Great Southern Copper plc (LON: GSCU) has commenced diamond drilling at its Artemisa prospect in Chile, following a significant copper-molybdenum discovery that has strengthened the company’s exploration model for a potentially larger porphyry copper system beneath the La Colorada lithocap.
The drilling forms part of Great Southern Copper’s ongoing exploration at its Especularita Project, where a previous reconnaissance programme identified copper mineralisation from surface and geological indicators pointing towards additional targets beneath the extensive La Colorada alteration system.
The initial diamond drilling programme comprises two holes totalling approximately 500 metres, designed to investigate the mineralisation discovered in reverse circulation (RC) drillhole ART26-RC009.
That hole returned 106 metres grading 0.33% copper and 42 parts per million molybdenum from surface, including a higher-grade interval of 54 metres at 0.46% copper and 66ppm molybdenum from 16 metres.
The results provide a priority target for follow-up exploration, with diamond drilling expected to deliver more detailed information about the host rocks, alteration patterns and structural controls associated with the mineralisation.
Diamond drillhole ART26-DH018 is currently underway, positioned behind the earlier RC intersection and drilled at a steeper angle to better understand the geological relationships.
A second hole will investigate the mineralised vein structures from a different orientation, helping the company refine its interpretation before undertaking further drilling.
Subject to the results, Great Southern Copper intends to follow the diamond programme with approximately 2,000 metres of additional RC drilling to evaluate the near-surface extent of copper-molybdenum mineralisation at Artemisa.
The company also reported encouraging geological findings from its wider scout drilling programme around the western and southwestern margins of the La Colorada lithocap.
The reconnaissance campaign comprised 17 RC holes totalling 2,474 metres, completed across four target areas: Piedras Blancas, Artemisa North, Victoria and Artemisa South.
At Piedras Blancas, approximately 1.2 kilometres north of the Artemisa discovery, drilling identified alteration associated with porphyry copper systems, including the transition from phyllic alteration near surface to potassic alteration at depth.
Great Southern Copper believes these observations provide an exploration vector towards the east and south, potentially indicating the location of additional copper mineralisation.
At Artemisa North, multiple drillholes intersected porphyry-style alteration and copper-bearing structures, with mineralisation remaining open towards the east and northeast in the direction of the La Colorada lithocap.
Meanwhile, drilling at Victoria and Artemisa South identified mineralised vein and breccia structures, with the geological interpretation suggesting increasing prospectivity towards the northern portions of the system.
Although several of these intersections returned relatively modest copper grades, their alteration characteristics provide information for identifying potential mineralised centres.
The La Colorada lithocap covers more than 75 square kilometres, making it a substantial exploration target within the Especularita property.
The company believes that parts of the original alteration system have been eroded, potentially exposing the upper levels of porphyry copper systems around its margins.
This interpretation is supported by the discovery at Artemisa and the presence of related alteration patterns at neighbouring prospects, although the existence, size and grade of any concealed deposits remain to be established through drilling.
Great Southern Copper is now compiling geological mapping, soil geochemistry and mineral spectroscopy data to identify priority drill targets beneath La Colorada.
The work is designed to locate alteration zones that could provide indicators of concealed porphyry copper mineralisation.
Initial scout drilling beneath the lithocap is planned within the next three to six months, subject to completion of the technical targeting work and operational preparations.
The Especularita Project is situated at relatively low elevation within Chile’s coastal metallogenic belt, with access to established infrastructure and mining services.
It lies along a regional geological trend associated with significant copper deposits and projects, including Los Pelambres, Altar and El Pachón.
Great Southern Copper holds rights to acquire 100% of Especularita, including the Artemisa discovery and the wider La Colorada exploration targets.
Chief Executive Sam Garrett described the Artemisa discovery as an important development for the company’s exploration strategy, particularly because the copper-molybdenum mineralisation begins at surface.
He said the results supported the company’s interpretation that the La Colorada lithocap could be associated with a wider porphyry copper system.
Garrett also highlighted the project’s favourable location and the potential for additional discoveries through systematic exploration.
The immediate priority is to complete the two-hole diamond drilling programme at Artemisa, establish the geological controls on the copper-molybdenum mineralisation and use those findings to guide the planned follow-up RC campaign.
For investors, the 106-metre copper intersection provides an established exploration result, while the broader lithocap represents a potentially larger but substantially less tested opportunity.
The next significant milestones will be the diamond drilling results, confirmation of the follow-up RC programme and identification of the first targets beneath La Colorada, as Great Southern Copper advances its search for potentially significant porphyry copper deposits in Chile.
