Upon entering, take the left path. It is guarded by the same groups of roekillik in the previous quest.
Once you reach the mine elevator room, take the north tunnel. Half way in is a group of two roekillik miners^ and a foreman^^. At the end of the tunnel is a room, guarded by an epicx2 greater rumbler. Behind and to the left of it is a small, antique cage. Grabbing it will summon a roekillik sandbagger, who snatches it away from you.
Return to the NPC you received your quest from for your reward.
Head to the lower level via the ramp at the north end of the first floor.
Locate the artifact - A small, antique cage - at ( -99, -39, -341 ) /waypoint -99, -39, -341. This location is right behind The Tundra Queen, a 56^^^ Epic (x2) tentacle terror mob accompanied by 4 56^ Epic(x2) tundra spawns. You cannot get to the cage without being in aggro range of the epics. Clicking the cage spawns a roekillik sandbagger, who stuns the group and makes off with the artifact. The quest will update for everyone in the group when one person clicks the cage.
Return to the NPC you received the quest from for your reward.
It used to be possible to drop down from the first floor to the basement via a well above the Forge, avoiding most of the mobs between the entrance and the clicky. The instance now has an uncrossable barrier around the well.