It might be very rare under those circumstances.
AnonyMods adds a lot of ores with quite high relative priorities. And peace mod ore has quite low priority. I'd recommend one of radar mods to help with searching by using radars.
In quick test I found one alien ore patch in 2kx2k area so it might be hard to find.
Few high grade radars or upgraded ones in BigBrother placed in map corners should have some chances of finding a patch. It's purple on map - color similar to oil wells.