This is an extremely easy way to make a TON of gold based on your server economy/professions.
It's quite simple, almost everyone has forgotten about the Isle of Quel'danas. They've also forgotten about the MASSIVE amounts of Adamantite Ore on this island (you get to the island from the portal in Shattrath).
The map:
The blue route is easy and effective at 80, at level 73 i got minimal agro from the mobs on the island and there was only 1 other player from my faction on the island. A single loop takes about 7-9 minutes with 6 respawns total, Khorium and Rich Adamantite also spawn. One loop usually yields about 15 up to 20 ore. Prices on ore usually go for 40g/stack and around 100g/stack of bars. I've gotten up to 400g/hour in this spot.
Hint: If you need to level mining quickly, try the Netherwing daily quest island.
Happy farming O.O