The Alaska Contractor - Summer 2008

for the project. Coeur asked regulators to
consider using an alternative site for tailings
disposal near Comet Beach on the
Lynn Canal side of the project, a location
that was previously approved for tailings
disposal by state and federal regulators.
“This process has been going on for
a long, long time,” said Rich Hughes,
development specialist in the state’s Office
of Economic Development/Minerals.
“The cost of placing tailings in that location
was quite high, so the company and
regulators chose to permit the Slate Lake
site for tailings. That plan, was, of course,
opposed and stopped.”
In its new plan, Coeur proposes using
paste technology, rather than drystaking
the tailings. Plans call for pumping
slurried tailings through the tunnel
from the mill site on the Jualin mine
side of the Lion’s Head Mountain to the
Lynn Canal side of the property. A paste
plant will produce a tailings mixture
containing about 25 to 30 percent water
that will be stored behind a berm on a
terrace on the Comet side of the project.
About 40 percent of the tailings will be
used for mine backfill through the life of
the mine.
The tailings will be thick, “similar to
toothpaste,” explained Jan Trigg, Coeur
Alaska’s manager of community relations
and government affairs. “They will
be placed in the tailings facility behind a
berm, which will be engineered to dam
design standards.”
Estimated costs for the revised tailings
disposal process are currently being
developed.
Construction of the Kensington gold mine
northeast of Juneau included development
of the Slate Creek Cove dock facilities. If the
mine’s developer, Coeur Alaska, can secure new
permits for tailing storage and gold processing
begins next year as anticipated, workers for
the underground hard rock gold mine will be
transported by boat to the new job site.