Welcome back! Which mining ship do you want? And I can direct you to the station, BAF| is currently the most active military faction Kruger is the most active trading faction. Otherwise have fun! etc etc
Mining ships are all over the place, Pittsburgh in New York sells Hegemons, if that's what you're looking for/are in the vicinity of Liberty. Just make sure you read up on the Mining Guide if you haven't already, since that should cover most your questions on mining.