Anglesey Mining has entered into a memorandum of understanding (MoU) with Swedish energy storage company Mine Storage International AB to investigate conceptual plans and designs for a pumped hydro-energy storage project at the company’s 49.75% owned Grängesberg iron ore mine after mining ceases.

Pumped-hydro storage is a green-energy storage solution that uses water and gravity to store electrical energy. An underground mine can provide a closed-loop solution using proven, pumped hydro-power technology, according to the company.

Essentially, the system involves water being gravity fed through pipes down a shaft into the turbines, which produce electricity for supply to the grid and also pump the water back to surface. The mine storage system reportedly has a high round-trip efficiency of 75-85% and proven durability.

The MoU, Anglesey says, could lead to numerous future benefits including:

• A potential long-term revenue stream from the Grängesberg Mine to enhance the cashflow and net present value;
• Enabling the circular economy with existing technology, turning a depleted mine into a power storage asset ensuring generational benefits; and
• Partnering with a well credentialled Swedish partner and potential exposure to Scandinavian investors

Jo Battershill, Chief Executive of Anglesey Mining, said: “We are very pleased to have signed this MoU with Mine Storage over our Grängesberg project. The Mine Storage team has identified the Grängesberg Mine as one of the most suitable locations to design, install and operate what could potentially be a significant pumped hydro-storage project.

“As we have stated previously, we believe the Grängesberg project provides substantial strategic value and has the potential to be restarted as one of Europe’s largest individual producers of high-grade iron ore concentrates. We continue to investigate ways to advance the project through to a Financial Investment Decision, which may involve securing a strategic investor, offtake partner, separate listing, or a combination of these options.

“Any potential to convert the mine into a long-term source of hydro-storage power only adds to the strategic value of the asset. We look forward to working with Mine Storage on the options for integrating a pumped hydro-storage solution into the mine plans.”

Thomas Johansson, Co-founder and Chief Executive of Mine Storage International, commented: “This collaboration with Anglesey is a great confirmation of the value Mine Storage can offer not only in the global energy transition, but also for a sustainable mining industry. Anglesey Mining and Grängesberg Iron show a great leadership and we are both pleased and honoured to have entered into this collaboration with them.”

A prefeasibility study from July 2022, which envisaged a restart of Grängesberg in central Sweden, highlighted potential production of 2.3-2.5 Mt/y of iron concentrate grading 70% Fe. This was from a mine able to operate at an average rate of 5.3 Mt/y for 16 years.