The following answers are for educational use only.
The fastest mining experience is 'Speed Mining' The Process of mining it then dropping it. The Best ore to use is preferable iron.
However complicated and controversial, is to use a bot which i don't recommend. All "can" get you banned. There are 1 or 2 elite bots out there though, that does the job very well. Which i will not list.
-CrashShock/Cad Former Rs Member and Cheater