Originally posted by Damnion:

There are dungeons. Are you using an older map? I've heard they might not generate properly even if you haven't explored the mistlands yet.

If he got structures at all it's working, im using an old map/save and went to one and i'm finding them. Probably just got unlucky. My first Infested Mines didn't even have a single core in it lmao, and it was the only mines in that mistlands. Thankfully the other ones near it on the other side of a plains was absolutely loaded with them.

So RNG. I do wish though they'd update how dungeons generate so you wouldn't end up with nothing in a biome or no essential mats when you enter one.