Business Chief USA December 2019

“METALLURGISTS TEND TO BE
WORRIED ABOUT RECOVERY.
GEOLOGISTS ARE CONCERNED
ABOUT OUNCES AND POUNDS
IN THE GROUND. MINING
GUYS ARE FOCUSED ON
TONNES, WHILE CEOS ARE
COUNTING THE DOLLARS. I’VE
FOUND THAT THE ECONOMIC
MODEL DOES A GREAT JOB OF
BRINGING ALL THOSE PEOPLE
TOGETHER AND HELPING
Hilscher worked on a silver mine 12
months from closure due to constantly
declining grades. Ore sorting was
investigated to get the grades back up.
“We did the test programme, we got the
samples and discovered that nine out
of 10 of their rocks were below cut-off
grade,” explains Hilscher. “But one out
of 10 of their rocks was extremely valuable.
So, it was a very easy sort. We
could have used XRF, XRT, laser, any
one of those would have worked, so
THEM SEE THE BIG PICTURE”
we scanned the rock with a conservative
approach only throwing away 60% 219
of the rock to begin with. We eventually
achieved double the feed grade,
—
Brent Hilscher,
Director of Process, Western Canada,
with over 95% silver recovery.”
DRA Global
DRA has worked for many years to
construction, the cost can be halved.”
In greenfield designs there is also an
opportunity to reduce project capital
while maintaining or increasing designed
production. Hilscher notes that instead
of spending $100mn on a new mill, a
smaller mill with sorters could produce
the same product for $70-80mn.
“Spending a little more on your ore sorting
system up front can lead to a clear
win for the overall project,” he confirms.
develop approaches to dense media
separation (DMS) that use fluids of
suitable density so that the minerals
lighter than the fluid float and those
that are denser sink. Hilscher’s team
is also developing conservation technologies
to meet the changing needs
of the sector. “Ore sorting is just part
of our tool kit for project revitalisation.
DMS coarse particle recovery,
modular construction and many others
are looked at for each new project.
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