A breakthrough solution from FLSmidth which combines filtered mine tailings with waste to form a GeoWaste also lowers water usage, rehabilitation costs and tailings footprints.
According to FLSmidth regional product line manager (Dewatering) Leonard Neluvhola, the Ecotails™ solution is nearing the end of a lengthy testing process by one of the world’s leading gold producers.
“The success of its application to date confirms that Ecotails will be a game-changer for the mining sector,” says Neluvhola. “Not only can mines improve their environmental performance by applying this system, they will also see bottom line benefits too.”
He says the Ecotails solution involves dewatering and filtering tailings to a point where moisture content is just 10% to 25%. “Up to 90% of the water in tailings can therefore be reused in the plant,” he says. “This is a vast improvement on pumping highly diluted slurry to a conventional tailings dam, where the water is lost to evaporation.”
The drier tailings are then mixed with the mine’s waste rock, after it has been sized and screened to be transportable by conveyor. The resulting GeoWaste can be placed by a stacking system, as it is much more stable than wet tailings and can be stacked higher on a smaller footprint. This helps to address the serious concern mines have about the large footprints consumed by their tailings dams and waste rock dumps.
In addition to its greater stability, GeoWaste is more conducive to vegetation growth. It is an ideal medium for concurrent environmental rehabilitation. The concurrent approach is becoming more popular, as it can mitigate the costs and risks of mine closure. Wet tailings can also present a greater danger of land contamination through leaching.
“With our Ecotails experience and complete system offering, FLSmidth can provide a complete materials handling solution,” Neluvhola says. This includes crushers, sizers and screens, KREBS® pumps, thickeners and filters, conveyor and stacking systems, conducting tests and studies, system engineering and automation systems.
Neluvhola highlights that FLSmidth in South Africa collaborates with customers on in-depth testwork to ensure the application of Ecotails on their mines is fit for purpose.
“We can conduct testing at laboratory scale, and then advance to pilot stage when a mini-plant can be operated on site,” he says. “This allows us to test the technology using the customer’s own mined material in the thickening, filtering, conveying and blending phases to inform our technical designs.”