A single flotation test was performed on a 2-kg subsample of each of the gravity tailings. The samples were treated with potassium amyl xanthate and methyl isobutyl carbinol at a natural pH for 10 minutes. Under these conditions an additional 70.1% to 93.1% of the gold was recovered.
Amex said that direct cyanidation of the gravity tailings may recover gold and silver as well as does flotation.
The flotation test was performed on half the flotation tailings. The slurry was reground to 70% passing 90 μm and leached in a bottle roll for 48 hours at pH 10.5 to 11.0. Cyanidation as tested gave excellent results, recovering 79.0% to 96.7% of the gold in the tails.
Eldorado Gold (TSX: ELD; NYSE: EGO) recently spent C$15 million on charity flow-through shares of Amex and now holds a 9.9% interest in Amex.
