Altamira says thiosulphate leach recovers 92% of gold

Altamira Gold (TSXV: ALTA; OTC: EQTRF; FSE: T6UP) says metallurgical tests using a thiosulphate leach on drill core composite sample have a […]
Quartz feldspar porphyry host rock drilled at the Maria Bonita target in Brazil. Altamira Gold photo

Altamira Gold (TSXV: ALTA; OTC: EQTRF; FSE: T6UP) says metallurgical tests using a thiosulphate leach on drill core composite sample have a 92% gold recovery rate. The samples came from a sample of primary mineralization form the recent Maria Bonita discovery at the Cajuerio project in Para state, Brazil. 

SGS Australia and CSIRO laboratories tested the use of Clean Earth Technologies’ proprietary thiosulphate leach as a non-cyanide approach to treating gold ores. Clean Earth is commercializing the method developed by CSIRO. 

The test included grinding the sample to 80% passing 75 microns and then placing it in an agitated thiosulphate leach. After 24 hours, 92% of the gold was recovered. A cyanide leach test was conducted in parallel using the same grind and leach time yielded a gold recovery of 91% from an identical sample from Maria Bonita. 

The Cajueiro project is a historic placer producer of 250,000 oz. gold in the 1980s and 1990s. It is one of the largest placer camps in the Alta Floresta Belt. The project has an NI 43-101 compliant oxide resource of 850,000 indicated tonnes grading 0.92 g/t gold and 1.7 million inferred tonnes at 1.12 g/t. There is also a sulphide resource of 4.8 million indicated tonnes at 1.04 g/t and 11.0 million inferred tonnes at 1.29 g/t gold. Altamira acquired the property in 2016. 

Several mainly untested gold-in-soil anomalies occur within a short radius of the Cajueiro resource and include Maria Bonita, Sossega and Novo Sonho. Maria Bonita is the strongest target with a geochemical anomaly covering an area compatible in size to the entire Cajueiro mineral resource area. 

Learn more at www.AltamiraGold.com.

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