"The Mole" was the informal name of a type of mining vehicle used throughout the Federation in the mid 23rd century. It was equipped with a large forward phased energy drilling array, and had multi-terrain treads in addition to maneuvering thrusters and magnetic plates to navigate in low-gravity environments.
Montgomery Scott learned how to operate and maintain such vehicles early in his Starfleet career, when his ship ferried a group of miners to the new colony on Rigel XII. Later, in 2263, he got to help operate a Mole carried aboard the Starfleet Corps of Engineers ship USS Lovell while excavating a cave-in at Outpost 5. Scott later removed this Mole's flow regulator in order to maintain emergency power on the Outpost. (SCE eBook: Foundations, Book One)