Is there a particular depth where one finds Iron ore? I only ask because I'm starting to wonder if I've somehow managed to worldgen a world without it. I've tunnelled far enough down to reach the first layer of caverns (10-15z), and had some mild !!fun!! in doing so, and the fact that I don't have access to iron and have only limited access to fuel increased said !!fun!! exponentially, so I'm a little wary of tunnelling any deeper if I don't have to.
Also, I checked the wiki, and apparently Bituminous coal isn't found until after the chasm (which I'm apparently yet to discover), but that's for the 0.23a version, and I'm using DF2010. Anyone able to confirm if this is still the case?
The 2d version was very, very different. Every map had everything, and all you had to do to get it was dig deeper into the mountain. In the current version most maps simply do not have most things. My current map, for example, has abundant zinc, lead, and the occasional silver. But no Iron, Copper, Tin, or Coal.
Thus the only metal on-map my weapon and armorsmiths can use is Adamantine, and that's not exactly the kind of thing you can use for 600 BS jobs training up your guy to Legend.
If I were you I'd focus on building a very good squad. Buy weapons and armor. Get them sparring. They'll be more then good enough to deal with goblin ambushers with minimal casualties, and each ambusher has at least a cap. Melt 10 caps and you have a bar of metal. It's called mining goblinite, and it's slow as hell but it works.
Also you don't actually need to breach caverns. In my current fort the only "breach" in the caverns is a water-source for my hospital, and only one Forgotten Beast has managed to use it.
Nick