Person analyzing volumetric moisture content as material calibration for soil sensors (Okane Archive)

Shifting to Dry Stack Tailings Management

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Background

A mining operation transitioned its tailings management from exfiltration ponds to dry stack tailings storage facilities at two mine sites, which collectively hold 15% of the world's known tungsten reserves. Okane was initially engaged to conduct a study assessing both current and proposed tailings containment areas. The objective of the study was to reduce net percolation and oxygen ingress, which can produce acid mine drainage (AMD) and provide a closure surface that would harmonize with the surrounding landscape.

Approach

To support the transition to dry-stack tailings management, Okane suggested establishing a demonstration site as it was important to demonstrate an understanding of how the facilities would be reclaimed. This demonstration site aims to assess cover system performance during operations and after closure, addressing uncertainties related to energy balance, water balance, chemistry, and the geotechnical and geochemical aspects of landforms.

Client Benefit

The study, instrumentation program, and numerical modelling analysis confirmed that certain existing cover systems are performing well and will continue to do so in the future. The conceptual modelling analysis demonstrated that sufficient levels of saturation could be maintained to minimize sulfide oxidation and contribute to keeping facility seepage near circum-neutral pH.

Okane Archives.

An aesthetically pleasing landform design that achieves cover system performance objectives for dry stack tailings facilities.