The Negative Energy Mines
Whatever cataclysm that befell Arkenreln in the times before had grave consequences on the land around it. Negative magical energy, a potent ingredient in anti-magic amulets, armour and potions can be found in vast quantities beneath the ruins and ancient crypts of the realm. The largest well of negative energy sits beneath a vast ruin system near Norge. It is dangerous, dirty work to refine and contain this magical energy, but it is the source of most of Arkenrelns wealth.
The mines are extensive, with pully systems and mechanical ventilation allowing workers to reach depths that would have been impossible otherwise. Miners occasionally break into old ruins or tombs, leading them to employ groups of mercenaries and mages to delve into newly discovered ruins and clear out the abominations that shuffle through the long dead halls.