Where are the best places to mine some ore?
Well there are scattered ore veins all over the wilderness, but for concentrated mining, mines are best. Most mines seem to specialize in one type of ore. I know of a handful of mines off the top of my head, but since my previous character was a mage, I never made extensive note of where mines for each type of ore are. If you don't mind wiki'ing I'm sure either of the two popular TES wikis can tell you, but I prefer to find things on my own.
