No you can use them anywhere. I use the one in Hillsbrad in the Hillsbard Foothills and I am Horde, have to kill my way in there but eh. All you have to do is have the ore after minning it and them click on smelting in the abilities menu and then click on the bar you want to make but you have to have that type of ore. Like bronze takes a bar of copper and tin. It will list the number of them you can make next to the item you want to make and then you just click on create or create all and let it go. Don't move either it will stop it.