New filtration technology can eliminate tailings dams

Reuse 95 percent of the process water and eliminate the need for tailings dams. Colossal™ filters from FLSmidth make dry stacking possible for large mines. Learn how when we present the solutions at PASTE 2018.

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Minimise the inflow and use of water, and eliminate the risks associated with tailings dams. These two concerns should be on top of every mining company’s risk list. At PASTE 2018 in Perth, Australia, FLSmidth will present a solution that addresses these concerns and is a step change in water management.

Colossal™ filters recover 600 m3 water per hour – Wednesday April 11 at 10:50
On Wednesday 11 April you can hear about our AFP-IV Colossal™ Filter. The AFP-IV is a filter press, which uses high pressure and fast filtering to achieve a much larger single machine capacity than other filter types. It is capable of discharging 20,000 tonnes of filter cake per day and can recover 600 m3 of process water per hour, making it a viable solution even for large mining operations.

“It is a breakthrough in filtration technology. Some mines produce well over 100,000 dry tonnes of tailings per day, and dewatering this massive volume using old technology would require football fields of filters. To cover the need of 150,000 tonnes per day, we would need ten filters in operation. In arid climates, the amount of water saved covers the costs of this solutions – and that is before we start to talk about the environmental and energy saving benefits,” says Todd Wisdom, Director of Tailings Systems in FLSmidth.

Eliminate tailings dams
The greatest environmental benefit is the elimination of tailings dams. 95 percent of the process water can be reused after filtration, and after the dewatering process in the filter, the moisture content in the dry cakes will be 15-20 percent, depending on ore type and varying over mine life.

Together with Goldcorp, FLSmidth has developed a low-energy and low operating cost solution for co-mingling these dewatered tailings with waste rock. The solution is called EcoTailsTM, and the material produced by this co-mingling process is called GeoWasteTM. GeoWaste makes dry stacking possible even in areas of high seismic activity.

GeoWaste, safe stacking for large mines - Friday April 13 at 14:20
On Friday 13 April you can hear Todd Wisdom explain the process and quality of GeoWaste.

“We fill the voids of the waste rock matrix with filter cake. This creates a material that is easy to convey and has a high strength when stacked. Furthermore, GeoWaste greatly reduces oxygen flux. We get a co-mingled waste that is both geochemically and geotechnically stable. We avoid seepage of chemically sensitive liquids, and in earth quake prone areas GeoWaste is a much safer solution than tailings dams,” he says.

Meeting future requirements for sustainable water management
Combining the AFP-IV Colossal filter and the EcoTails solution makes dry stacking possible and financially competitive for large-scale mining. It also meets future requirements for sustainable water management and tailings storage.

“The target for the industry should be to eliminate tailings dams and recirculate maximum water back into the process. Dry stacked tailings is the sustainable route for tailings disposal, and I am very much looking forward to present these solutions at PASTE 2018,” says Todd Wisdom.