Turbine D is your man here. He should be working for the ATSB.
Lets not forget that this was a T972 on very heavy work cycles esp out of LAX ro Oz. RR made a severe error in an oil pipe bore. Qantas are persuing them in court.
This engine was not a T970 or a T1000.
Turbine D is one of the very few people who had the quals and tactile experience to assess this engine failure.
And as for No. 1 engine running on a for a full hour .. what can you say..God was with them.