The association of gold and silver with other minerals in flotation concentrates are shown in Fig. 7 and Fig. 8, respectively. From Fig. 7, 68% of the floated gold was liberated with free surface in baseline flotation concentrate, but it was increased to 85.3% in the flotation concentrate when free cyanide was present. Although the accuracy of detecting gold associations was not reliable in this study due to a very small amount of gold particles detected, it is suggested that some of the unliberated gold particles were depressed by free cyanide in flotation. On the other hand, silver association results were more reliable because a large amount of silver mineral particles were detected. Fig. 8 clearly shows that 63.1% of the silver minerals were liberated with free surface, and 16.9% were associated with pyrite in baseline flotation concentrate, whilst the silver minerals associated with pyrite were decreased to 9.3% in the flotation concentrate when free cyanide was added, indicating that silver-bearing pyrite flotation was depressed by free cyanide. Since free cyanide and cuprous cyanide showed the similar flotation behaviour in terms of Fe and S recoveries, it is concluded that cuprous cyanide species, mainly in the form of Cu(CN)32−, also depress the gold and silver carrying pyrite.