Construction of two large-scale waste rock piles in a continuous permafrost region

Abstract

The discovery of diamonds in Canada's North has led to renewed interest in the development of mining properties in the Arctic. At the Diavik Diamond Mine Inc. operation, open pit mining will lead to the construction of two 200 Mt permanent stockpiles of waste rock. A rigorous, quantitative framework for assessing the long-term environmental implications of storing waste rock in regions with continuous permafrost has yet to be developed. Our study involves the construction of two large-scale waste rock piles (15 m in height × 60 m × 50 m) to assess the evolution of the hydrology, geochemistry, temperature, and biogeochemistry of the waste rock piles over time. One test pile will contain rock with a sulfide content of < 0.04 wt% S and the other test pile contains rock with > 0.8 wt% S. Complementary studies involving conventional static and kinetic tests on small test samples have also been initiated. The results from this five-year study will assist mining companies and regulators in evaluating current waste rock pile designs. This paper describes the construction of test piles, preliminary modeling of heat transfer and oxygen transport within the piles, and additional testing planned to quantify the relationship between weathering rates in laboratory dissolution tests and those in waste rock piles in the field.