Magino Mine Tailings map

Magino Mine Tailings Management Facility Design

Location

Wawa, Ontario

The proposed Magino Project is located in a sparsely populated area of central Ontario in Canada. The total proven and probable reserves are approximately 2.1 million ounces of gold. Up to approximately 550 tonnes of rock will be mined from an open pit; up to approximately 130 million tonnes of which is ore.

The detoxified tailings generated were demonstrated to be non-acid generating, but the tailings water would likely contain several metals of concern (e.g., copper, cobalt, and vanadium) and possibly levels of nitrate and cyanide that could affect the environment if not properly contained. A tailings management facility is included in mine waste management plan.

Our role

SLR performed geochemical and geotechnical field studies to develop design criteria and baseline conditions for the tailings management facility (TMF). SLR then developed a 30% level of design for the TMF that consisted of removing a thin layer of overburden soil to expose a granite bedrock foundation for the embankment, lining the inner face of the embankment with a flexible membrane liner underlain by filter and support layers, a system for tying the liner to the bedrock, seepage collection systems, and staged construction to account for the availability of construction material. Design studies performed by SLR include slope stability, water balance modelling, seepage flow modelling, groundwater flow modelling, material mass balances, geochemical characterisation of the waste rock to be used for embankment construction and the tailings, and a dam breach analysis. The embankment was designed based on the guidelines of the Canadian Dam Association. SLR also developed the closure plan for the TMF.

Highlights:

  • Construction in stages allows for early operation with concurrent construction of later stages when construction material becomes available and shifting of costs from capital to sustaining capital.
  • Staged construction also allows for expansion of the TMF should additional ore be identified or available based on revisions to the mine operations plan.
View of Magino site

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