Nice video.
I would be intrested to know what is going on ( apart from the obvious.... he loading a roll on off
)
I take it the cofferdam is not watertight which is why its not pumped out.
The size of some of those rocks and your previous comment, I take it he is having to use a breaker.
What concerns me is if the cofferdam was built/installed and then infilled so the excavator can get out there to work ( look at ground outside the steels )
then is he not pushing his luck spinning 180* while sitting on that edge. It might be solid rock he is digging but that is below water, what about the made up ground he is sat on?
With reference to the time spent draining the bucket. If you look in the back of the truck it appears to have material ramped against the rear door suggesting to me that the truck has to go on the highway and somebody does not want a big fine or cleanup bill for leakage.