>>248039There are two major ways of getting iron ore, by mining it out of rock and stone, like most other metals, OR, getting "bog iron". "Bog Iron" is just a catchall term I'm using for this post, as it appears in places other than bogs, and there's probably some fancy geological term for it.
There are three basic ways of finding this "loose" iron.
Some bacteria basically "eat" iron (or more so they use iron to breathe like we use carbon, consuming iron and "breathing out" iron oxide, rust). They "breathe out" iron oxide (rust), and this accumulates. This tends to form pebble to egg sized granules that can be dug out of bogs, swamps, and hell, just under the soil. They're too small to really be of any major industrial use, but they are a renewable resource, and every generation or so, you can go out and turn over the same bog and get a lot of ore (for a single person, that is).
The other way is to find larger, more "rocky" iron. These are on beaches, under the soil, etc. They can be much bigger than the "bacterial" bog iron, but they aren't renewable.
The third way, is to find magnetite sand. Iron has several oxides ("rust", which is red, Magnetite, which is black, maghemite, which is light brown, etc, etc). Magnetite is the most magnetic natural material, so one way of getting it is by just passing a magnet over it. It's present in sand, forming the little black grains, black streaks, or occasionally, entire beaches (although sometimes the "Black sand beaches" are actually black volcanic glass, not magnetite).
That guy is Finnish, and Scandinavia has a ton of deep rivers and fjords and such. He basically dredged the bottom of the river, and pulled up rocks. If a magnet was attracted to them, even ever so slightly, he kept it. If not, he tossed it. Although not all ores of iron are attracted to magnets, some are.
