Q1 2025 Performance Results

Key Highlights:

• President of Mongolia Khurelsukh Ukhnaa, accompanied by government officials and members of Parliament, were welcomed by Rio Tinto Chief Executive Jakob Stausholm, Oyu Tolgoi Chief Executive Deirdre Lingenfelder and other senior leaders to the Oyu Tolgoi underground mine on 20 March. During his visit, President U. Khurelsukh stated, “I take great pride in the 20,000 Mongolian people who are tirelessly working to transform the natural resources of Oyu Tolgoi into national wealth and prosperity. I also want to express my heartfelt gratitude to the foreign specialists who are sharing their expertise and working shoulder to shoulder with Mongolians.”
• Oyu Tolgoi has completed the construction of a new school for 1,200 students and a kindergarten for 200 children in the Gurvan Saikhan residential area of Dalanzadgad soum. The project was funded through the Gobi Oyu Development Support Fund (DSF). This complex directly meets local needs. The newly built School no.6 and Kindergarten no.33 were constructed with a total investment of MNT24.2 billion, making it one of the largest educational infrastructure developments.
• Rio Tinto in partnership with the University of Queensland in Australia, launched the first training of the South Gobi Underground Mass Mining Institute in SGUMMI offers a comprehensive, world class training program designed for both local and international mining professionals utilising the Oyu Tolgoi as practical training hub. In 2025, 28 participants enrolled in the program and are undergoing a year-long training program divided into four sessions. SGUMMI’s curriculum is based on international best practices and focuses on core engineering subjects, such as underground mining, geotechnics, mining engineering, and extraction management.

Environmental initiatives

• Oyu Tolgoi, for the fourth consecutive year, has been implementing the “Care Deeply” water awareness campaign. As part of this effort, individuals, researchers, and organizations actively taking valuable steps in water conservation, efficient use, protection, and restoration were recognized at the Blue Gold national forum held on March 21, 2025

Awardees of the Water Excellence Awards are:

• The Outstanding Organization: Durtmal Us LLC
• The Exemplary Citizen: Batdorj
• Excellence in Research: Chuluunbaatar

Their initiatives, research, and technological innovations are making a valuable contribution to the protection and sustainable use of water resources in Mongolia.

“Care Deeply” water campaign was initiated by Oyu Tolgoi in collaboration with the Water Agency (implementing agency of the Government), the Mongolian Association of Hydrogeology and Geoecology, the Galba-Uush Dolood Gobi River Basin Administration, and the School of Geology and Hydrogeology at the Mongolian University of Science and Technology. It aims to raise public awareness on responsible water use, recycling, and the importance of water, while also promoting the hydrogeologist profession and contributing to the training of skilled professionals.

Sustainable Development Initiatives in Umnugovi Province

• This year marks Gobi Oyu DSF’s 10^th year anniversary. Since its establishment in 2015, the Gobi Oyu DSF has invested MNT160 billion in the social and economic development of Umnugovi province, of this MNT46.3 billion was allocated to 169 education-related projects. Notable projects include:
• A 1,200-student school and a 200-child kindergarten in Dalanzadgad soum
• A 640-student school and a 200-child kindergarten in Khanbogd soum
• Kindergartens No. 25 and No. 26 (174-child capacity each) in Dalanzadgad
• The “Gobi Oyu – Student Scholarship” programme, which has supported 630 students with MNT1.5 billion.
• Full funding of the Umnugovi Natural History Museum, opened in May 2022
• To further strengthen education in the region, the DSF is launching a 2024–2028 programme focused on improving leadership and educational quality across Umnugovi’s schools.

For more information about the Gobi Oyu Development Support Fund (DSF), please visit the official website at www.goviinoyu.mn or follow the Facebook page: www.facebook.com/GobiOyuDSF.

Other

• Oyu Tolgoi has been partnering with national and local government agencies to enhance disaster preparedness and emergency response measures. As part of this commitment, Oyu Tolgoi has donated communication equipment worth MNT230 million to the National Emergency Management Agency (NEMA). Since 2020, Oyu Tolgoi has donated essential equipment and supplies worth MNT1.271 billion to NEMA to enhance emergency response measures.
• At Oyu Tolgoi, artificial intelligence and machine learning are now being used to predict current and potential future equipment failures before they occur.

Oyu Tolgoi is implementing the “Smart Copper Production” project, which aims to collect continuous data on vibration and operational parameters of equipment at the Concentrator Plant, Open Pit, and Underground Mine. By applying AI and machine learning, the system identifies faults and predicts potential failures in advance.

As of now, digital sensors have been installed on electric shovels, loaders, ball mills, semi-autogenous grinding mills, flotation tanks, the primary crusher, and conveyor belts. These sensors continuously collect data, enabling highly accurate analysis. This system allows for early maintenance planning, reducing downtime and costs, ensuring reliable operations, and ultimately increasing the efficiency of copper extraction in the long term.

Production Report

• Prioritising safety, we achieved our goal by maintaining an All-Injury Frequency Rate below 0.23 per 200,000 person-hours, with a recorded rate of 0.14.
• Globally, an average of 1.2 cubic metres of water is used to process one ton of ore. However, at Oyu Tolgoi, 0.23 cubic metres of water is used per ton of ore (in Q1 2025, 0.34 cubic metres of water used).
• 5% of the total workforce is Mongolian, and 23.2% of all employees are women.
• USD121 million has been paid in taxes, fees and other payments in the first quarter of 2025. Since 2010, Oyu Tolgoi has paid US$5.0 billion in taxes, fees and other payments, the VAT paid to Mongolian suppliers.
• As of the first quarter, we collaborated with 770 suppliers, 598 of which were local, spending 90% of our operational procurement on these national suppliers.
• Q1 2025 Performance Scorecard can be viewed here.

Production update

• On track for >50% increase in 2025 Copper production compared to 2024, with growth weighted to the second half of the year when concentrator conversion is fully commissioned and primary crusher 2 is complete.
• March was a record Copper production month: the underground mine continued to set material handling records achieving average of 28ktpd and record highs of 45ktpd.
• Strong performance from Open Pit operations with equipment availability improvements.
• Commissioning activities commenced for the new concentrator equipment during this quarter and are forecast to be progressively completed through to the second quarter of 2025.
• Construction of primary crusher 2 is progressing to plan and remains on track to be completed by the end of 2025.
• The ramp-up remains on track to reach 500 thousand tonnes of copper per year (100% basis and stated as recoverable metal) for the underground and open pit mines for the years 2028 to 2036.