Water management

“Protecting the environment is a priority for us. Over the last few years, we have invested substantial amounts to address issues at their source. The communities around our operations are extremely important to us and we will continue to ensure that we are taking the right decisions to protect the environment.”

– Mapi Mobwano

President and CEO,
ArcelorMittal Mining Canada

Since 2017, ArcelorMittal Mining Canada has invested more than $400 million in comprehensive, long-term water control, water treatment, tailings and associated infrastructures. The objective was to permanently address operational and environmental water challenges, both on site and around its mining operations at the Mont‑Wright mining complex.

With these projects now completed, ArcelorMittal has addressed all the outstanding issues identified by Environment Canada. ArcelorMittal continues to implement initiatives designed to further strengthen its environmental stewardship and sustainable development practices.

NIPI Water Treatment Plant

The Nipi water treatment plant was constructed between April 2021 to March 2023, and full-scale operations began in April 2023. This plant is operated by a specialized operator from Quebec in partnership with the Innu Nation.

In tribute to the Innu people and the Nitassinan territory on which it was built, the facility has been named “Nipi,” which means “water” in the Innu language.

This project was part of a major mine water management program to facilitate adaptation to climate change and ensure compliance with environmental laws and regulations. Designed to treat suspended solids and dissolved metals in water with pH control, the Nipi project also included developing a system of channels and ponds around existing and future tailings piles to capture and treat all runoff south of the Mont‑Wright mine into a single final effluent to ensure that the water quality of this final effluent plant meets regulatory standards.

The Nipi facility treats approximately 10 to 12 million cubic metres of water per year, depending on annual precipitation. It was designed for a 100-year storm event and has a capacity of 6,500 cubic metres per hour. Its construction required 270,000 man-hours, and more than 4,000 cubic metres of concrete were poured.

Construction of Basin B+

Between 2021 and 2025, ArcelorMittal implemented a controlled containment and settling basin for water from its tailings deposited hydraulically, as well as from runoff in contact with these tailings.

Named “Basin B+”, this basin is a structuring component of the performance and stability of the containment system, which plays a key role in the hydraulic balance of the Mont‑Wright mining site. It helps to protect the integrity of the tailings storage facility infrastructure and management of the tailings volumes generated by the concentrator. It also prevents overflows of water directly into the environment that extreme rain could potentially cause, while controlling recirculation of water to the concentrator and assisting water quality in the final effluent.

Basin B+ has a capacity of 12.7 million cubic metres of water and extends over an area of approximately 4 km².

Development of Water Management Infrastructure – extension and construction of ditches

From 2017 to 2025, ArcelorMittal built a mine water management infrastructure to capture runoff and water from mining activities to a water treatment plant. The project involved:

• Extending an existing ditch (Ditch B) by 1.9 km
• Building a new 4.2 km ditch
• Adding a new water containment basin (Basin C) with a combined capacity of 170,000 m³

This project completed a previous project comprised of the construction of Basins A and B and Ditches A and B. These projects were designed and implemented to ensure compliance with federal and provincial regulatory requirements, and to protect sensitive natural environments downstream, such as Rivière aux Pekans and the projected Rivière Moisie aquatic reserve.

Expansion of Hesse North Tailings Facility

In 2023, the capacity of the Hesse North tailings storage facility was increased to support concentrator production and prevent overflows. The project involved raising the Hesse 4 dike to approximately 666 metres and the associated settlement structure, to increase the tailings storage capacity and ensure adequate management of tailings water in the tailing storage facility.

Completed at the end of 2023, this project was implemented to improve tailings and water management and eliminate the risk of uncontrolled spills into the environment.