There will be situations, where it is not feasible to build a whole outpost on an asteroid - maybe it is a very small one or would need to carry a lot of resources over to get an outpost maintained.
For those cases is could be possible to have dedicated mining ships, which are equipped with simple mining tools. Those ships could fly to the asteroid, land there, mine a little bit and bring back those ressources to their main asteroid.
This will be far less effizient than having big drills on the surface, but may be a good way of farming very small asteroids.
What's your opinion about that?