68th Canadian Geotechnical Conference and 7th Canadian Permafrost Conference

RECLAMATION OF MATERIAL SITES IN CONTINUOUS PERMAFROST OF ALASKA: AN EXAMPLE OF GROUNDWATER FLOW BETWEEN PITS

Session: Mining Geotechnique III / Géotechnique minière III

Eva Stephani, Golder Associates (États-Unis)
mark musial, Golder Associates (États-Unis)
steve anderson, Golder Associates (États-Unis)

Development of material sites in northern Alaska can result in multiple pits separated by buffer zones with some pits partially filled with water as they are reclaimed. This common reclamation concept relies on cold frozen ground to prevent hydraulic connection between the pits. However, mining operations and the presence of water bodies that do not entirely freeze in winter can trigger changes in the thermal regime. As a result, groundwater flow paths can develop in the buffer zone separating the former and active pits. This paper presents a case study example where groundwater flow through a buffer zone separating a pit in reclamation and an active pit was assessed using a combination of geophysical methods and borehole data. Preliminary review of the instrument data results suggest that the reclamation concept, which allows pits to be filled with surface water while adjacent pits are still active, should be assessed and possibly modified.