Columbia subject headings:
Mineral industries--Portugal.
Mineral industries--Rome.
Mineral industries--Spain.
Portugal--Antiquities.
Spain--Antiquities.
Harvard subject headings:
Mineral industries--Portugal--History.
Mineral industries--Spain--History.
Mining engineering--History
Princeton subject headings:
Mineral industries--Portugal--History.
Mineral industries--Spain--History.
Mines and mineral resources--Portugal--History.
Mines and mineral resources--Spain--History.
Portugal--Antiquities, Roman.
Romans--Portugal.
Romans--Spain.
Spain--Antiquities, Roman.