What is Drums of Forgotten Kings?

[Phanes]

http://huntsmanslodge.com/3575/leath...ers-rejoic.htm

Here it says they are a 30 minute buff.

So it appears they will have 50 charges and they will be a 30 minute buff.

So for most heroics cast them right before the first boss mob and they should last you through a run unless you wipe.