Grout Curtain Installation for Sump Excavation in Permafrost Region of Northern Canada

As part of an expansion of a tailings facility infrastructure located in northern Canada, a grout curtain was installed at the location selected for a future sump expansion to reduce any potential inflow of water from a lake located immediately adjacent to the sump. Curtain installation included treatment of both the overburden and upper and lower fractured bedrock, and interface treatment carried out through use of sleeve port pipe technology. Challenging ground conditions that included poor quality, frost shattered bedrock required that a combined solution of consolidation grouting and downstage techniques be applied to reach the target curtain depth. An additional challenge was the need for rapid grout thickening and volume limit protocols combined with continuous environmental monitoring while injecting in close proximity to the lake. This paper summarizes the grouting program, challenges and solutions, and successful implementation of environmental monitoring techniques. The site is located in an isolated area of northern Canada and is accessed either by aircraft or by winter ice road.