If you haven't seen these... https://www.youtube.com/watch?v=NPXfA_h8EcY https://www.youtube.com/watch?v=aeDZhPhdndc
That's some good TV. Seriously, though, I'm more of a tractor-pan guy, but I have run some 627's. Only criticism I would have is when you're getting out of there empty, your foot should be nowhere near the back engine's go-pedal. All you're doing is pissing fuel away. Those are some big hunks of iron.
Why didn't those guys just break down the hill with empty machines and be done with it? I've busted down miles of sand dune with a 657 and never worried about loading a yard til I could get a good long run. A little hump like that you run the tailgate forward with the apron up and do your own dozer thing as you jump over the edge.
Looked to me like they were. The first trip they were loaded then they were just making circles.