Multinational miners BHP and Rio Tinto have formed a partnership agreement to accelerate the development of technology that could significantly increase water recovery from mine tailings, and in turn, reduce potential safety risks and environmental footprints associated with tailings storage facilities (TSFs).

The first project will involve testing the application of an innovative large-volume filter unit at a BHP copper mine in Chile, which would remove up to 80% of the water in the tailings stream before it is deposited in a TSF.

Rio Tinto will bring its experience from implementing smaller-scale tailings filters for bauxite residues at alumina refineries since 2005. Both organizations will work in collaboration with leading technology and equipment providers, technical experts, research groups and the academic sector.

“The world will need more critical minerals in the decades to come to support economic development and decarbonization pathways,” BHP Chief Technical Officer Laura Tyler said. “It is important that we keep working together across the global mining sector to raise standards and make sure our operations are as safe and sustainable as they can be. Responsible management of tailings and improved water use is a big part of that.”

Manufacture of the filter unit is already underway. The pilot construction is due to begin in early 2023 and operations are scheduled to commence in early 2024. The pilot will test the potential of a large-scale tailings filter unit for scalability and cost-effectiveness across global mining operations.

“It is in everyone’s interest that we, as an industry, find safer and more sustainable ways to manage tailings,” Rio Tinto Chief Technical Officer Mark Davies said. “As two of the leading companies in the sector, we want to bring our combined knowledge and expertise to address this challenge.”

Removing more water from tailings would reduce potential risks associated with moisture in TSFs, reduce the footprint required by TSFs, and create opportunities to productively re-use tailings, for example, as raw material for glass, construction or agriculture industries. The additional water recovered from tailings by filtration could be re-used in processing facilities, reducing overall water consumption.