Copper sulphides

Ores containing gold associated with copper sulphides minerals which affect process selection or operating conditions belong to this group. It is relatively uncommon for gold to be associated solely with copper minerals and there is almost always some pyrite present. In base metal sulphide processing gold generally reports with copper minerals, e.g. chalcopyrite or bornite, in process streams. This can be attractive from a metallurgical point of view, as there is some selectivity against pyrite and the possibility of selling a gold reach copper concentrate by for which a credit is received. Although gold grades in copper ores may be low, gold production as a by product of copper is relatively large due to the high tonnages of material processed. About 80% of by-product gold comes from copper ores; the remainder being accounted for by Pb-Cu-Zn ores.