Trollgore will instant cast consume every 15 seconds. This ability can be line of sighted.
Pull Trollgore down the stairs and into the tunnel entering into his room. Place a dps class at the top of the stairs where he is pulled from and assign them to stopping and killing adds before they reach Trollgore. This is because every nearby unit, either player or enemy adds to his consume if hit.
Every 10-12 seconds, run out of line of sight until he has cast consume, then run back out and dps him. You can see when he has cast consume because his consume buff stack will increase (If done properly it should only increase by 1 each time).
The strategy of this fight is very similar to the Firemaw strategy. The healer can be positioned so that they are always in Line of Sight of the tank, but not Trollgore. If done using this method, you should have plenty of time before Trollgore reaches 10 stacks.
Additional Note Edit
It is useful for everybody to synchronize stopwatches as the boss is pulled, keeping an eye on when he will cast consume. Ventrilo or Teamspeak is also useful for this, as you can have one person announcing when to move out.
Pets, mirror images, treants etc. do not add consume stacks in this fight.
An overgeared group can simply dps down Trollgore before consume reaches ten stacks, removing any difficulty of this achievement.
See also Edit