In the South Gobi desert , water is the most precious natural resource. To ensure ongoing availability of surface water, Oyu Tolgoi is committed to using water carefully, balancing the mine’s operational needs while ensuring water is fully available for local residents and future generations.
Oyu Tolgoi operates some of the best water conservation standards worldwide, using less than half the global average of water per tonne of ore processed for similar mines. This means all of the water at Oyu Tolgoi is used and reused until it is lost through evaporation. This has been achieved through a number of measures:
- High-effciency tailings reclaim;
- 100% cooling water reuse;
- 100% mine water recovery and reuse;
- 100% treated domestic waste water reuse;
- 100% truck wash water reuse;
- Measures to prevent evaporation;
- Ongoing water conservation measures; and
- A zero direct discharge policy, meaning that no waste water will be directly released into the environment.
Given the dry nature of the South Gobi region, coupled with the requirements of an operational mine and growing population, Oyu Tolgoi has undertaken detailed hydrogeological investigations in the region since 2003. Through these programs Oyu Tolgoi has identified two large aquifers, geological formations containing underground water, which are at least 150 metres below the surface - far deeper than the surface water sources used by local people and animals.
Detailed hydrogeological investigations of the Gunii Hooloi aquifer have concluded that it has water reserves of 6,800,000,000 cubic metres. Under Oyu Tolgoi’s water permits, the mine can only use less than 20% of the aquifer over 40 years, ensuring that the majority of the water remains underground for future generations.
Oyu Tolgoi’s reserves have also been identified by hydrogeological surveys and water exploration efforts. With proper water management at Oyu Tolgoi, sufficient water resources will be available for the needs of both the mine and local communities. Oyu Tolgoi operates a comprehensive water monitoring program that incorporates hydrogeological modeling and prediction of water drawdown of the Gunii Hooloi aquifer.
Since 2014, Oyu Tolgoi has consistently achieved annual water recycling rates above the mine’s targeted recycling rate of 80%. Oyu Tolgoi has been designed as one of the most water-efficient mines in the world with average water use of 0.37 cubic metres of water per tonne of ore processed in 2020. The water used by Oyu Tolgoi comes from a deep and saline aquifer and has no impact on drinkable water in the region. In 2020, water used by Oyu Tolgoi has been continuously recycled at an average rate of 87.7%. An independent water audit is undertaken every five years, with the last audit completed in 2016. Compliance with water management and conservation policies, standards and legislation in 2020 was ensured through diverse processes including inspections from the Government of Mongolia as well as local community field verifications.
During the course of 2020, Oyu Tolgoi successfully sealed and rehabilitated 32 exploration water bores. These areas were handed over to the local government in cooperation with local communities. In addition to the above and as part of the Water Communication Plan, Oyu Tolgoi LLC undertook various activities in 2020, including:
• two clean-up initiatives for local water sources; and;
• creation of a short video outlining the value of water published on social media to provide information on water usage and standards.