Hmm... I have a few ideas about mining. Maybe by rooting through the dirt with a shovel and pick you could acquire some of the weaker materials, such as bronze, copper, iron, etc. Maybe in some distant corner of the world you could mine and find mythril (a VERY distant corner in the world, and like in the Mines of Moria in Tolkien, it can easily be dangerous)
Also, perhaps you could go adventuring and find yourself battling something like an Adamantite Rock Golem, or something. You could hack it to pieces and salvage the Adamantite and stick it in your blade. Hey, maybe your mining skills could give you an advantage in this kind of fight
You should have to search or do some other annoying task in order to find rare ores. And to get the simpler ones you just have to hike to the mines and maybe defend yourself against any oncoming monsters until you get a full load, or until there\'s no more ores. Then you would just wait until it re-spawned.