Which of these asteroids is easily accesible from an orbit around ceres for the purpose of mining?
No idea but why spend a few billion to dig out a ton of ore that you can get for few hundred bucks on earth ?
Metals that are easily magnetised are the ones that can deflect a magnetic field so a large chunk of iron or steel would be the recommended choice. Horseshoe magnets often come with a keeper which controls the flow of the magnetic field
some supplies, including bismuth and antimony, are repelled by using a magnetic container, having permeabilities decrease than that of loose area; those supplies are observed as diamagnetic. The magnetic action which characterizes diamagnetic aspects, the magnetic moments of which tend to oppose an externally utilized magnetic container. Contrasted with paramagnetism and ferromagnetism. answer
Certain substances especially some alloys of mercury , antimony etc. at very low temperatures of the order of -150 to -250 c show perfect dimagnetism and do not allow the magnetic fields to pass through . This phenomenon is called Meissner's effect and such substances are called superconductors.
