Your intrepid reporter froze his ass off for an hour and a half to bring you these important images. It was a very slow process, and is ongoing. They have to be done by 5AM to reopen the road, but I didn't have the stamina/layers.
This disc is the engine that the cutting blades attach to. The other piece on the truck, which I think goes behind this one, goes into the hole on Monday night. The cutting blades go on some time later. "Everyone shows up for that", said the foreman. "Those are really cool."