DELIVERING SUSTAINABLE OPTIMISATION
T KSS Multi-Sensor Systems
n Energy Costs and ve Process Efficiencies
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DRA GLOBAL: HELPING MINING COMPANIES REALISE THE BIG PICTURE FOR THEIR PROJECTS
DECEMBER 2019
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DRA GLOBAL
DRA GLOBAL IS DELIVERING INNOVATION TO THE MINING SITE, TURNING UNDERPERFORMING PROJECTS INTO OUTSTANDING ONES
D
RA Global (DRA) is a diversified global engineering, project delivery and operations management group. Founded
in 1984, its impressive track record spans over three decades. With expertise in the areas of 04
project development, mining, mineral processing, plant optimisation, operations & maintenance and related water, energy, and infrastructure requirements, the company successfully delivers comprehensive solutions to the resources sector. DRA has detailed design and construction at its core but also supports major innovations to drive cost savings at the PEA (Predicted Energy Assessment) level while focused on guiding these projects through to construction. Brent Hilscher, DRA’s Director of Process for Western Canada, was brought in to broaden the company’s global footprint and start its Vancouver office. Expanding DRA’s impressive array of services, Hilscher brings expertise in ore sorting, floatation, grinding and extraction. “Typically, when you look at a block model, there won’t be huge DECEMBER 2019
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DRA GLOBAL
C O M PA N Y FACT S
• 4,300 staff worldwide • 4,500+ projects completed globally • 3 decades of experience
variability in the grade of the deposit and every block looks like it’s 100% ore,” he explains. “But, when you take that block and you crush it, you normally find that half of the rocks that leave your gyratory are waste rocks. Extraction is a resource and cost intensive process, so, there’s a lot of potential to take that crushed material and reject a certain amount, allowing us to boost mill feed grade while using less power and water.” DRA employs many distinct technologies for bulk and particle sorting. For bulk sorting prompt gamma neutron
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activation analysis (PGNAA) is one of the most common, where the ore is scanned and exposed to neutrons. Gamma rays are re-admitted from the
“ EVERY ROCK IS SCANNED INDIVIDUALLY WITH TECHNOLOGY CAPABLE OF ANALYSING EACH PARTICLE TO TELL YOU WHAT’S ORE AND WHAT’S WASTE” — Brent Hilscher, Director of Process, Western Canada, DRA Global
DECEMBER 2019
ore with specific signatures a result of the atoms contacted which can, for example, reveal how much copper is in the ore on the conveyor. “Particle sorting is where I probably spend most of my time,” adds Hilscher. “Every rock is scanned individually with technology capable of analysing each particle to tell you what’s ore and what’s waste.” During this process, a variety of sensor methods are used to improve efficiency. “Dual energy
CLICK TO WATCH : ‘DRA GLOBAL OVERVIEW’ 07 x-ray transmission (XRT) looks at
gold ore, it could be that the estimated
the density of particles and does so
gold value is determined based on iron,
by compensating for the size of the
titanium, and zirconium, things you
rock using two energy levels of x-ray,”
might not often think of being associated
explains Hilscher. “The technology has
with gold,” adds Hilscher. “It could
advanced to the point where we can
also be that the waste has a certain
look at the density profile of a block
quantity of things that the ore does not,
rather than the average density of the
so you could create reverse correla-
rock and use that characteristic profile
tions with the XRF.” Other techniques
to tell the difference between ore and
include the use of lasers which assess
waste.” DRA also deploys XRF, which
the brightness of the rock and its
provides a profile of the heavier ele-
translucent characteristics. However,
ments and can detect copper, lead,
not all approaches are fruitful. Hilscher
zinc, titanium, zirconium and more to
has worked on more than 40 major
help determine the ore’s value. “If it’s a
projects, where his team have had little c a na da .busi ne ssc h ief. com
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DRA GLOBAL
CLICK TO WATCH : ‘BRENT HILSCHER FOR DRA GLOBAL’
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success with electromagnetic sensors,
metric for operations where, for example,
and admits that “you want to keep an
we’ll look at how much gold or copper
open mind but some techniques work
is recovered at the end of the process.
better for certain ore types, so it’s
When we do ore sorting, we’ll often
important to match the right analysis
throw away 5% or more of the valuable
approach to the specific site”.
minerals, so we developed a metric to
Allied to the practical dynamics of
learn the actual value of what’s being
the sorting process, Hilscher believes
lost where the operating costs for
ore sorting economics are crucial.
the extraction and tailings facilities
“Building an economic model for every
are incorporated into that recovery
project tells us what the optimum
number. Discarding a low-grade rock
operating conditions are going to be.
would have a positive impact on profit
A key metric is profit recovery.
recovery, which rewards us for throwing
Normally, metal recovery is a driving
away rocks we’re losing money on.”
DECEMBER 2019
Preparing an economic model for
payback period for a specific project.
each project helps DRA build the best
“For Brownfield projects we’re usually
algorithm to support the second phase
targeting a payback of six months,”
of testing with a bulk sample. “The eco-
says Hilscher. “That seems to be what
nomic model is able to show us the best
mining companies are looking for
sorter operating conditions,” confirms
these days and it’s certainly achievable
Hilscher. “We can see the best upgrade
for a lot of these ore sorting projects. For
ratio for the ore sorter to be running at,
Greenfield, it’s even easier because
so that once we get into the large-scale
your CAPEX is so much lower. For
test, we’ve got the correct algorithm
example, for a single sorter Brownfield
and operating setpoints for the deposit.”
system, it might cost $5mn to install a
That test work and algorithm sup-
200 tonne per hour system, but with
ports the economic model, allowing
the ore sorting equipment incorporated
DRA to more accurately define a
into your design at the beginning of
E XE CU T I VE PRO FI LE
Brent Hilscher Brent Hilscher has 20 years’ experience in mining and mineral processing. He has operated and supervised mineral processing plants, published papers, patented technologies, and been a speaker at over a dozen conferences and universities in Canada and around the world. Brent has led design and construction projects for Teck, Goldcorp, New Gold, Barrick, Xstrata, Agnico Eagle, and many others. He won the CMP Bill Moore Award for technical excellence in 2013, and served as an officer in the Canadian Armed Forces.
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STEINERT KSS Multi-Sensor Sorting Systems
Save on Energy Costs and Improve Process Efficiencies High-throughput sorting of Industrial minerals, ores, and precious gemstones
Coal, iron ore, copper, tin, gold, mineral sands, precious gemstones, non-ferrous metal ores, manganese ore, aluminum, ferro-chrome, industrial minerals... These are just a few of the valued resources the STEINERT KSS system helps recover, sort, and separate. The system utilizes an array of ore-processing sensor Depending on particle size range, the STEINERT KSS can process up to 150 tons per hour. Adjusting machine sensitivity and accept/reject cut-off grade provides the flexibility to boost high upgrade ratios or maximum recoveries.
technology combinations, including: X-ray transmission (XRT); X-ray
Focusing on pre-concentration adds previously uneconomic zones to ore and mineral reserves, and improves the effectiveness of ore blending management programs. Processing low-grade stockpiles, even waste dumps, and selective upgrading generates value from previously uneconomic material. This leads to reduced tailings, less environmental impact, reduced milling energy requirements — all which add value to the life of the operation.
fluorescence (XRF); induction; optical-color and 3D laser.
STEINERT US
285 Shorland Drive Walton, KY 41094 1.800.595.4014 SteinertUS.com sales@SteinertUS.com
The STEINERT test center in Walton, KY, provides real-world, real-time tests of our many sorting solutions for today’s ore-processing needs. We welcome the opportunity to discuss your specialized application requirements.
“ 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 THEM SEE THE BIG PICTURE” — Brent Hilscher, Director of Process, Western Canada, DRA Global
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 we scanned the rock with a conservative approach only throwing away 60% of the rock to begin with. We eventually achieved double the feed grade, with over 95% silver recovery.” DRA has worked for many years to develop approaches to dense media
construction, the cost can be halved.”
separation (DMS) that use fluids of
In greenfield designs there is also an
suitable density so that the minerals
opportunity to reduce project capital
lighter than the fluid float and those
while maintaining or increasing designed
that are denser sink. Hilscher’s team
production. Hilscher notes that instead
is also developing conservation tech-
of spending $100mn on a new mill, a
nologies to meet the changing needs
smaller mill with sorters could produce
of the sector. “Ore sorting is just part
the same product for $70-80mn.
of our tool kit for project revitalisa-
“Spending a little more on your ore sort-
tion. DMS coarse particle recovery,
ing system up front can lead to a clear
modular construction and many others
win for the overall project,” he confirms.
are looked at for each new project. c a na da .busi ne ssc h ief. com
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DRA GLOBAL
Bel Air Bauxite
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In 2017 DRA Global was awarded the contract for the development of a port facility and associated infrastructure for the export of bauxite, by Alufer Mining in Guinea. The Alufer Bel Air Mine project was DRA’s first causeway development, which expanded the company’s exposure within the marine environment. Bel Air was expected to have an initial production rate of 5.5 million tonnes per annum and included a 22.5km haul road running over eight river crossings, an export facility with the ROM tip that feeds a 6500-tonne live capacity stockpile, and a causeway extending 1.4km into the Atlantic Ocean, where a barge load out berth was constructed.
DECEMBER 2019
The scope included all the necessary infrastructure to operate the facility: construction camp, wellfields, power generation, offices, laboratory, workshop and a bailey bridge across the Koundinde Work on the project commenced in January 2017 and was completed in August 2018 before commercial production was achieved within the first six months of operation. Alufer is on target to reach its annual production rate of 5.5 million wet tonnes by the end of 2019. DRA Global’s extensive material handling, earthworks and infrastructure design capabilities have contributed significantly to the success of the project.
15 Hydrofloat is a new coarse particle
so they can test solutions in their own
recovery flotation technology, which
operations.” The solutions DRA offer
we’ve started installing for clients,” he
leverage the company’s relation-
confirms. “It uses the slurry current to
ships with key tech partners including
assist in the flotation of exceptionally
Tomra, Steinert, Eriez, Scantech,
coarse particles.”
Rados, Minesense and others.
Hilscher notes that mining has his-
Safety is a hot topic in the industry
torically been hesitant to innovate but
today. Given the tragic impact of
the adoption of ore sorting technolo-
recent dam failures in Brazil, Hilscher
gies into the mainstream has proved
is particularly interested in developing
the exception because the results
DRA’s services to provide alternative
are so dramatic. “It comes down to
tailings solutions. “We’ve done a lot
education,” he says. “We need to make
of work on dry stack tailings, which is
mining professionals aware of the
becoming a more popular option for
benefits from emerging technologies,
plants,” he says. “Even within dry stack c a na da .busi ne ssc h ief. com
DRA GLOBAL
designs, there are optimisation opportunities. Instead of sending all the tailings sand to a filter plant, you may have a two-stage cyclone plant first. The coarsest fraction is used for roads and earthworks, the fine fraction goes to the existing tailings pond (or co-disposal piles), and the mid-size material is filtered. This compromise reduces tailings pond sizes by two thirds while also removing most of the fines and clays that are so difficult to filter. “Of course, sensor sorting, DMS, and 16
coarse particle flotation all have a tailings pond benefit because if you can take those worthless rocks and keep
“ BUILDING AN ECONOMIC MODEL FOR EVERY PROJECT TELLS US WHAT THE OPTIMUM OPERATING CONDITIONS ARE GOING TO BE” — Brent Hilscher, Director of Process, Western Canada, DRA Global
DECEMBER 2019
them coarse you are able to put them in a waste pile or road bed. That’s a direct reduction to your tailings pond size. The pond dam won’t need to be expanded as often, and that tends to make them much safer,” he adds. Hilscher believes that in order to drive innovation, all metrics and operational concerns need to be addressed. It’s a weighty issue where he argues a balance must be struck. “Metallurgists tend to be worried about recovery. Geologists are concerned
1984
Year founded
4,300 Number of employees
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about ounces and pounds in the
achieve all of these goals simultaneously.
ground. Mining guys are focused on
We can drive growth, while making
tonnes, while CEOs are counting the
tailings ponds smaller, use less water,
dollars,” he muses. “I’ve found that
less energy, and produce less CO2.
the economic model does a great job
All of this simply by rejecting the
of bringing all those people together
worthless rock earlier in the process.
and helping them see the big picture.
It’s the future for sustainable mining
How do the ounces, tonnes, and
and something we’re really excited
recovery feed into making a deposit
about at DRA Global.”
as economical as possible? What can we do to reduce the environmental impact and also make the mine more profitable? With ore sorting, and other preconcentration techniques, we can c a na da .busi ne ssc h ief. com
www.draglobal.com