K. Mcnaughton et Wj. Schlitt, Winter field test for heap leaching Carmacks copper ore in Canada's Yukon Territory, MIN MET PR, 17(3), 2000, pp. 186-193
A heap-leach field test was conducted during the 1993-1994 winter season at
Carmacks, Yukon Territory, Canada. The purpose of the test was to demonstr
ate the viability of heap leaching Carmacks oxide copper ore in an arctic s
etting on a year-round basis. The rest itself utilized a 5-m-diam crib load
ed with 250 t of composite ore from the Carmacks copper deposit The ore was
stacked to a total height of 7 m in the crib including 1 m of ore as an ov
er-layer above the emitter system. This matched the plan for the commercial
heap at the time when the test was started. The design also replicated an
interior segment of the commercial heap. Leaching was done at a flow rate o
f 0.2 L/min/m(2) using leachate at 21 degrees C. This temperature was maint
ained with no external heat input other than normal process heat transferre
d from electrowinning to the leachate via solvent extraction. Winter condit
ions were quite typical of those expected at the mine site. The temperature
leached -54 degrees C, while averaging -13 degrees C over a three month pe
riod. In spite of some flow system problems, leaching continued unabated an
d freezing was limited to the insulating ore ol er-laver and isolated point
s near the outer crib walls. Thus, the test demonstrated that year-round he
ap leaching of Carmacks copper ore is practical in an arctic setting.