There are two different ways that you can use to level your mining to 450 in Wrath of the Lich King. They are smelting and mining node spawns. You can not smelt to 450 alone but you also can not level to 450 mining nodes efficiently either.
It is best to mix these two methods of leveling together to get to 450 the fastest. You will be able to get your mining to 450 in less than a day using an efficient mixture of both smelting and mining nodes in the world.
A lot of people ask me, "How can I smelt if I do not mine the ore first?"
Obviously, that's kind of an easy question that most people over look. You can get all of the ore you need off the Auction House. The best part about buying ore off the auction house for smelting is that it's cheap because other players do not know you can smelt your mining most of the way to 450 so they go out and mine the nodes for us and then they have nothing to do with the ore but sell it to us at a cheap price.
Using Smelting to Level Your Mining
If you have a lot of gold you will be surprised at how much you can actually smelt up through 450. Some of the ore that's rare like silver ore can be used to almost go uninterrupted in smelting all the way to 375 with very few exceptions.
If you're willing to buy rare ore to smelt you can go 1-290 without ever leaving the auction house. At which point you'll have to go out and mine some nodes for 10 levels. Then you can go from 300-315 smelting and you'll have to mine 10 more levels. Then you can go from 325-340 where you have to mine 10 more levels again. And the final step for smelting you can go from 350-375.
Let's recap that, you can smelt the following ranges:
That means that if you have enough gold you only have to mine nodes for 105 skill ups out of 450. Pretty cool right?
Now, most of you probably do not have a lot of gold to be spending on rare ore so you will have to go ahead and mine through more than the stages listed above, but at least half of the 450 skills can be done without the use of rare ore and it's cheap.