Jacques McMullen

Adsorption of aurocyanide complexes onto carbonaceous matter from preg-robbing Goldstrike ore

Abstract Aurocyanide complex adsorption by naturally occurring carbon in Goldstrike ore has been implicated in a form of gold refractoriness known as “preg-robbing”. The aim of this work was to establish a relationship between the aurocyanide uptake capacity of Goldstrike ore carbonaceous matter and the preg-robbing behavior of the parent ore. The effect of varying contact time between the aqueous gold–cyanide and the carbonaceous matter on the uptake of aurocyanide complexes was also investigated. In column adsorption experiments, the adsorbed gold concentration from 100 mL of a gold–cyanide solution depended on the flow rate of the solution. The concentration of adsorbed gold increased with solution flow rate, reaching a maximum concentration at a flow rate of approximately 0.05 mL/min. As solution flow rate increased to more than 0.05 mL/min, the concentration of gold adsorbed on the carbon decreased. Desorption of adsorbed gold into 75-mL sodium cyanide solution also depended on solution flow rate. Maximum desorption of gold occurred at a flow rate of approximately 0.14 mL/min. The gold adsorbed at the lowest and highest flow rates was more slowly desorbed than the additional gold adsorbed at the intermediate flow rates. The concentration of gold remaining on the carbon after desorption at 0.14 mL/min correlated to the amount of gold adsorbed at the highest and lowest flow rates in the adsorption experiments. This amount of slowly desorbed gold correlated to the preg-robbing behavior of the ore, whereas the amount of additional adsorbed gold (i.e., gold adsorbed at intermediate flow rates) was similar for all of the ores. For all of the carbonaceous matters studied, the concentration of gold sorbed in both batch and column experiments increased after autoclaving.

Process control advance in gold processing

Abstract The evolution of automation and process control has forever changed the way gold processing plants are operated. Over the past twenty years, from being fully manual, plants are, nowadays, virtually operating on full automatic mode. An overview of the process control evolution is presented along with the challenges currently faced which, when resolved, will allow turning to reality the future vision proposed on how plants are likely to operate.

Gold-copper ores processing cyanidation optimization of flotation residues

Abstract Typically, economic optimization of Gold-Copper ore processing presents challenges. Barrick’s Bousquet II ore is a good example where many processing units such as gravity, flotation and cyanidation are required. Cyanidation process optimization and its inter-dependence with flotation are discussed in detail. Real-time integration of the cyanide control strategy has allowed a reduction of cyanide consumption of over 55% since 1994, while maintaining or improving metals recovery. A detailed analysis of the cyanidation control strategy is presented. This robust control strategy is a key building block in optimizing the overall economic return of the plant.