Description of the Bug
Railcraft ores only spawn in small areas. I looked for a long time for zinc and I looked with x-ray: In a map that is already hugely genrated, there is only a zone of some chunks that has railcraft ores.

To Reproduce

1. Start a new World with Railcraft and an x-ray mod.
2. Go in spectator, set the x-ray on zinc or tin.
3. Search in the deep for a long time, and find something like in the photos.

Expected behavior
Railcraft ores should be generated balanced all over the map

Screenshots

Logs & Environment
My logs, I don't know if it can help

Latest:
latest.log

Debug:
debug.log

#1953, #1896, and almost certainly others.

But isn't it a bit too rare? I searched a very long time in spectator. In survival it should be nearly impossible