
Systematic selective sampling of the breccia float material was completed on a 25 x 25 m grid to gauge the tenor and variability of the copper grades. Out of a total of 49 grid samples (including 23 samples released in a previous update), 48 samples were anomalous in copper (>0.1% Cu) with 39% of samples returning grades over 1.0% Cu, and 67% samples assayed over 0.5% Cu. 37% of samples were anomalous in gold (>0.1g/t Au) with 8% of samples over 1g/t Au. The highest assay grades were 2.1% Cu and 4.29 g/t Au. The breccia samples were also weakly anomalous in Zn and Pb.
Mapping and sampling is ongoing at Victoria with the aim of better understanding the geology of the area and defining the styles, grades and extent of mineralisation. We look forward to sharing these results as they arise.
Especularita Project Exploration Programme
Also within the Especularita Project, exploration is ongoing at the Teresita prospect, where Au-Cu mineralisation associated with anastomosing quartz-carbonate vein swarms has now been mapped over a 2 km strike length and is open both along and across strike. GSC’s recently expanded concession area has increased the mineralisation target footprint at Teresita with evidence of further veins as well as breccia-hosted Cu-Au mineralisation.
The regional stream sediment sampling programme is also continuing at Especularita with over 400 stream samples collected from a total of over 500 planned sample locations. The programme is designed to test the entire Especularita project area (approx. 18 200 ha) for anomalous Cu-Au targets for follow-up exploration.
Prospect scale work has also now commenced at the Aurelia prospect where recent reconnaissance exploration identified high-grade Cu-Au mineralisation associated with skarn alteration of volcanic and carbonate rocks in contact with the granodiorite batholith. The alteration system is mapped over an extensive area and is similar to that of the El Espino Cu-Au skarn deposit located approximately 10 km to the southeast.
Read the article online at: https://www.globalminingreview.com/exploration-development/28032023/great-southern-copper-completes-float-sampling-at-victoria-prospect/
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