Columbia subject headings:
Harvard subject headings:
Geology, Economic--Brazil--History.
Iron industry and trade--Brazil--History.
Iron mines and mining--Brazil--History--19th century.
Iron mines and mining--Brazil--History--20th century.
Iron ores--Brazil--History--19th century.
Iron ores--Brazil--History--20th century.
Steel industry and trade--Brazil--History.
Princeton subject headings:
Geology, Economic--Brazil--History.
Iron industry and trade--Brazil--History.
Iron mines and mining--Brazil--History--19th century.
Iron mines and mining--Brazil--History--20th century.
Iron ores--Brazil--History--19th century.
Iron ores--Brazil--History--20th century.
Steel industry and trade--Brazil--History.