Bucknell described using a 72-ton machine for harvesting water from ice on the moon in a presentation from the 2017 Icarus Interstellar conference.
The best estimates indicate there is 18 billion tons of water on the Southern pole of the moon. It would best be harvested using microwaves.
A large ice harvesting machine could be delivered to the moon using a SpaceX BFR or Bucknells proposed air-breathing nuclear thermal rocket. The SpaceX BFR would need to have a refueling in high earth orbit.
Bucknell then describes the creation of a space station with most of the mass being water and ice. 89 trips of a nuclear thermal rocket could fill up a 2000 person space station.