Trial of the Crusade 4

Designations
You'll need two tanks, one for Anub'arak and one for the Nerubian Burrowers.
Assign one ranged DPS or one Death Knight to destroy the Frost Spheres floating above the raid for the duration of the encounter.
Phase 1: Tank-and-Spank
Your designated Sphere Breaker should take down at least 3 Frost Spheres during Phase One. These will create patches of Permafrost which will stop the Nerubian Burrowers from burrowing before the raid can kill them.
The main tank should tank Anub'arak near one of these patches. The off-tank should take the Nerubian Burrowers to the same patch used for Anub'arak.10-man encounters only see one Nerubian Burrower spawn every few seconds, so DPS should focus fire on every second Nerubian Burrower that spawns and then switch to area-of-effect skills to damage the Burrower and Anub'arak.
Anub'arak is a pushover to tank, dealing basic damage and stunning the tank every now and then. He also casts a damage-over-time spell on a few raiders, but it's nothing that can't be outhealed.
Nerubian Burrowers attack at a faster rate when they are near each other. One off-tank is often enough if the DPS can quickly kill those Burrowers.
If you have Deadly Boss Mods, the assigned Sphere Breaker should get to work 20 seconds before Anub'arak burrows.
And Anub'arak will burrow. No puny patch of ice will stop him.