Waste Rock Closure Planning in Northern Climate: the Meadowbank Mine, Nunavut
Symposium 2015 Rouyn-Noranda
Mrs Érika Voyer (Agnico Eagle Mines Limited)
The Meadowbank gold mine of Agnico Eagle is located in the Kivallik region of Nunavut, approximately 110 km by road north of Baker Lake, the nearest community. In operation since early 2010, Meadowbank is currently operating three open pits and is moving over 100,000 tons of rock on a daily basis.
The end of mine operation is currently expected for the end of 2017. Reclamation planning was incorporated early in the mine development planning. Meadowbank mine includes three main waste rock piles, as well as open pit backfill areas. Since the early stages of production, the waste rock was separated according to its acid generating characteristics. Potentially acid generating (PAG) waste rock is disposed in selected piles and non-acid generating (NAG) waste rock is used for progressive closure purposes and the remainder will be reclaimed for post-operation closure purposes. Waste rock types show variable acid rock drainage (ARD) potentials, some of which may require control measures for mine closure. The control strategies to minimize the potential effects of ARD include natural freezing of the pile, progressive permafrost encapsulation during operation, as well as non-acid generating rock capping acting as a cold-insulating cover. On-going site monitoring has been established to verify the anticipated closure conditions and consequentially the validity of the proposed closure plan.