TABLE OF CONTENTS Copper sulfide ores with medium pyrite content contain up to 50% sulfides, the average sulfide content is about 15% Fe 2S. Some of these ores may underline porphyry copper deposits known as a high-pyrite hypogene ore type. In other cases, they appear as copper scarns (Antamina-Peru copper ore) or stringer ores, which sometimes are pockets or lenses of massive sulfides (e.g. Crandon, USA and Woodlawn, Australia). The stringer ores usually contain small quantities of zinc or both lead and zinc (i.e. 0.2-0.4% Zn and 0.1-0.2% Pb).
Primary copper-gold ores may contain between 6% and 50% pyrite and primarily contain chalcopyrite. In some cases, bornite and covellite may be present in the lower portion of the ore body (Batu Hijau, Indonesia) or enargite (El Indio, Chile). In other sulfides, these ores contain pyrite and sometimes arsenopyrite and pyrrhotite. The gold in these ores is represented by electrum or as copper auride. In most of these ores, a portion of gold is contained in pyrite.
Ores with an elevated amount of arsenopyrite belong to a group of arsenical copper-gold ores. The characteristics of these ores is that the gold is encapsulated in all sulfides (e.g. arsenopyrite, pyrite and chalcopyrite) and sometimes also in quartz.
Partially oxidized copper-gold ores, such as those from Red Dome (Australia), belong to a group of refractory ores and also contain high clay. The gold in these ores is also found in iron hydroxides and oxide...
