Tested your theory, just for the hell of it, but only partially.
Farmed ore in Uldum for 1 hour exactly.
Fighting off mining bots, and only on a level 84 Huntress with a 280 speed mount, managed 16 stacks of elementium, 2 stacks of the other ore, name eludes me as i am at work. This is a farming toon in a level 25 guild, so i get the speed and farming buffs.
Elementium ore goes for 90 gold per stack. Did not sell any of my motes tho, and i am collecting them. Engineering helps for the motes.
Managed to make almost 1600 gold for that hour.
Will try again soon and go for the full 3.2 hours. Levelling the huntress just on mining.