Oyu Tolgoi Boxcut and Decline Project

South Gobi Desert
Oyu Tolgoi LLC
  • Copper
  • Gold
Contract type
Schedule of rates
July 2016 - ongoing

Thiess, in joint venture with local contractor Khishig Arvin, will deliver the first underground decline project at the Oyu Tolgoi copper and gold project in Mongolia's South Gobi Desert.


As part of the large-scale expansion of Oyu Tolgoi, Thiess and Khishig Arvin will deliver the boxcut and decline project from August 2016. The boxcut will provide a safe and secure entrance for the underground tunnels and conveyors expanding over 10 kilometres and depths of up to 1300 metres. The twin declines provide up to 395 metres of vertical lift with a maximum gradient of 18 per cent. The conveyor to surface declines consist of 16.6 kilometres of tunnels and 35,000 cubic metres of large excavations to house the required conveyor transfer and drive stations.

For the duration of the project, Thiess is focused on building local capability, with over 90 per cent of the workforce being Mongolian.

Oyu Tolgoi is jointly owned by the Government of Mongolia (34 per cent) and Turquoise Resources (66 per cent, of which Rio Tinto owns 51 per cent). Rio Tinto has managed the Oyu Tolgoi project since 2010.   

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