Risk Mitigation through Design Optimization Utilizing Seasonal Effects under Arctic Conditions at the Amaruq Mine
Authors: Christian Tremblay1, Ben Peacock2, Véronique Falmagne3, K.S. Kalenchuk4, Erik Bellefleur5
Conference: Slope Stability 2024
Date: April 14-19, 2024
1 Agnico Eagle Mines Limited, North Bay, Canada
2 Knight Piésold Ltd., North Bay, Canada
3 Agnico Eagle Mines Limited, Rouyn-Noranda, Canada
4 RockEng Inc., Kingston, Canada
5 Agnico Eagle Mines Limited, Baker Lake, Canada
ABSTRACT
Agnico Eagle Mines is currently operating the Amaruq Mine located in the Canadian Arctic. Since the beginning of the open pit operations, a series of bench-scale failures and rockfalls have occurred during the freshet and summer months (May to September). These instabilities can be correlated with a prominent and very weak komatiite unit. The komatiite is an ultramafic rock commonly altered to a chlorite carbonate shist. The domain is strongly anisotropic and rock mass competency is highly variable. High strain zones within the komatiite, which are identified in core as zones of low RQD, with shearing or gouge are impacting the slope performance locally.
This paper presents the geological and geotechnical site characterization, emphasizing the challenging komatiite conditions including the impact of the high-strain structures. An overview of the historic slope performance and failure mechanisms is provided, with focus on the influence of the seasonal effect and how the mine plan has been adjusted to take advantage of more favorable frozen conditions. The evolution of the pit slope design in response to kinematic analyses and numerical modelling is presented as well as the strategic design updates and tactical measures implemented to mitigate risk through the life of mine.
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