Fuel on board = 20,959 kg
About 2300kg of that would have been carried in a hold tank (Auxiliary Centre Tank), which at the time of the accident would probably have been empty. The centre tank would still have been about 80% full. The aircraft would have burnt at least 3000kg in the first 30 minutes.
That hole in the APU firewall Tyler showed looks very suspect.
Maybe it happened during ground impact.