Depending on the path your character takes throughout the rest of the game, it's easy enough to clear everything up to the barrier in the center of the Spiral Pit, report that to Commander Lynn, then get the second quest from the job board in Silvar to go back and get past the barrier and clear the rest of the Pit. When I've played, I generally don't have high enough Dispel Barrier to get to the center until later, so the routing makes sense. But the game is non-linear, anyway.