I'm actually surprised anyone would ask this question - at least at this level of mining.
Goto Hellfire, goto your main towns miner trainer, you were there at least once to get skill cap to 375, and learn to smelt all the ores that you haven't yet.
Although you can get your skill to a level where you can mine higher and higher ores you still needed to go back to the miner trainer to learn to smelt the ore.
At mining 375, you will learn to smelt Khorium. <Thumbs up> Congratulations.