That's a Rahco surface miner. Basically, it's just like an asphalt milling machine, and pulverizes the material it's being used on, as well as loads it out at the same time. Typically, they are used for thin seams of material, or large flat lying deposits.
It has to stop periodically to exchange trucks under the conveyor, but only really has to pause for a couple seconds while the next truck spots in. In a thin seam, a shovel will have to move too much while loading, and can't easily shave off a thin layer like this machine can.
While the machines are a bit different, here's a video of a surface miner being used on iron ore in Australia. Same general concept, but a slightly different machine design, as the Rahco uses a front mounted cutting drum.
One really nice advantage of a surface miner, is that you don't need a primary crusher. These don't need blasting either, though they aren't made for extremely hard rock.
Basically, they have some applications where they excel, and others where they are not practical.