Preserving water environments
Preserving the quality of water is a key challenge for our planet. However, Eramet's mining activity primarily takes places on outdoor sites, where ground clearing is a necessity and accelerates erosion. This is a particularly sensitive subject as most of the areas where the Group operates have heavy rainfall, such as New Caledonia.
The goal for SLN is to limit the risks of polluting the rivers or lagoon downstream of the mines with suspended matter, the solid particles present in natural and polluted water. Since the 1980s, the Group has developed key expertise in responding to this very specific issue. This know-how has resulted in various solutions being implemented, including the building of structures nearby mines to slow down then settle the rainwater. As such, SLN has fitted its sites with sedimentation tanks that can trap the suspended matter to prevent it re-entering the natural environment. A total of nearly 2,500 sedimentation tanks have been installed, all of which are now monitored by drones.
Ahead of these structures, multiple precautions are taken to limit erosion. The measures are documented for each mining site as part of a Water Management Plan. From rainfall to hydrobiology, chemical physics, suspended matter and piezometry, more than 300 monitoring stations are also active on the SLN sites to ensure these requirements are met.
21 million euros
This is the amount that has been invested over the last five years to improve SLN's water management.
To combat erosion, another solution involves revegetation at mining sites. This is why a goal of speeding up the rate of site revegetation was included in the Group's CSR roadmap.
From New Caledonia to Gabon and Senegal, the Group carries out mining rehabilitation actions, in particular by revegetating its sites (hydroseeding and planting, spreading topsoil, etc.). This is the most effective way to foster the return of biodiversity, as well as to combat erosion and thereby protect the quality of water resources around mining sites. In 2020, Eramet met its target for the 2019-2023 period with a ratio of 1.03: to rehabilitate at least as much land as the Group clears
Capping water consumption
Even though the Group's sites are usually located in areas with abundant water resources, major efforts are made to maximize water recycling and therefore decrease consumption.
In Gabon, the Comilog washery processes millions of tons of manganese. The site operates on a simple principle: firstly there is a washed – and saleable – ore, and secondly waste formed by the washing water and ultra-fine mineral particles. Eramet has implemented a water management strategy that involves settling the waste to recycle the water, which is then reintroduced into the process. Depending on the year, between 60% and 80% of the water used can be recycled.
In 2020, Eramet carried out a major study on the water footprint of all of its operating sites. The objective was to gain a more detailed understanding of the risks associated with the use of water in its various sites. To this end, the study relied on internationally recognized tools: Aqueduct Water Risk Atlas (developed by the World Resources Institute - WRI) and the Water Risk Filter. The study confirmed that no production site with significant water consumption (> 5,000 m3 per year) is currently located in a watershed at risk of high water stress, that is to say with a ratio greater than 40% between total water withdrawal and renewable and available water supplies as defined by the WRI.
Regarding mining sites, the issue of water consumption mainly concerns the Grande Côte Opérations site (GCO), in Senegal. Water management is a sensitive issue in this country as the operation of the mine uses two aquifers, one of which is very important to local inhabitants and the country in general. In light of this situation, every precaution is taken to reduce the impact of the mine as much as possible. GCO has an expert team in hydrogeology, and the water management system was designed and authorized by the competent department of the Senegalese Government to avoid any additional pressure on the superficial water table used to supply water to local residents' farm crops. All mining installations are controlled to ensure minimal variations in the level of this water table.
To anticipate the future scarcity of water resources, Eramet is also mobilizing to take into account the reduction in water intensity in all its development mining projects: taking into account the water factor was a key issue in the development of the adsorption process for the Lithium project in Argentina, making it possible to achieve a 30% reduction in the water intensity of the process as research and development progresses, and in turn allowing for a recycling rate of 60%.
With the exception of hydrometallurgical sites, the vast majority of the Group's water consumption is linked to industrial equipment cooling loops. The water consumed in these processes does not undergo any transformation. In addition, the vast majority of sites work in closed loops, which greatly reduces the demand. In other cases, the water withdrawn is returned to the natural environment.
The topic of minimizing water consumption is also central to R&D efforts by the Group to develop its own lithium extraction process. Through this initiative, a gain of over 30% water consumption per ton of lithium has been achieved over the course of the development.