Welcome to the forum! :)
It sounds like the minis either don't like people (timid, unconfident, or afraid), or they think people are useless and could care less. In either case, I would spend 30 minutes of undemanding time with them for 7 days in a row. Go in and sit with them and then wait. If they come up to you, great, but DON'T touch them. Let them be the first ones to make contact. If you can pick out the ones who are the most unconfident or uninterested, if they have stalls, maybe do the 30 minutes in the stall with them, that way they don't have too much distraction. You will be surprised how this will change their perception of you, and hopefully people in general.
When you do interact with them, make every moment count. Do LOTS of friendly things, like give them treats, scratches, take them out to graze for awhile. When you lead them, puts lots of slack in the line. Believe it or not, if you lead a horse tightly or shortly, that affects how they precieve you (in a negative way). It would be great if more then one person would spend the 30 minutes of undemanding time with them, that way it helps them get confident or interested in all people.
This is all about changing perceptions. The more friendly things you can do, the more natural you can be with them, the more they will want to be around you.