Hi, i Ripped most of my games with Cleanrip, but what is the BCA File for?
I'm pretty sure it just tells you that the dump happened. You don't need it to run your game.
The BCA is used for copy protection on GC discs. It's not "really" part of the disc which is why CleanRip outputs it to a separate file. Unless you want to burn the dump back to a real GC disc, you don't need it.