How iron ore is mined
Iron is mined more than every other metal put together. Almost all of it ends up as steel.
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The short version
Iron ore is rock rich in iron oxides, dug from huge open pits. The best ore can go straight to a blast furnace. Poorer ore, such as the banded rock called taconite, is crushed to powder and passed under magnets to pull out the iron, leaving a quartz-rich waste behind. Nearly all of it becomes steel.
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Blast and dig the pit
Crews drill, blast and haul away the rock. Alongside the ore comes a lot of waste, both the bedrock above it and the unwanted minerals mixed into it. Rich hematite ore can be sold almost as it comes out of the ground.
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Crush and screen
Lower-grade ore is broken in stages, first coarse crushing and then fine grinding. Magnetite-bearing rock has to be milled to a very small particle size before the iron grains let go of the quartz around them.
ground to 32 to 45 micrometers
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Pull out the iron
The powder is passed under magnetic separators, which lift the magnetite away and leave the quartz behind. Hematite is denser than the rock around it, so it is separated by sinking it in a heavy slurry or by froth flotation instead. The result is a fine powder called fines.
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Dump the tailings
What the magnets leave behind is mostly quartz, which is chemically inert. It is stored as a slurry in regulated settling ponds. Every ton of concentrate leaves between 2.5 and 3.0 tons of this waste.
Worth repeating
- About 98% of mined iron ore is used to make steel.
- Taconite is rolled into pellets about 10 millimeters across that are about 65% iron, then fired hard so they survive the trip to the furnace.
- Taconite is the North American name for banded iron formation, a rock made of thin layers of iron oxide and silica.
Where it comes from
Ranking and Brazil's 16% share as given in the Wikipedia iron ore article; Brazil produced 440 million tonnes in 2023.
Where it goes next
Iron ore feeds 6 lines directly and reaches 264 things in total.
Further down the line
Keep walking
Sources
Cite this page: "How iron ore is mined." Assembly Line, 2026-11-03. https://assemblyline.org/make/iron-ore