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Geotechnical News • September 2013
33
WASTE GEOTECHNICS
Collaborative research at Diavik Mine provides environmental
considerations for Canada’s next northern mining projects
Vivian Giang
On July 19, 2013, Northwest Territo-
ries’ Mackenzie Valley Environmental
Impact Review Board approved the
Gahcho Kue Diamond Project, with
some environmental conditions. If
approved by the federal government,
Gahcho Kue will become Canada’s
fourth diamond mine, joining Ekati,
Diavik and Snap Lake.
As more northern mine projects are
being proposed in Canada, many won-
der what the environmental impact of
such projects may be and how best to
mitigate any risks. In 2003, research-
ers at Canada’s leading universities
teamed up with industry and engineer-
ing consulting firms to investigate the
environmental impact of waste rock
at the Diavik Diamond Mine. Ten
years later, this collaborative, multi-
disciplinary research provides many
insights into the special considerations
that must be taken into account when
mining in permafrost regions.
During excavation, mine operations
create waste rock that has to be stock
piled and has the potential to gener-
ate acid rock drainage (ARD) when
oxidized minerals and dissolved
metals are released or are carried into
groundwater and surrounding lakes
through rain or snowmelt. This can
cause great environmental harm to
northern Canada’s fragile ecosystems.
In hopes of reducing such environ-
mental risks, Diavik Diamond Mines
Inc., a subsidiary of Rio Tinto, the
University of Alberta, University of
British Columbia and University of
Waterloo began discussions on the
design, construction and instrumenta-
tion of field-scale experimental waste
rock piles at Diavik as mine operations
began in 2003.
The Diavik Project is located 300 km
north of Yellowknife, NWT, in a region
characterized by continuous perma-
frost. Three 15 m high waste rock test
piles of various sulphur content levels
were constructed between 2004 and
2007. Two of the piles were uncovered,
and one pile was covered with a 1.5 m
layer of till and then a 3 m layer of non-
acid generating waste rock. These piles
were heavily instrumented to measure
water flow and water chemistry; inter-
nal pile gas composition; temperature
within the test pile; and thermal con-
ductivity and air permeability. A series
of comprehensive research papers
regarding the Diavik Waste Rock Proj-
ect, its set up and the experiments con-
ducted on the waste rock piles has been
published in
Applied Geochemistry
and
can be accessed online (see references;
many other papers were published in
other journals and conference proceed-
ings, but are not listed).
Dr. Nam Hoang Pham remembers the
first time he set foot in Diavik in April
2007. “We had just finished the winter
season in Edmonton, and I was look-
ing forward to experiencing spring in
the Northwest Territories. But it was
-30°C!”
Figure 1. Aerial view of the test piles at Diavik Diamond Mine (Pham 2013).