Attack vessels known as combat drills served as mining vehicles for the Shu-Torun Loyalist/Imperial Delving Fleet located on the planet of Shu-Torun. In the course of the War on Shu-Torun, the Sith Lord Darth Vader traveled inside a combat drill accompanied by his stormtroopers; however, Doctor Cylo, ostensibly an ally, intentionally damaged the vehicle, leading it to stray from its intended path and crash into a lithoporoite seam that lacked the structural integrity to bear the drill's mass. Consequently, the drill plummeted into a subterranean cavern, where it was met with an ambush by forces loyal to Cylo-V and the insurgent Baron Rubix. Vader's stormtroopers successfully defended the drill, aided by a unit of enhanced BX-series droid commandos also housed within the vehicle, allowing them to eventually rejoin the primary battle.