ULAANBAATAR, Jan 30 (Reuters) - A former Mongolian finance...

ULAANBAATAR, Jan 30 (Reuters) - A former Mongolian finance minister re-arrested earlier this month as part of an investigation into corruption claims surrounding the giant Oyu Tolgoi copper mine has been released on bail, a court official told Reuters on Wednesday.

Bayartsogt Sangajav, was first arrested last April and released in June. He was re-arrested on Jan. 16 and released late on Tuesday following a court order, said Bayarjargal Zagdaa, a spokeswoman for the district criminal court handling the case.

Authorities are investigating the 2009 negotiations over the development of the project, then owned by Canada's Ivanhoe Mines and now managed by Anglo-Australian miner Rio Tinto (RIO) RIO.L .

Bayartsogt was one of the signatories to the 2009 investment agreement that kickstarted Oyu Tolgoi's development. The deal granted a 34 percent stake to the Mongolian government and the remainder was held by Ivanhoe.

Ivanhoe is now known as Turquoise Hill Resources TRQ.TO , which is 51-percent controlled by Rio Tinto.

Turquoise Hill was not immediately available for comment when contacted by Reuters. Rio Tinto declined to comment.

Mongolia's prosecutor's office also declined to comment, a spokeswoman said.

The head of investigations at Mongolia's Independent Authority Against Corruption (IAAC) told a press briefing last week that it was investigating allegations that Bayartsogt owned shares in a foreign company, which went up in value after the 2009 agreement was signed. He didn't identify the foreign company.

The IAAC declined to comment on Wednesday.