BHP Billiton Ltd. (BHP) is in the process of closing down its exploration office in Mongolia, a company spokeswoman confirmed Thursday.

The diversified miner opened an office in the central Asian country in 2005, having signed exploration agreements with a number of Western companies in the region.

BHP has previously expressed an interest for the Tavan Tolgoi thermal coal mine, alongside Shenhua Energy Co., Vale and Peabody Energy Corp. (BTU), according to people familiar with the situation.

BHP didn't say why it was closing the office.

Resources companies have been awaiting a solid investment framework for years to mine Mongolia's copper, gold, coal and uranium riches.

But progress in government talks with Ivanhoe Mines Ltd. (IVN) for a blueprint deal on Oyu Tolgoi, a US$3 billion copper-gold project, has been piecemeal.

-By Elisabeth Behrmann, Dow Jones Newswires;

61-2-8272-4689 elisabeth.behrmann@dowjones.com