Turbine blades or turbine disc....
Looking at the photos on Flight Global it looks more like a large bit of turbine has exited the engine, in the 3rd photo you can see the core engine turbine casing flange, it should normally have a fairing on it. If only a turbine blade had exited there would normally just be a small blade sized puncture
Pictures: Qantas 747 uncontained engine failure-31/08/2010-Washington DC-Flightglobal.com
4 Engine A/C, big deal or not....
The same engine type (RB211-524) is fitted to the B767, ETOPS a/c, and the turbine architecture is the same. And most of the Trent family is similar too.
Similar events....
Edelweiss A330 (Trent 700, shares the HP/IP turbine of the 524) ex Miami October 2003. Engine lost substantial piece of the IPT disc due to overheating in the HP/IP turbine bearing area, due to oil vent tube coking. Overheating caused the IPT disc rotor arm to crack and fail see:
An Incident With A Edelweiss A330 Departing MIA — Civil Aviation Forum | Airliners.net