Not really a whole lot to talk about on this one given the dearth of public information. And that is unlikely to change in the near term or possibly at all. Silos are notoriously abused so structural failures are not that uncommon. That said at a guess I'd think this might be a foundation failure given its proximity to the river.
Not the first time recently that the company has has incidents. In the dust explosion incident reported below they were very lucky not to have deaths. (Note, I have no reason to believe the company has any systemic structure/safety issues here. Could just be 'bad luck'.)
An those are just the incidents that hit the news. One resulted in a death the other closed a highway. These incidents are certainly not uncommon. And yes non uniform radial loads can result in failure, I've seen distortion caused by that.
This happened a little over 4 years ago in Algeria. A coastal storm hit and the silo were evidently not suitably design for the wind pressures they experience. At this point they were brand new and some still under construction. Though that shouldn't have affected ulitmate strength the wind rings were installed and are visible.
Early indications are that that this is a silo structural failure not a foundation failure. It is difficult to assess due to area still being inaccessible.
Silos of this size are generally not fabricated in Australia. They are normally imported and it is believed that these ones are no different. And there has been a long history of inadequate design of imported silos. They are expensive "commodity" item so there is a race to the bottom not unlike "PEMB" in NA or "kit sheds" in Australia.
The clean up is continuing though occurring at a slow pace due access difficulties and safety concerns (Australia has particularly stringent OH&S rules).
The area is shown below. Mobile crane access is limited. Personnel access is limited. Australia is a small country and I don't think water borne cranes are a readily available item.
