First holes completed for Great Southern Copper drilling programme

Highlights:

• Five scout diamond drill holes completed at two prospect locations, Chinchillon and Central, for a total of 1667.5 m.
• Sheeted fracture-hosted mineralised system confirmed with veinlet and locally disseminated sulfides, including pyrite, chalcopyrite, and molybdenite observed in all holes. 
• First 167 samples for SLD005 submitted to ALS laboratories in La Serena.
• Drilling now testing monzonite-hosted sheeted fracture-vein swarm mineralisation with associated zones of unidirectional solidification textures (UST’s) at Las Hermanas prospect.

Diamond drill holes SLDD005 to SLDD009 targeted highly oxidised sheeted fracture-veins mapped and sampled in outcrop and trenches at the Chinchillon and Central prospects. The holes were planned to test the concept that iron oxide minerals seen on the exposed surfaces of sheeted fractures in outcrops and in trenches is potentially indicative of iron-copper sulfide mineralisation at depth. Geological mapping at San Lorenzo suggests that the sheeted fracture-veins defines a large (>15 km²) alteration system characterised by actinolite-quartz-Kfeldspar±FeCu sulfide±magnetite fracture filling within biotite granodiorite.

At the Chinchillon prospect scout diamond holes SLD005 (451.8 m) and SLD006 (305.8 m) targeted broad zones of oxidised sheeted fracture-vein alteration and anomalous copper and gold assay results observed in outcrops and exploration trenches (CWT 1-2)Both holes intersected pyrite, chalcopyrite, and molybdenite mineralisation associated with targeted fracture-style veining with SLDD005 extended 151.8 m beyond its planned target depth of 300 m.

Drill holes SLD007 (307.9 m), SLD008 (300 m), and SLD009 (302 m) tested similar fracture-hosted Cu-Au mineralisation hosted in biotite granodiorite at the Central prospect. Holes SLD008 and SLD009 also drilled beneath artisanal mine workings. All holes intersected altered granodiorite cut by variably intense sulfide-filled fracture-veins. Sulfide mineralisation observed in the sheeted veinlets includes pyrite, chalcopyrite, and molybdenite. In addition, where vein halo alteration is more intense, further pyrite-chalcopyrite+molybdenite mineralisation may occur as disseminations in the altered wall rock.

The drill rig has now moved to the Las Hermanas prospect and has commenced scout diamond drilling at SLD010 targeting fracture-hosted copper-gold mineralisation associated with a monzonitic dyke intruding the biotite granodiorite host rock.

Drill core is being processed for geological, geotechnical, petrophysical, and geochemical data by GSC staff. Samples of half-drill core for SLD005 (0-324 m, collected over 2 m intervals) have been despatched to ALS laboratories in La Serena, Chile, for sample preparation (drying, weighing, crushing, and grinding). A final 200 g aliquot of each sample is forwarded by ALS to their laboratories in Lima, Peru, where it is assayed for Au (by 30 g fire assay with ICP-AES finish method) plus a suite of 48 base metals and trace elements including Cu and Mo (by four acid digest ICP-MS method). Sampling and assaying QAQC protocols employed by the company for this drilling project include routine insertion of standards and blanks.

Sam Garrett, Chief Executive Officer of Great Southern Copper, said:

“The scout drilling program at San Lorenzo has confirmed the occurrence of sulfide copper hosted in sheeted vein systems which validates our strategy to focus our efforts here. This is a significant milestone for GSC and the project and I congratulate the team on their work thus far. The drilling is confirming that the alteration system which hosts the copper at San Lorenzo is very large and the assay results from these holes will allow us to focus our future exploration efforts toward zones of higher fracture frequency and higher copper grades as well as defining targets for possible IP surveys. The assay results from this programme will also deliver important information about the gold grades and how this relates to copper which we are unable to assess visually. The next phase of this scout drilling programme has started and is currently testing areas of monzonite-hosted mineralisation. We look forward to updating investors on progress in the coming months.”

Read the article online at: https://www.globalminingreview.com/mining/13092022/first-holes-completed-for-great-southern-copper-plc-drilling-programme/