I was a little surprised that the earlier thread with the video was locked. The rollover was a tragedy, but the video was not gory. We talk about the details of accidents on this forum, so I don’t see how that is much different from a video showing a dozer roll, but no actual human involvement. And the video does raise some interesting questions about how the accident happened and how it might have been prevented.
Some have wondered if the accident was staged in some way. If you stop and start the video several times during the roll sequence, and watch close, I think it conveys a more graphic depiction of the roll and disintegration of the dozer. In the end, the blade flies off, sailing high into the air. At the very end, you can see one track (just the chains and grousers) running free down the hill like a rolling tire. Interestingly, it does not look like the ROPS came apart. The operator may have not been belted, and may therefore have been thrown out at some point. But if the operator had been wearing a seatbelt, I wonder if he might have survived the roll, assuming that the ROPS held together.
I get the impression that rolling those rocks might have been just a little horseplay. What other purpose could there have been? Even if you had to get them removed from where they were, sending them for what might be over a mile roll seems a bit careless, considering that some person might somehow end up in their path.
The people doing the video do seem rather mysterious. If rolling the boulders was just horseplay the video people might have been in on the plan and taking video to show the spectacular results. But their reaction to the dozer roll does seem almost as though they do not realize what is happening. I think the missing video might just be coincidence. They might have decided that there was no point in running the video until a rock came down, and just then, the dozer came down.
I speculate that the operator got the dozer so steep that it could not back up. With the weight of the blade, and the steep downgrade, the tractor would have been front-heavy. The tracks would be loaded up on their idlers, and as they slipped, they would dig down and worsen the angle. Slipping the tracks, trying to back up, would bounce the dozer around on the loose, gravely / rocky soil. Once the machine was up on its tiptoes, it would be easy for it to swing/fall to one side or the other. And once that happened, it would be sideways to the slope, and the momentum from the swing would begin the side roll.
It would be interesting to learn the actual details of this accident.