Faro mine closure

Challenge

The Faro Mine is a historic lead-zinc mine that is currently under closure, managed by the Canadian Federal and the Yukon Provincial Governments. It extends over a 10 km long area and includes 300 million tons of waste rock, much of which is acid generating and many million tons of tailings that were hydraulically deposited.

Solution

The Faro deposit is a stratiform lead-zinc-silver deposit which straddles a contact between the non-calcareous phyllite and schists and calcareous phyllite and calc-silicates. Major minerals include sphalerite and galena. Seven different types of sulfide rock have been identified and are generally quartz with pyrite, phyllite, chalcopyrite, marcasite and others.

The current mine site includes a large open pit, 258 million tons (MT) of mostly acidic generating tailings placed in a creek bottom. The waste rock contain an average sulfide content of 13% (ranges from 0 to 100%).

As a member of the IPRP, SLR team is actively reviewing and directing the closure studies and designs at the Faro Mine Site (FMS). Closure studies and elements include but are not limited to characterisation of the acid conditions and acid seepage flow calculations to ensure the most effective waste rock cover types, design of clean-water surface diversion systems, impacted runoff and seepage collection wells, trenches and stream beds, grading and selective covers for waste rock and the tailings facility closure and long term water
treatment.

Impact

The FMS closure is one of the largest mine closures in Canada.