Columbia subject headings:
Harvard subject headings:
Copper mines and mining--Arizona
Copper mines and mining--New Mexico.
Gold mines and mining--Arizona
Lead mines and mining--Arizona.
Phelps Dodge Corporation.
Silver mines and mining--Arizona
Silver mines and mining--New Mexico.
Princeton subject headings:
Copper industry and trade--United States--Periodicals.
Copper mines and mining--United States--Periodicals.
Phelps Dodge Corporation--Periodicals.