Managed to get this turkey cooked with 5 shamans after alot of !@#!$... what I did... drop 5 earth elementals to help control the adds, burn down the big elite rock guy asap, and make sure you can move your whole group by strafing left and right quickly to avoid the ice spikes that will appear below you before you get tossed into the air. Just keep fighting the adds until he goes underground, at which point you can unload on him. The key seems to be making sure to move away from the spikes.