Cadia Tailings Failure - misleading info?

https://www.linkedin.com/pulse/cadia-mine-tailings-failure-digging-deeper-using-earth-adam-thomas Looks as though this was a known problem for at least a few months prior. Based on deformation data, visible cracking should have presented at the failure scarp well prior to dam failure. It's interesting that the failure area was left untouched in satellite photos - could this have been for tension crack or deformation monitoring?? I'm skeptical as to whether the first signs of failure were cracks that appeared earlier on the day... keen to hear thoughts from others