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.
This is the amount 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.
Demonstrating genuine expertise in this field, the Group's sites utilize multiple revegetation techniques, including hydraulic seeding, planting and spreading topsoil.
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.
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.
Water consumption at Eramet sites in 2018:
- 50% surface water (water from the sea, rivers and lakes)
- 35% groundwater
- 11% industrial water (industrial-quality water supplied by an external provider)
- 4% drinking water purchased from a distribution network