Autonomic Crust-piercer
this piece of mining machinery uses a huge, cone-shaped gouge to break through a planet's crust in order to reach the ores below it. The crust-piercer is essentially a long, solid pole. The cone is studded with durasteel teeth, and the entire machine is moved about on huge treads. This configuration allows it gain a great deal of momentum before plowing into the earth, at which time the grinding of the cone makes quick work of the surrounding strata.