The vast majority (approx. 90%) of the water used by the Mitsubishi Materials Group is seawater. However, since shortages of freshwater including industrial water and groundwater could affect our business operations, we have included “Effectively Use and Conserve Water Resources” in our Environment Policy. We are working to reduce water usage through initiatives such as reuse and recycling.

In addition, we manage water-related risks arising from disasters such as typhoons and flooding, which have become increasingly frequent in recent years. We implement measures for reducing water risks at each site. To reduce our use of freshwater resources, we take actions such as the effective use of seawater, water conservation through more efficient production processes, the introduction of water-saving equipment, water recycling, and the thorough purification of wastewater. As measures against flooding, we take initiatives including the elevation of buildings, pumps, and electrical equipment, the installation of drainage pumps, as well as the implementation of disaster drills assuming high-water events. We also take measures to prevent abnormalities in the quality of the effluent from our facilities and to prevent water quality accidents. These measures include the management of effluent under our own standards that are stricter than laws and regulations, as well as the introduction of sensors that detect abnormal water quality and a system that stops water discharges automatically.

To ascertain the state of water risks at the Group’s manufacturing facilities (some of which include research institutes), we are utilizing the Aqueduct water risk assessment tool developed by the World Resources Institute (WRI) to conduct individual risk assessments for each facility, covering various water risks including those relating to securing water resources and those of incurring flood damage.
There were 11 Group company locations rated as having high water stress, but sales related to these locations accounted for 0.7% of Group company sales. In the fiscal year ended March 2026, water withdrawal was 317 thousand m³ and water consumption was 70 thousand m³★. Additionally, in order to ensure that water risk assessments are in line with actual conditions at these facilities, we supplement the results of water risk assessments performed using Aqueduct by taking into account information including the history of any past water risks that have materialized at each facility (history of occurrences of flood, drought, and water supply quality deterioration, etc.) and water usage associated with business activities (amount of fresh water and groundwater used, emissions of pollutants contained in wastewater).
The results of these supplemented water risk assessments are used to produce visual representations of water risks for each facility, using radar charts displaying risk scores for each assessment item, and shared with each business location. Each business site registers items assessed as high risk as risk factors unique to that facility, and engages in risk management by formulating and implementing measures including the reduction of water risks.

"Water quality risks" are assessed separately for both water supply and wastewater, from the viewpoints of impact on operations due to the deterioration of water supply quality and impact on the environment due to wastewater at business sites. "Regulatory and reputation risks" are also assessed for both water supply and wastewater, from the perspectives of the strictness of water supply and wastewater regulations and local reputation.

Our company is engaged in copper mining operations in Chile, a region with a high risk of water stress. To ensure a stable supply of the significant volumes of water required for operations, we are working to maximize water-use efficiency and reduce new water withdrawals. In collaboration with joint venture partners, we strive to coexist with local communities and maintain long-term business continuity by minimizing freshwater consumption, promoting water reuse, and mitigating environmental impacts.

The Mantoverde Mine sources all the water required for its operations from desalinated seawater. In 2025, seawater withdrawal amounted to 20.5 million m³, an increase of 41% from 14.6 million m³ in 2024. Water-use intensity increased by 36% from 2024 to 0.697 m³ per tons of ore processed. This increase was attributable to higher water demand associated with the ramp-up of sulphide ore processing and copper concentrate production. The Mantoverde Development Project achieved commercial production in September 2024, and its sulphide concentrator ramped up to full nominal throughput by the end of that year. 
In 2025, 11.1 million m³ of brine generated through the seawater desalination process was returned to the ocean as managed discharge. The discharge complied with Chile’s Norma de Emisión DS 90, which regulates the discharge of liquid waste into marine and inland surface waters.
The desalination plant has also introduced an ocean monitoring and early-warning system. By enabling the plant to identify and respond proactively to risks associated with changing oceanographic conditions, the system supports a stable supply of desalinated water and improved operational continuity

The Los Pelambres Mine is working to increase its use of seawater and maintain a high water recirculation rate. Its desalination plant commenced operations in 2024 and currently has a desalination capacity of 400 liters per second. The mine achieved a water recirculation rate of 80% in 2025. 
To further reduce its reliance on continental water and enhance the resilience of future operations, the mine is expanding the desalination plant to double its production capacity from 400 to 800 liters per second. The project is targeting completion in 2027.

Antofagasta Minerals is also working to standardize water management across its operations and has appointed Water Leaders at each site to support the implementation of water management practices and monitor compliance. In 2025, more than 70 employees across the Group participated in training on water management and related standards. The company also implemented a centralized system that provides real-time visibility of the water balance at each operation. 

At the Escondida Mine, investment in seawater desalination infrastructure and the recovery of water from operational processes are key elements of its water strategy. In addition to reducing water consumption through water conservation, recovery and reuse, the mine invested US$ 3.43 billion, including associated water conveyance and power infrastructure, to develop a seawater desalination plant with a production capacity of 2,500 liters per second.
Since groundwater withdrawal from the Monturaqui borefield ceased in the second half of the fiscal year ended March 2021, the mine’s operational water requirements have been met entirely with desalinated seawater, except for small quantities of groundwater extracted through pit dewatering to support safe mining operations