[Annunfuiniel]

Glad that you agree, Dain (you might still wanna check the spelling of my name, though [img]smilies/biggrin.gif[/img] [img]smilies/wink.gif[/img] ). I agree with you on that drum part, I see them also as the drums of the orcs and not the sound made by the balrog.
To your question: yes, I would think that the upper reaches of Moria were deserted when Balin arrived there. It seems that at first they had to defend themselves against a threat that came from the outside, from east.
I have the feelin' that the orcs were pretty much as scared of the balrog as any other creatures on earth so I really don't see them lodging with it in the dark ditches.