World Generation Manager Mod allows force re-generation of chunks using other mods.
How it works:
This mod creates a config file. By default no mod ares are regenerated, because it isn’t activated. Under the category “regeneration” there is a list of all WorldGenerators, you can disable and enable what ever you want. If you enable a mod’s Worldgenerator in the config ALL ores and other World generation stuff (e. g. marble deposits from redpower) from that mod is regenerated in all Chunks you visit.

Detail and Download here : World Generation Manager Mod

Homepage: Mods for Minecraft