Los Cerros encouraged by metallurgical works at Tesorito Porphyry on Quinchia resource, Colombia

Los Cerros (ASX:LCL) reports it has received ‘encouraging’ initial results from metallurgical test work on the Tesorito Porphyry at its Quinchia Gold Project, located in central west Colombia, 100km south of Medellin.

The company reports that the results show all mineralised units are amenable to a conventional cyanide leaching process to recover gold and silver.

The metallurgical test work program on the Tesorito Porphyry is being conducted by Ausenco and is nearing completion.

Tesorito is part of the Quinchia Gold Project and is a substantial contributor to the Quinchia Resource of 2.6Moz @ 1g/t Au.

Commenting on the results, Los Cerros Managing Director Jason Stirbinskis said: “The company’s current focus is on creating value through building confidence in its substantial bank of established resources at Quinchia.

The company’s current focus is on creating value through building confidence in its substantial bank of established resources at Quinchia

These encouraging met’ test results add to that confidence and are an important step to building a PEA (Preliminary Economic Assessment) around the Quinchia Gold Project’s potential production scenarios.”

Los Ceros is concluding the first round of Tesorito metallurgical test work as a key workstream required to feed into the Quinchia Gold Project Preliminary Economic Assessment (PEA).

The program involves five composites representing the main mineralised domains at Tesorito.

While optimisation studies are expected to make improvements on the following parameters, Los Ceros is reassured that Tesorito mineral processing performance is likely to be typical of high gold/low copper porphyry ores.

The first tests suggest:

  • 97% recovery of gold from saprolite and 87% from other units, derived from 24 hour whole ore gold leach tests
  • an optimal grind size of p80 ~75micron which is fine grind and typical of porphyry gold ores
  • there are no appreciable benefits in including a gravity beneficiation step, allowing elimination of this process step in the tests
  • silver recoveries and commentary on potential processing pathways remain pending
  • deleterious elements such as arsenic, mercury, organic carbon and soluble copper are all low and of no processing concern

The company reports that the conventional process flow of crush/grind, cyanide leach and carbon absorption for Tesorito mineralisation is simpler than the pathway described in the Miraflores DFS3 which uses a similar grind size but includes both gravity and flotation stages.

While there is now insufficient information to comment on optimising of processes across both feedstock sources and any potential configuration of a combined optimised process flowsheet, test work conducted as part of early feasibility programs suggests Miraflores material is amenable to the Tesorito process pathway.

The Quinchia Gold Project is part of the Mid-Cauca Gold belt which hosts many multi-million-ounce discoveries.

The project has a JORC-compliant Reserve of 0.46Moz within a JORC-compliant Resource of 0.84Moz at Miraflores, 1.3Moz at Tesorito and 0.46Moz Inferred Resource at Dosquebradas for a total Quinchia Resource of 2.6Moz.

In addition to these gold deposits the 10,500ha Quinchia Gold Project contains significant exploration targets including Chuscal and Ceibal.

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Written By Adam Orlando
Mining.com.au Editor-in-Chief Adam Orlando has more than 20 years’ experience in the media having held senior roles at various publications, including as Asia-Pacific Sector Head (Mining) at global newswire Acuris (formerly Mergermarket). Orlando has worked in newsrooms around the world including Hong Kong, Singapore, London, and Sydney.