That is an interesting tweet. The same image was used in Mike's tweet on the 7th of May (Right hand side image) When you compare the two images, there are no changes. the vehicle is still parked in the same location there is no other changes in the image. Can we assume there has been no progress with the tailings dam since the 7th of May? It might explain why Mike mentions in the tweet in your pos. "Current waste mining is behind target for TSF wall lift"
