Orcs occupy Moria - After the Dwarves were driven from Moria by the Balrog, the mines were eventually taken over by Orcs.

"c. 2480  Orcs begin to make secret strongholds in the Misty Mountains so as to bar all the passes into Eriador.  Sauron begins to people Moria with his creatures." ~The Return of the King (Appendix B)