Protip: It is inefficient to ever mine them. Period. If you want money then go somewhere else. If you want exp then this is a decent spot just remember to peity them. Edit: Also, the amount of lp they have is one of the reasons they are good, less overkill loss. Also, your str and att levels will hold you back at any spot. These guys have almost no defense so it shouldn't be any more then they would at say armored zombies.