The game manual states: "Gold. Earned by killing opponents as well as from gold mines your team
has captured."

It says nothing about earning gold from killing mobs.  However I have seen people state you do get gold for killing the mobs.  I do not think this is necessarily true.

For example: Torchbearer casts rain of fire and ice on a stack of 20 mobs.  Gold should jump up big time for killing all those guys at once.  However there is no gold earned at all from this.

Or do you not get gold for using special abilities against mobs?  Do only normal weapon attacks gain you gold?

Thanks for clearing this up.