This is intended behavior. Minecraft resources(ores) generation is not realistic. Having no ores generated also eases the terraforming process for the builders.

Given that one of the mod features is listed as 'Ore spawning just below surface', could you point us to which config property in the generator needs to be flipped to enabled this?
I've played around with those settings but can't seem to find it either.

Was this issue (feature) ever resolved? How does one enable ore generation in T++?