Abstract:

The global inventory of tailings is currently >55 billion m³ and is forecast to increase to almost 70 billion m³ by 2025. The cost of these tailings includes the construction and maintenance of tailings storage facilities (TSFs), the liability of catastrophic releases, environmental damages, and erosion of social licence to continue mining. Billions of dollars and decades of research have been spent searching for improved technologies to better dewater tailings and reclaim TSFs.

The EKS-DT process has been developed to dewater legacy and fresh tailings in situ, using electrokinetics. Over more than a decade of lab and field-scale testing has significantly improved its dewatering effectiveness and reliability and confirmed its commercial viability. A major innovation is the use of floating solar panels to power the electrodes. This innovation offers significant economic and environmental benefits. The process is less costly compared to current tailings management technologies and excels in its ESG performance. EKS has shown through a field demonstration that very fine-grained tailings (i.e. average particle size <6 microns) with an initial solids content of 20% (kg/kg) can be dewatered to >60% in less than two years.

EKS has also produced a forecasting model. The model accurately forecasts dewatering time and energy consumption for different designs and operating schedules, critical information for designing commercial installations.

A 1,700 m³ field demonstration from 2019 to 2021 proved that the technology is commercially viable. During this time, over 1,000 m³ of water was removed from the tailings and the energy consumption was <15 kWh per m³ of water released. The process was operated year-round through two harsh Canadian winters. The process operated as well during the ice-covered period as during warmer months. The installation was operated continuously 24/7 by the automated control system without an onsite operator. The design of the first commercial installations of the technology is now underway.

The engineering design process for the field demonstration and for commercial systems will be discussed, including the role of the EKS Model.

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Ed Hanna