That is not bad. Myself and one of my lead operators have done quarry slopes that were taller and just as steep. It was dirt, and no cable needed, but it was a long round trip with a wide track D-6H.
The Volvo backing up to dump I did not think was bad, until he gave it the last 4 feet or so. That seemd to me to be farther than he needed to go. I would definately want to have a truck new enough to be in great condition, but with enough hours on it to have the bugs worked out. I sure would not want to be hauling sticky material and dumping like that. That rock slid right out though.
The one I like best is the snowcat with the on board winch. I have seen some crazy slopes they run on held up with that cable.
Hats off to a couple of experienced guys putting their iron to the test.