Resources of the pre-modern world...
- Lead
- Fresh Water
- Salt
- Tin
- Bismuth
- Zinc
- Iron
- Copper
- Mercury
- Nickel
- Coal
- Silver
- Gold
- Wood
- Tameable Animals
Which resources where?
Lead and Silver are mined together and Lead is by-product of Silver Mining.
Copper is usually mixed with Tin or Zinc, but can be found by itself.
Mercury is used as a medicine and in mining of Silver.
Zinc can't be found by itself and was undiscovered as it's own thing till much later. In the smelting and smithing process an alloy turned up that was valuable.
Bismuth and Nickel were seen as "cheap" or worse versions of the other resources and found with them. I forget which though.
Salt can be found virtually every where, but Salt Mines largely exist where Glaciers used to be... which is everywhere pretty much.
Tin, Copper, Iron, and Gold are all found on eluvial plains.
Lead, Zinc, Bismuth, Mercury, Silver, and Gold are found in Volanic areas (not volcanoes).
Coal of different qualities is found in various places so there isn't a good answer for where it is other than define where swamps were 250 million years ago and thats where it will be today on those land masses. Also there are things called peat bogs that produces not very good coal in less time. You can also make it from wood. Hard to pin down, but mountains and swamps is where you'll find most coal mines
Fresh Water is dictated by your landscape, as is wood.
Tameable Animals is the difference between Cities and Nomads/small villages. I have not done much looking into this aspect but I need to soon.
So where to put things? Basically, have to work the plate tectonics out so that you can figure out where the 3 type of sediments go. And then you can just randomly distribute all types that go in that sediment, keeping in ming that the only things that were Salt, Mercury, Copper, Iron, Gold, and Silver... of which you can say there were "Copper-Iron" "Gold" "Silver" "Mercury" and "Salt" mines. distributed pretty much like so...
Aluvial area: "Copper-Iron" and "Gold"
Volcanic Area: "Silver" and "Mercury"
Everywhere: "Salt"
Since Salt is "everywhere" and important, you can just toss it as placing correctly and instead just use it for story purposes since humans need salt and it fairly common, but still, there is only so much any single place can hold so its a reason to war and such in the past, but it became so easily accessible by the middle ages in other forms that it's hardly worth mentioning.
Now the problem with placing any of the other 4 "accurately" is that any map that I have ever seen doesn't really help as it just has mines strewn about everywhere in any place that is considered to have these elements which indicates to me that mines are just where they are because that is where randomly, enough of the material was seen at that point that's where they started digging or they purposefully set up a camp there because it is secure and then just started digging till they hit something. Either way this means that 3 of the 4 is more or less just random. Mercury is however, as I understand it is found in lowlands and swamps due to how it gets pushed to the surface so there is some geology there at work, but where these things are also seems arbitrary to me, even though it probably isn't.
Things to note however...
Mercury limits Silver and Gold mining. How I don't know, but it's used in their mining so if you don't have Silver you can't mind those thus you're limited by it.
Salt limits your overall work force since if humans don't get salt they die.
Iron & Copper limits your overall military and production capacity due to if you can't get these materials you can't arm your soldiers/workers copitently.
So from that perspective you can simply define your nation by some math where the stronger they are the more of those mines must be under their control and just balance the equation to figure out how many should be in the region that a nation in your world controls. To do that is a whole other topic, but the startin point for that is that for a government to control a place, from what I have looked into, they must be able to deploy a unit there within a month. To trade with a place effectively, a trader must take no longer than 1 year to get there. From that, you can see how much you can control and trade... in other words, All mines must be within a month of travel of military deployment, and that military must have enough power to maintain it's control, either from resources inside it, or traded to it.
Hope that helps. It's a really hard question that I've never found any easy answers to and any answers that I did learn requires more and more knowledge about geology to answer 100% accurately.