Unless the rules have changed, or are different for these new superflat worlds than they are for default, coal doesn't spawn above 128 and iron doesn't spawn above level 63, I think it is. How deep is the tunneler's dream preset?
Private Mod Note
Rollback Post to RevisionRollBack
Village Mechanics: A not-so-brief guide - Update for 1.4! Added subsection on iron farming to the iron golems section. Only ten villagers required to spawn golems (down from sixteen)! Put to rest the "facing doors cancel each other" myth!
I made a mod that creates a 256 high cave dimension and faced a similar dilemma on how the ores should spawn, it is not much use to have 256 high cave system if all you do is mine the diamond layer so i am thinking that ores and such should not be Y limited.