Iron, Silver and Gold so far atleast allow skillups in green until you unlock the ability to mine the next metal. However Iron and mithril you get no opportunity to level through smelting at all. I'm not sure if originally Blizzard just didn't get it right from the start. Or maybe it possible Elysium has it coded it wrong. But it is making the process of leveling mining so much harder than it should be.
I struggled through iron by just mining it in the field and I thought my struggles were over when Gold was working. Then I got to 175 mining and gathered some mithril ore. I was very disappointed to see that smelting mithril bars was gray immediately. I know that Blizzard made some adjustments to mining levels to make it easier. I'm not asking for that. But I believe the smelting levels should at least be green until you gain access to mine the next metal.