Advances in Gold and Silver Processing
68 ADVANCES IN GOLD AND SILVER PROCESSING increased to 50 kg per tonne. Highly refractory ores might require over 100 kg per tonne to yield more than 83 per cent gold by cyanidation. Sawyer and Hendrix (1988) had investigated the effect of sodium hypochlorite on the gold extraction from a carbonaceous ore in Nevada by heap leaching.