Hey, no need to be like that.
I get snarky easily. I blame it on infiltrating human society a thousand years ago and convincing them that I was a god whose only sphere was that of vitriol. Now it's just kind of a habit, and people often get quests from village leaders to come and annoy me with sharp implements.
Sorry - it was a bit harsh.
Most maps I gen with it set to 100 have 20000+ iron, when you combine Hematite, Magnetite and Limonite.
See, that's what I was expecting, but the problem is that you're not guaranteed to get
iron. I had ~60000+ Cobaltite, and 0 (zero) Limonite/hematite/magnetite. Lots of gold, silver and tetra, though, so if I wanted a copper military, I'd have been golden (and silver)! (No cassiterite, though, so no tin, and no bronze.) This was sorely disappointing, and if I wasn't in the habit of busting out DFreveal at embark to plan a central staircase, I wouldn't have even known about it until later. I'm not planning to run this fort as a Goblinite Farm (and I'm not sure I have the patience for that) so I wanted some iron. Two more worldgens (and half-a-dozen embarks later) I started hacking RAWs instead.
Even with my changes (deleting cobaltite/cinnabar, which worked.. sorta) you're still not 100% guaranteed to get iron, because gold and silver and tetrahedrite are all metals (plural) that can be found both shallow and deep! The solution is definitely to add a chance of smelting iron from burning up cluster/vein stone that isn't normally an iron product, and then you're guaranteed to have SOME iron, even if it means you work a lot harder for it than just mining it out one bar per tile. (I'll probably put the "useless ores" to 100 percent so they function like iron ores, and then put other cluster stones to ~25% or so so they provide some useful product beyond colored stone.)
Now, that raises another question: Is it possible to control the effects of the smelting process in the RAWs so that on failure it returns the original rock (Yes, I
know that's not how real smelting works), and on success it returns the iron? I don't immediately see anything in the token list that offers this as a possibility. I'm guessing that's the province of custom reactions?