One of the behemoths had a huge jackhammer it was using to break apart the boulder piles; another one had the regular 'steam shovel' arm.
I watched that one take a giant scoop from the river, then turn and dump it on the bank. Probably a hundred gallons of water poured out - then this huge boulder clunked down. It would have been fun to just hang out and watch. It brought back the kid in me!
We were also rewarded with some beautiful ice sculptures on the rocky cliffsides along the road.