Project data
Overview
Thiess, through the Thiess–Khishig Arvin Joint Venture (TKAJV), has a long and established history at the Oyu Tolgoi copper and gold project in Mongolia’s South Gobi region. Since first commencing work in Mongolia in 2007, Thiess has delivered numerous major underground and surface construction programs at OT, including significant decline and boxcut development.
Thiess is focused on building local capability, with over 90 per cent of the workforce being Mongolian.
In 2016, TKAJV began delivering the Oyu Tolgoi Boxcut and Decline project, successfully constructing 6.5 kilometres of twin declines and supporting underground expansion with safe and innovative engineering solutions. This work laid the foundation for a series of additional underground development packages and marked Thiess’ return to large‑scale underground mining services in Mongolia.
In 2022, the joint venture secured a contract extension to continue underground development works at OT, including construction of a 6.4‑kilometre concrete conveyor decline road, conveyor hanger and change house, and installation of conveyor hanger bolts. These works followed the safe completion of the conveyor line decline tunnel connecting key underground infrastructure
In 2024, TKAJV was awarded a significant three‑year mining services contract to deliver underground ground support and development work at Oyu Tolgoi, utilising more than 300 Thiess people. This contract marks TKAJV’s formal return to underground mining services, building on recent underground construction successes and further cementing the JV’s position as a trusted partner at one of the world’s premier copper operations. The project provides new opportunities for the JV to expand its scope and continue delivering safe, efficient and high‑quality mining services.
Thiess’ commitment to Mongolia is reflected in its strong focus on local employment and capability development. More than 90 per cent of the TKAJV workforce is Mongolian, supported through structured training, skills development, and community investment programs. The JV continues to deliver community programs in health, education and social development, reinforcing long‑standing partnerships in the region.
With a proven track record of safe and innovative underground delivery, Thiess and Khishig Arvin remain key contributors to the future growth of Oyu Tolgoi and Mongolia’s mining sector.
