Topic
- Buildings 3
- Cargo ships 3
- Factories 3
- Mining machinery 3
- Photography of railroads 3
- Photography, Close-up 3
- Railroad rails 3
- Sheet-metal, Corrugated 3
- Steamboats 3
- Steel ingots 3
- Taconite 3
- Abandonment of property 2
- Basic oxygen furnaces 2
- Ores 2
- Power shovels 2
- Railroad cars 2
- Reflections 2
- Slag 2
- Steel --Metallurgy --Oxygen processes 2
- Taconite --Minnesota --Mesabi Range 2