Domestic Production and Use: The value of usable ore shipped from mines in Minnesota, Michigan, and two other
States in 2002 was estimated at $1.2 billion. Eleven iron ore production complexes with 11 mines, 8 concentration
plants, and 8 pelletizing plants were in operation during the year. The mines included 11 open pits and no
underground operations. Virtually all ore was concentrated before shipment. Eight mines operated by five companies
accounted for 99% of production. The United States produced 4% of the worlds iron ore output and consumed about
6%.
A large portion, about 475 million tons per year, of world iron ore production is exported because much iron ore is not
consumed in the country in which it is produced. Australia and Brazil, for example, rank first and second, respectively,
in world production (Fe content) but 6th and 15th, respectively, in pig iron production (China produces more ore than
any other nation, but its ore is low grade). The vast majority of exports are seaborne.
Iron ore is the only source of primary iron.
Mine production
2001 2002e
United States 46 50
Australia 180 190
Brazil 210 220
Canada 29 35
China 220 230
India 79 80
Kazakhstan 14 16
Mauritania 10 10
Russia 83 88
South Africa 35 37
Sweden 20 20
Ukraine 55 60
Other countries 78 80
World total (rounded) 1,060 1,100
As you can see the USA Iron production is only 4.6% of the world production, as a matter fact USA need to import Iron From Canada, 49%; Brazil, 38%; Australia, 5%; Venezuela, 3%; and other, 5%.
The russian production is only a 8% of the world production.
http://minerals.usgs.gov/minerals/pubs/commodity/iron_ore/340303.pdf
Do you still think that: "the simple truth is that the US indeed had those kind of resources, as did siberia"
Final thing, USA have too many natural resources, and it's no real. But it is your scenario and you can do as you please.