1 - 55
You could level to 75 by Mining only Ghost Iron, but you will gain skill points a lot less frequently after around 55, so I recommend switching to Townlong Steppes or Dread Wastes to mine some Kyparite Ore. It's is a higher level ore, and you will get a skill point every time.
Valley of the Four Winds
Valley of the Four Winds is the best place to level Mining, but it's often farmed by a lot of players.
Jade Forest is also a great place to farm.
55 - 75
You should reach 75 just by doing one lap in each of these zones.