Thiess secures two five-year mining contracts in Mongolia

Thiess, a global leader in contract mining, has secured two significant five-year contracts in Mongolia, encompassing underground services at Rio Tinto's Oyu Tolgoi copper-gold mine and Coal Handling and Preparation Plant asset management for Energy Resources' Ukhaa Khudag coal mine. These agreements solidify Thiess's long-standing presence in the crucial Mongolian mining sector, particularly highlighting its expanded role in Oyu Tolgoi's complex underground operations which will become its largest worldwide, and underscore its expertise across diverse commodities and operational challenges.

October 23, 2026 – Thiess, a prominent international mining services provider, has announced the successful award of two five-year contracts in Mongolia, reinforcing its strategic footprint in one of Asia’s most vital mining jurisdictions. These agreements represent a significant commitment across both underground and surface operations, covering the world-class Oyu Tolgoi copper-gold mine managed by Rio Tinto and the Ukhaa Khudag coal mine operated by Energy Resources.

The dual contract wins underscore Thiess’s robust operational capabilities and its proven track record in delivering specialized mining and asset management services within complex environments. The agreements, effective as of the announcement date, are poised to expand Thiess’s operational scale in Mongolia, contributing to both the country's resource development and the company's global growth trajectory.

Thiess Bolsters Presence at Oyu Tolgoi, World-Class Copper-Gold Operation

At the forefront of these new agreements is the extension and expansion of Thiess’s involvement at the Oyu Tolgoi mine, a globally significant copper-gold project located in the South Gobi region of Mongolia. For this critical underground contract, Thiess will operate via its established Thiess-Khishig Arvin joint venture (TKAJV), a partnership that has maintained a consistent presence at the Oyu Tolgoi site since 2016.

The scope of work under the Oyu Tolgoi contract is extensive and technically demanding, focusing on core underground mining activities essential for the ongoing development and production ramp-up of the mine’s massive underground block cave. Key responsibilities include:

Underground Development: Driving new tunnels and access ways crucial for both material handling and operational logistics within the vast subsurface network.
Ground Support Installation: Implementing advanced geotechnical measures to ensure the stability and safety of underground excavations, a paramount concern in deep mining operations.
Construction of Block Cave Infrastructure: Building the foundational elements required for the successful execution of block caving, an innovative bulk mining method that relies on controlled rock mass collapse. This infrastructure is vital for ore extraction, ventilation, and personnel movement.

The Oyu Tolgoi underground mine is one of the most ambitious and complex mining projects globally, characterized by its deep excavations and the inherent challenges of large-scale block caving. Thiess’s continued and expanded role signals a deep trust from Rio Tinto in TKAJV’s specialized expertise to navigate these intricate technical and operational hurdles. The scale of this engagement is particularly noteworthy for Thiess, as the headcount for this operation is expected to rise significantly. The contract is anticipated to generate more than 110 new positions in the coming months, with the total workforce projected to grow to nearly 800 employees by the end of the five-year contract period. This expansion will solidify Oyu Tolgoi as Thiess’s biggest underground mining operation worldwide, underscoring its pivotal role in the company’s global portfolio and its leadership in specialized underground services.

Optimizing Coal Operations at Ukhaa Khudag

In a separate, equally strategic agreement, Thiess will deploy its expertise in asset management to the Ukhaa Khudag mine, a key coal operation in Mongolia’s prolific Tavan Tolgoi basin, operated by Energy Resources. This contract focuses on providing comprehensive Coal Handling and Preparation Plant (CHPP) asset management services.

Coal Handling and Preparation Plants are indispensable components of modern coal mining, designed to process run-of-mine (ROM) coal to meet specific market specifications for quality, size, and moisture content. Efficient CHPP operations are critical for maximizing product value, minimizing waste, and ensuring consistent supply to end-users, particularly in export-oriented markets like those served by Mongolian coal producers targeting China.

Thiess’s responsibilities at Ukhaa Khudag will encompass a broad spectrum of services aimed at enhancing the CHPP’s operational performance and longevity:

Asset Management: Implementing strategies for the optimal utilization, maintenance, and replacement of plant equipment to ensure peak performance and reliability.
Technical Support: Providing specialized engineering and operational guidance to address complex technical challenges and optimize processing parameters.
Supply Chain Management: Streamlining the procurement and management of spare parts, consumables, and other essential supplies to minimize downtime and control costs.
Planning: Developing detailed operational and maintenance schedules to promote efficient plant operations, including preventative maintenance programs and production scheduling.

By entrusting these critical functions to Thiess, Energy Resources aims to leverage the contractor's extensive experience in maintaining high-value processing infrastructure. This partnership is expected to lead to enhanced operational efficiency, reduced operational costs, and improved product quality at the Ukhaa Khudag mine, reinforcing its competitive position in the global coking and thermal coal markets.

Strategic Significance for Thiess and Mongolia

These two contracts are a testament to Thiess's enduring commitment to and success within the Mongolian mining landscape. The company first entered the Mongolian market in 2007 and, over nearly two decades, has built a reputation for providing robust mining and maintenance services across multiple projects in the country. This long-term engagement reflects Thiess's strategy of establishing deep relationships with clients and understanding the unique operational and logistical challenges of the regions in which it operates.

Michael Wright, Thiess's executive chair and CEO, articulated the strategic importance of these awards. "These awards demonstrate the trust our clients place in Thiess and reflect the strength of our long-standing partnerships with Oyu Tolgoi and Energy Resources, as well as the capability of our team," Wright stated. He emphasized the core tenets of Thiess’s operational philosophy, adding, "Our success is built on our global expertise, our local people and our local capability, and we’re proud these contracts will create new career opportunities as our workforce grows." This statement highlights Thiess's dual focus on leveraging international best practices while fostering local talent and economic development, a critical factor for sustainable operations in emerging mining regions.

The Mongolian contracts also follow a period of significant growth for Thiess. In June 2025, the company announced a substantial contract extension valued at A$2.3 billion (approximately $1.5 billion USD) over three years at Jellinbah Group’s Lake Vermont mine in Queensland’s Bowen Basin. This recent series of major contract wins underscores Thiess’s strong market position and its ability to secure large-scale, long-term engagements across diverse commodities and geographical regions, signaling robust growth for the global mining services provider.

Broader Implications for the Mining Sector

For the broader mining industry, these contracts hold several important implications. Firstly, they reaffirm Mongolia's status as a strategically important jurisdiction for global resource development, particularly for copper, gold, and coal. Despite past regulatory and investment uncertainties, the continued commitment by major players like Rio Tinto and the expansion of key service providers like Thiess signal a maturing and increasingly stable operational environment.

Secondly, the nature of these contracts highlights the increasing reliance of major mining houses on specialized contract miners for complex operations. The expertise required for advanced underground block caving at Oyu Tolgoi and sophisticated CHPP asset management at Ukhaa Khudag necessitates highly skilled workforces and specialized equipment, capabilities that companies like Thiess are uniquely positioned to provide. This trend allows asset owners to focus on core strategic objectives while outsourcing operational intricacies to proven experts.

Finally, the significant job creation outlined for the Oyu Tolgoi contract, with headcount rising to nearly 800 employees, demonstrates the substantial economic benefits that accrue to host nations from these major mining investments. The development of a highly skilled local workforce in areas such as underground mining and complex asset management will have long-lasting positive impacts on Mongolia's industrial capacity and human capital development.

Future Outlook and Operational Impact

Looking ahead, these five-year contracts promise a period of sustained activity and growth for Thiess in Mongolia. For the Oyu Tolgoi project, Thiess’s expanded underground services are crucial for the continued ramp-up of the block cave, which is central to the mine's long-term production profile and its position as one of the world’s largest copper-gold producers. Reliable underground development and infrastructure construction are foundational to achieving planned production targets and cost efficiencies.

At Ukhaa Khudag, Thiess’s CHPP asset management expertise is expected to enhance operational uptime, reduce maintenance costs, and ensure consistent coal quality, which are vital for maintaining Energy Resources’ competitiveness in a volatile global coal market. The focus on planning and technical support implies a proactive approach to operational excellence, contributing to the mine’s overall sustainability.

For Thiess itself, securing these significant contracts solidifies its global leadership in contract mining, particularly in complex underground operations and advanced asset management. The Oyu Tolgoi contract, becoming its largest underground operation, will undoubtedly enhance its reputation and capabilities in this specialized field. These awards, alongside other recent successes, position Thiess for continued strong performance and demonstrate its ability to forge and maintain long-term, high-value partnerships across the international mining landscape.