The vast majority (approx. 87%) 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 0.6% of Group company sales. In the fiscal year ended March 2025, water withdrawal was 209 thousand m³ and water consumption was 273 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.

At Mantoverde Mine, the entire water supply for operations is provided by desalinated seawater produced at its own desalination facility. Agreements have also been signed with the local government and local water suppliers to ensure the supply of desalinated seawater to local communities.

Seawater withdrawal in 2024 was 14.6 million m³ (2023: 7.9 million m³), reflecting an increase associated with the commencement of concentrate production. The water-use intensity was 0.513 m³/tonne of ore processed (2023: 0.310 m³/tonne of ore), due to a rise in water demand resulting from the start of sulfide ore processing. As a result, 8.2 million m³ of brine (57% of the total amount withdrawn) was returned to the sea. This discharge complies with Chile’s “Norma de Emision DS 90,” the regulatory emission standard for liquid waste discharge to marine and inland surface waters.

At Los Pelambres Mine, water conservation and reuse are being promoted in the ore processing stage, with the target of sourcing 90% of operational water from seawater or recirculated water. To support this initiative, a seawater desalination plant began operations in 2024 and is expected to mitigate potential operational slowdowns during periods of drought. In 2024, approximately 58% of total water withdrawal was provided by desalinated seawater. The current desalinated water production capacity is 400 L/s, with plans to expand this capacity to 800 L/s by 2027, thereby further reducing external water withdrawals.

Additionally, as part of its contributions to local communities, 144 water sensors have been installed in communities surrounding the mine for the purpose of data collection to support the efficient and optimized use of water. Furthermore, in coordination with local authorities responsible for regional water management, a cumulative investment of 300 million Chilean pesos (approximately $350,000) was made in canal construction to improve water delivery to local communities.

To improve water efficiency, the mine has developed a plan with clear targets, including pilot testing and the optimization of the water balance in its operations. Water management responsibilities are assigned to Water Leads at the mine, who drive efforts to improve water-use efficiency. These Water Leads aim to enhance governance and develop internal skills within the mine by, among other actions, reporting monthly water-use performance, thereby promoting a cultural change towards sustainable water management.

At Escondida Mine, the world’s largest copper-producing mine, efforts to reduce water use through conservation and reuse have been complemented by an investment of approximately $4 billion in the construction of what is one of the world’s largest seawater desalination plants. As a result, since late 2019, the mine has eliminated all groundwater use, with 100% of the water required for operations supplied by desalinated seawater.