I experimented a lot, and it doesn't seem that biome matters.
Putting mine in a mine is a bad idea, because it stops functioning each time you leave the mine. It also doesn't produce gold.
My mine in the far north, in Chaos biome, produces more diamonds than iron. I think somebody said that it happens in any place that's far enough north, and it doesn't have to be Chaos biome.
I have yet to make an experiment where mines are operated by differently-leveled beings, to see if stats matter.
I am not a moderator, so I don't know what they're thinking. If you're worried about it, you can report the comment to the moderators, and let them make the decision.