Lake Shore Gold Shear Key Design Project

The Challenge

In 2018, our client Lake Shore Gold was operating a large gold mine in Northern Ontario and needed to raise the water level of a nearby dam in order to increase the size of their tailing pond - an open-air facility used to safely store the water used in their operations.

The challenge was that raising the water levels of a dam can potentially result in structural instabilities that can cause damage to the infrastructure and potentially nearby areas.

The Solution

With in-house engineering capabilities, Marathon has a keen understanding of geotechnical design and was able to blend that expertise with practical experience to improve upon designs, saving both cost and project schedule.

The solution for Lake Shore Gold was to change methodologies from a soil mixing option to a 280-metre long rock fill shear key – a system used to increase the stability of a dam.

An excavated trench was then implemented using traditional civil equipment and trench boxes. This methodology eliminated the need for an expensive working pad to be created onsite, as well as the need for expanded access roads at the mine site to build the working pad.

Once the shear key was excavated, existing onsite waste rock - which was plentiful and added no cost - was used as fill into the trench.

The methodology change was an open book and collaborative process with the existing design engineer and all supporting materials were shared and confirmed. Marathon completed the project in just 42 days.

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