It's quite rare, but I do occasionally get 4 hits from the mine...

I've heard tales of getting five parts at once, but never successfully done it myself...

I have a little collection of screenshots, where I was lucky at mine :)

You know in theory, one could get 12 parts in one go... But that would require every tap to be a successful hit. It is possible (unless there's something that I'm not aware of), but you'd have to be the god of luck to do it...

I'm not 100% sure, but I thought that 5 parts is the maximum number for every approach.

This is the first time I've heard of that (that's why I said "unless there's something that I'm not aware of"). There's nothing on the Mining page about that though (unless I'm blind), so maybe could someone else confirm this?