Magnon Green Energy and Sandfire MATSA Lead Spain’s First Circular Economy Project Reusing Biomass Fly Ash in Underground Mining

• This is the first by-product authorisation granted by the Regional Government of Andalusia.
• This pioneering initiative, endorsed by the University of Huelva and verified by LOEMCO, reinforces both companies’ environmental commitment to the region.

Magnon Green Energy and Sandfire MATSA are launching a ground-breaking project in Spain that will enable the reuse of biomass fly ash as a partial substitute for cement in the backfilling of mining chambers and galleries. This represents an unprecedented step forward in the Spanish mining sector, further strengthening both companies’ commitment to industrial innovation, efficiency, and the circular economy.

The initiative involves the progressive incorporation of fly ash generated from biomass processes as a cementitious material in the production of paste used to fill underground chambers and galleries. These ashes, previously considered waste, have now been officially classified as a by-product by the Andalusian Regional Ministry for Sustainability, Environment and Blue Economy, allowing for their specific use in two of Sandfire MATSA’s mines: Aguas Teñidas and Magdalena, located in Almonaster la Real.

Collaborative Work

The detailed process has received technical endorsement from the University of Huelva and has also been validated by LOEMCO (Official Laboratory for Construction Materials Testing) following five years of collaborative work between Sandfire MATSA and the Sustainability and Circular Economy division of Magnon Green Energy.

In this regard, Andrés Castilla, Head of the Backfill Department at Sandfire MATSA, explains: “This solution turns waste into a resource, reduces emissions, optimises processes, and strengthens our ties with the region. This project allows us to continue progressing towards more sustainable, responsible, and environmentally respectful mining.”

Meanwhile, Paloma Lastra, Director of QHSE and Sustainability at Magnon Green Energy, highlights: “This initiative exemplifies our commitment to the circular economy, which is an essential part of Magnon’s DNA. It actively contributes to reducing the environmental footprint and promotes local development.”

In this way, Sandfire MATSA and Magnon Green Energy are leading an unprecedented initiative from Huelva, transforming a waste product into a by-product and giving it a new lease of life as a raw material in another production process.

Improved Strength and Durability

Tests carried out by the Sandfire MATSA team and verified in both national and international laboratories (including LOEMCO, Elabora, and CEMOSA) demonstrate that the paste resulting from the mix of cement and biomass fly ash maintains—and in some cases improves—its strength and durability, thereby enhancing its long-term performance and safety.

On fly ashes

The generation of renewable electricity from biomass produces ash with cementitious properties that can be used in processes such as those at Sandfire MATSA, significantly reducing the environmental footprint and avoiding the use of non-renewable resources.

The circular economy is the core of this initiative, which not only avoids the need to manage this type of waste but also reintroduces it as a new raw material into the production chain, creating an industrial symbiosis between two key sectors in the province: energy and mining.

As part of this project, Sandfire MATSA needs to adapt its facilities to store fly ash at its paste production plants in Aguas Teñidas and Magdalena. This action represents a further step in the modern mining model the company is promoting in the province of Huelva, with projects that generate shared value for industry, the environment, and neighboring communities.