So, you want some extra gold as a miner?
Well, I've found a pretty easy and fast way, by mass producing and selling one item:
Eternal Belt Buckles
Eternal Belt Buckle - Item - World of Warcraft
The materials
4x - Saronite Bar
1x - Eternal Earth
1x - Eternal Water
1x - Eternal Shadow
The good part
There is always, and I mean ALWAYS a high demand for these items. And as you have probably noticed, these are extremely cheap to make if you are a miner. Seeing how you will probably have a ton of Eternal Earth/Shadow on top of that Saronite Ore, all you will have to buy (Or get out of Cobalt Veins), is the Eternal Water.
So far this has been working perfectly fine for me, and I have been making atleast 500g an hour off of these lovely items.
I hope you've enjoyed reading it, and good luck mass producing them buckles!