The Oyu Tolgoi mine (Mongolian: Оюу Толгой, also Oyu Tolgoi, Turquoise Hill) is a combined open pit and underground mining project in Khanbogd sum within the south Gobi Desert, approximately 235 kilometres (146 mi) east of the Ömnögovi Province capital Dalanzadgad. The site was discovered in 2001 and is being developed as a joint venture between Turquoise Hill Resources (a majority owned subsidiary of Rio Tinto) with 66% ownership and the Government of Mongolia with 34%.