68th Canadian Geotechnical Conference and 7th Canadian Permafrost Conference

GEOTECHNICAL INVESTIGATION AT THE LONG LAKE CONTAINMENT FACILITY, EKATI DIAMOND MINE, NT

Session: Mining Geotechnique III / Géotechnique minière III

Gary Koop, Tetra Tech EBA Inc. (Canada)
Elizabeth Garven, Tetra Tech EBA Inc. (Canada)
Lukas Novy, Dominion Diamond Ekati Corporation (Canada)

The Long Lake Containment Facility (LLCF) at the Ekati Diamond Mine (Ekati) is the primary containment area for processed kimberlite generated during diamond ore processing. In the winter of 2013, a geotechnical investigation was completed in the LLCF to investigate the in situ conditions of the processed kimberlite (PK) and to evaluate permafrost growth in the facility. Continuous core samples were obtained with a sonic drill rig. Geotechnical and geochemical testing was completed to characterize the material. Investigation results indicate significant permafrost growth in the LLCF, with unfrozen material encountered at the southern limits of the investigation area where recent processed kimberlite deposition has occurred. Geochemical testing on recovered samples suggest some expulsion of solutes during the freezing process.

This paper provides an overview of the investigation and summarizes the geotechnical and geochemical test results. Comparison with previous investigation results are also made to evaluate historical permafrost growth and material variations within the LLCF.