Oyu Tolgoi mine in Mongolia's South Gobi region (Photo: Reuters)

Ulaanbaatar (People's Daily) - On Tuesday, Mongolian authorities detained two of the country’s former prime ministers for their involvement in the development of a giant copper-gold mine.

Former Prime Minister Bayar Sanj signed the original mine deal in 2009. And in 2015, former Prime Minister Saikhanbileg Chimed sealed the mine’s expansion agreement. Authorities cited corruption and abuse of power when taking the former leaders into custody.

An investigation into the first agreement to develop the Oyu Tolgoi mine with Canadian investors that later saw the mine expanding is still underway. 

The 2009 agreement gave Ivanhoe Mines a 66 percent share of the Oyu Tolgoi, with the Mongolian government holding the remainder. Ivanhoe changed its name to Turquoise Hill Resources in 2012 after Rio Tinto became its majority stakeholder.

Authorities have already arrested former finance minister Bayartsogt Sangajav, one of three government ministers to sign the 2009 deal.