Positive Metallurgical Testing Results At Cangrejos Project
VANCOUVER - Lumina Gold Corp. has received positive results from the latest metallurgical testing program conducted on its 100% owned Cangrejos gold-copper project located in southern Ecuador. The test results were the second round of metallurgical testing completed by the Company on the Project and demonstrated that the mineralized material can be processed by conventional industrial techniques.
Flotation combined with gravity concentration can be used to recover 83% of the gold and 87% of the copper into saleable concentrates. These results demonstrate a 4% improvement in the copper recoveries and similar gold recoveries when compared with the 2015 testing. The results also demonstrate that cyanidation of the gravity concentrates and flotation cleaner scavenger tails is not required in the flow sheet, which was the most favourable recovery method during the 2015 testing. Alternatively, whole-ore cyanidation can be used to process the mineralized materials to recover 90% of the gold in dore, but no copper is recovered.
The composites were prepared using 870 kilograms of quartered drill core collected during the 2017 drilling campaign from eight different drill holes and represented high grade and low grade mineralized materials from the Project. The Master Composite contained 0.25% copper, 0.96 grams per tonne gold, 0.6 grams per tonne silver and 20 ppm molybdenum. Gravity concentration tests, followed by lock-cycle flotation tests on gravity tails, were performed. The gravity concentrate contained 39% of the gold and 12% of the silver. The gravity concentrate assay was 143 grams/tonne gold and 31 grams/tonne silver. The flotation concentrate contained 44% of the gold, 87% of the copper and 67% of the molybdenum. The flotation concentrate assay was 43 grams/tonne gold, 21% copper and 0.2% molybdenum. When the molybdenum content is high enough the production of a separate molybdenum concentrate may be warranted. Comminution tests indicate that the materials have average Bond Ball Mill work index and SAG Mill specific pinion energy values of 17.7 kWh/mt.