Pavo is initially found at the Left-Hand Mine outside Markarth. Unfortunately, the Forsworn massacred all the workers and chased off Pavo and his fellow miner Gat gro-Shargakh. Pavo shares his woeful story, and asks the Dragonborn to help.
Pavo is a Marriage candidate if the player is wearing the Amulet of Mara. Be advised that even after clearing out the Forsworn, they can respawn. This may result in Pavo's death.
Once Pavo returns to Kolskeggr Mine, he will offer to buy gold ore from the player for 50 per piece. His services may be of limited use, however (see bugs below).
If Pavo dies, the Dragonborn may receive a Letter of Inheritance from a Courier along with a sum of gold (minus the Jarl's tax).
Fulfilling the quest and letting the miners reclaim control of Kolskeggr Mine may not really help them. The Forsworn outside the mine will respawn the next time one visits and may kill the workers if they aren't saved.
Possible general game physics engine bug; when Pavo Attius leaves the miner's barracks at Left-Hand Mine after the Kolskeggr Mine has been cleared of Forsworn and he has paid the reward, he may rebound off the door and launch into the air, eventually crashing back to the ground and dying on impact.