No QF A330's can dump fuel.
Its an option on the -200 (the ones with centre tanks) but the most I ever saw in one was about 5 tonnes flow LAX to AKL. May be useful for EK if they're doing ultra long haul in them, but once you start loading that much fuel in the 330 your available payload quickly shrinks. Its been a couple of years but i'm pretty sure main tanks held 69 or 79 tonnes, enough to go to beijing easily, and provided the overweight landing is fairly smooth the engineers inspection is a quick one.