Just wanted to fill out my spell book so did this quest today. As you can buy the gold bar in POK (and other places) and at level 50 (60) you can charm a miner (dire charm) so it is an easy quest that is safe. I used my war merc and the dire charmed miner (any that are green in zone at level 60 are DC ready) to clear out about 20 miners before I got the two gleaming ores.
The only problem with the spell is the spell gem stays grayed out for about 5 minutes once you mem it .....
Spell casting reinforcement AA did not seem to have any effect to lenghten the duration past one minute.
But 500 mana for 5 mana cast is nice and at level 60 with KEI this spell give you a total of about 100 mana a tic. (50 + 50) about
Fell / Dadijob