I've never understood why people who have mining smelt their ore into bars and sell it as pure ore. The reason is, if you plan on making gold, you should always turn the ore into bars because bars, at least on my server, are always more expensive than ore. For example, a stack of copper ore on my ah goes for about 2g tops. But bars sell from 7 to 9 gold a stack. That's copper alone. So higher ores are the same way, selling for 30g a stack for ore and even as much as 70g a stack.
So, if the purpose is to make money with mining, why sell it as ore when you can make more money with bars since mining automatically gives you the ability to smelt your ore into bars?