I've tried several things that fixed the issue for other people before but no matter what I do I can't get Zinc, Yellorium, or any other non-vanilla or Thermal Foundation ores to spawn. There are a few exceptions. I can find Cobalt and the other Nether ore (forgot the name) but for the most part it's only Thermal Foundation. The solutions I tried can be found here: https://github.com/FTBTeam/FTB-Revelation-2/issues/234 and for the Yellorium he links to a fix he found prior. However, neither of these worked. I went a few thousand chunks away by using a tp command just to check and then mined for an hour. Nothing.