An asteroid mining robot, the dig is designed to land on an asteroid in swarms and scrape the surface with its strong paws. Since many asteroids are basically large piles of rubble, and opposed to solid rock, removing material from the surface is actually quite easy. The disturbed surface material will then be caught in large nets for transport to a refinement facility.
A few suggestions just for thought:
1) "Piton feet"--hydraulic cylinders on sides of leg ends to drive a sharpened piton into the rock.
2) Propellant tank(s) on top with thruster nozzles that allow it to thrust downward so when moving/digging it doesn't float away from the asteroid.
3) Underneath, mantis-like digging claws, a center mounted pile driver, laser cutter or circular cutting blade and motor for reducing/removing/cutting into rock.
4) Side-mounted antennas, swivel spotlights.