Leveling up certain skills has been a pain for some time now, and while some skills have received leveling changes, mining has been left behind. As things stand currently, if you don't run around in circles just looking for ores every 10 or 20 levels or so, you could easily find yourself having to do a massive amount of catch up once your character reaches the level cap. The amount of mining you do in the normal course of leveling just isn't enough to keep up with your experience gain.
Drysc says that Blizzard has finally noticed that this "isn't fun" and plans to do something about it in patch 2.4. The various types of ore will be adjusted so that you can consistently level up your skill from the nodes available in the zones where your character will be leveling, without you having to go back and spend lots of extra time in areas where you don't have any quests.