In the past fifteen years, the copper industry has been undergoing extensive change. The large copper producing companies in the U.S.A. and Canada, for example, Anaconda, Kennecott, Noranda, and others, have established modern research facilities equipped with up-to-date, expensive apparatus and staffed with high-caliber metallurgists. One of the research problems assigned to these laboratories which was given high priority was a study on pollution abatement in copper production. About that time, it was also realized that chalcopyrite was the most abundant copper-bearing mineral. Consequently, a great deal of research effort was directed towards exploring new methods for extracting copper specifically from chalcopyrite without polluting the environment.