Gotta absolutely love Wichuras maps. Including it in the faction base system is something awesome just to think about. Should also be a lot easier to implement, considering it would be technicaly just another base.
In my opinion:
Of course resources shall not be depletable; that was stupid back then and will it be stupid right now. Of course, they should be spread to larger areas (deposit having less than in public mines) and regenerate a lot more slowely. Random quantity on purchase (100-200 random type resources, 1:10 spawning hq deposit) would kick ass.
Picking a location for the base is pretty strangled as it is, should not be with mines (draging a guy somewhere and telling him to make you an abandoned mine there?) though it should be at least semi-aviable, e.g. picking a general location for the mine (around what city?) - as it was, i believe, intended before.
Price suggestion (on todays economy) is 30k. Of course, subjectible to inflation (like in cars case).