The company, which is 66% owned by Canada-based Ivanhoe Mines Ltd and 34% owned by the Mongolian government, said: "No injuries have been reported and all staff have been accounted for. The fire is out, and the damage was confined to the roof of the building."
The emulsion plant is where explosives are prepared for the open pit mine.
Oyu Tolgoi is due to begin first commercial production by mid-2013. Anglo-Australian miner Rio Tinto PLC is the project operator and owns a 49% stake in Ivanhoe Mines.
By Alex MacDonald
Copyright (c) 2012 Dow Jones & Company, Inc.