Gangue rejection responses for a variety of gold ores

Gangue rejection, resulting in an increased head grade at a higher net throughput (or, smaller plant footprint), and the creation of dual products, eg high grade and low grade, for alternative processing streams are two treatment options being investigated to turn otherwise uneconomic ores into reserves. Eleven gold ores have now been assessed for their potential for rejection of gangue by gravity separation using the gangue rejection amenability test (GRAT). The samples represent a variety of gold ore types, from several continents and gold producers. Additionally, two ores have been processed using four different crushing modes to characterise the influence of crush-type on liberation. The resulting GRAT database can be used for benchmarking and to determine the optimal gold loss vs mass rejected response for each ore given the influence of elemental deportment as a function of size and density based separation.