{"id":140816,"title":"Great Southern Copper Reports Strong Mostaza Copper-Silver Recoveries","publisher":"Share Talk","author":"sharetalk","published":"2026-09-21T06:45:18+00:00","modified":"2026-09-21T06:45:18+00:00","canonical_url":"https://www.share-talk.com/great-southern-copper-reports-strong-mostaza-copper-silver-recoveries/","markdown_url":"https://www.share-talk.com/great-southern-copper-reports-strong-mostaza-copper-silver-recoveries.md","json_url":"https://www.share-talk.com/great-southern-copper-reports-strong-mostaza-copper-silver-recoveries.json","category":"Mining","categories":["Mining"],"tags":["Cerro Negro","Chile","COPPER","diamond rigs","Especularita Projects","Gold","Great Southern Copper","GSCU","La Serena","Lithium","Mostaza Mine","R. Muñoz","Salar de Atacama","Sam Garrett","San Lorenzo"],"featured_image":"https://i0.wp.com/www.share-talk.com/wp-content/uploads/2026/09/0c769ba5-5402-45b4-a2d5-f8675eecf43b.png?fit=1727%2C911&ssl=1","format":"news","language":"en-GB","content":"**Great Southern Copper plc (LON: GSCU)** has reported encouraging preliminary metallurgical results from its **Mostaza copper-silver deposit in Chile**, with recoveries exceeding **90% for copper and 85% for silver**.\n\nTesting on high-grade material averaging **5.09% copper and 279g/t silver** produced a concentrate grading around **27% copper and 1,414g/t silver**, using a conventional flotation process.\n\nThe company said the initial results indicate that standard sulphide flotation could provide an effective processing route for Mostaza, while further optimisation of grinding and regrinding could improve recoveries further.\n\nMineralogical work confirmed **chalcocite as the dominant copper mineral**, accounting for roughly 78% to 83% of copper in the tested samples. This helps explain the deposit’s high copper grades and favourable flotation response.\n\nBy comparison, initial leach testing achieved copper recovery of just under **50%**, significantly below the flotation results, reinforcing flotation as the more promising processing route at this stage.\n\nGreat Southern plans further metallurgical work using drill-core samples across a broader range of copper and silver grades as part of its **Phase IV drilling programme, due to begin within the next month**.\n\nFor investors, the main significance is that Mostaza has now shown both **high-grade mineralisation and potentially strong metallurgical recoveries**, two important ingredients for future resource and economic studies. However, these are preliminary sighter tests on selected high-grade material, and broader drill-core testing will be required before recoveries can be considered representative of the deposit as a whole."}