Great Southern Copper Plc (LON: GSCU) has completed its first scout reverse circulation drilling programme at the Especularita Project in Chile, where the company is targeting large-scale porphyry copper systems.
The copper-gold-silver explorer completed 17 scout RC holes for a total of 2,474 metres drilled across four target areas on the western and southern margins of the La Colorada lithocap.
The company said the La Colorada advanced argillic lithocap is vast in scale and is interpreted to represent the upper high-sulphidation levels of an alteration system that may overlie porphyry-related copper mineralisation.
Drilling was designed to improve geological interpretation in areas around the lithocap, where Great Southern Copper believes erosion may have exposed underlying porphyry-style alteration at surface.
The company said porphyry copper-style alteration was identified in drilling at Piedras Blancas, Artemisa North and Victoria.
At Piedras Blancas and Artemisa North, drill holes intersected diorites and locally porphyritic microdiorites with strong to intense magnetite-biotite-pyrite alteration. These were overprinted by chlorite-sericite alteration, disseminated pyrite and local quartz-pyrite stockwork veinlets.
Great Southern Copper said this alteration is consistent with the outer phyllic alteration zone of a porphyry copper system.
Of particular interest, the company reported potassic alteration at shallow depths in the bottoms of holes RC001 at Piedras Blancas and RC008 at Artemisa North. The company said this may suggest the system improves towards the lithocap and that a potential porphyry centre could be close to surface.
At Victoria and Artemisa South, drilling also encountered variable magnetite-biotite alteration, although the company said phyllic-style alteration was less intense and appeared more structurally controlled.
Chief executive Sam Garrett said the programme had successfully tested the flanking margins of the large lithocap system at Especularita.
“This programme is important because it will allow us to vector future drilling within the lithocap to target areas that have the most potential to host copper and gold mineralisation,” he said.
Garrett added that the drilling had proven effective in testing four prospect targets and had already suggested the presence of porphyry-related phyllic alteration at surface, as well as potassic alteration at shallow depths.
First assay results from the scout drilling programme are expected within the next two to four weeks.
Great Southern Copper said the results will be used alongside spectral, geochemical and geophysical data to plan the next phase of exploration drilling at La Colorada, targeting both high-sulphidation gold-silver-copper and porphyry copper mineralisation.
Exploration is also continuing elsewhere across Especularita. Mapping and sampling are ongoing at the Cerro Negro and Viuda prospects, while planning is underway for extensions to the Cerro Negro induced polarisation survey, expected to begin during July or August 2026.
The company said results from the planned geophysical work, together with ongoing mapping and sampling, will guide future drilling at Cerro Negro, Viuda and other prospects across the project.
Great Southern Copper holds rights to own 100% of the Especularita Project, which is located at low elevation with strong access to infrastructure and mining services. The project lies along trend from major copper deposits including Los Pelambres, Altar and El Pachon.
