COMMINUTION
AEGIS, iRing says, automatically generates all
the drill holes required for a stope according to
collar and toe spacing, and including burden
crushing could lead to annual savings in mines
and quarries of C$12.8 billion (25% reduction) to
C$25.6 billion (50% reduction).
The company said: “If all mines in the world
adopted this solution, it would represent a
reduction equivalent to
7-13% of all the carbon
released in Canada,
and 20-41% of
Canada’s contribution
to meeting the Paris
Accord agreement.”
iRing thinks AEGIS is
the right product to
front this energy saving
solution because of the
speed and accuracy it
offers drill and blast engineers.
Williams said: “Our product is probably five to
10 years ahead of the market…it is able to design
a stope in around a day, whereas it takes
competitors a few weeks.”
He continued: “It allows the drill and blast
engineer to focus on drilling and blasting and not
drafting (drawing lines on a screen).”
roduction capacity in the SAG mill is often the constraining factor
for an entire processing plant. Improving the throughput of a mill
by even a few percentage points can, thus, have a significant
impact on an operation’s bottom line.
Replacing steel cast liners with improved composite liners is doing just
that, according to FLSmidth, which used the backdrop of the recent SME
Annual Conference & Expo, in Denver, to tackle this topic with a special
presentation and product launch.
Jack Meegan, Product Line Manager for Liners and Wear Parts in
FLSmidth, said the dependence on equipment availability, and a low
appetite for risk in the mining industry, meant the progression of
composite materials into large SAG mill applications has been slow. “But
we are seeing more and more major copper and gold operations now
taking advantage of composite liners in large SAG mills,” he said.
For a customer in South America, FLSmidth recently replaced a
chromoly liner in a 40 ft (12.2 m) diameter SAG mill with a rubber ceramic
composite liner. This improved the slurry discharge by 6%, according to
FLSmidth.
“Many SAG mill liner designs perform very well in their objective to
achieve the desired particle size and protect the mill structure,” Meegan
said. “However, no matter how well a mill is operated, and no matter how
well a liner design performs, a mill is only as good as its ability to
discharge the slurry out of the mill.”
Changing the design of liners made from composite materials can
result in considerable throughput increase compared to standard steel
cast liners, according to Meegan.
“In this case (in South America), the benefit to the customer was of
seven figures in US dollars in just 12 months,” Meegan said.
He continued: “Thinner mill liners result in a larger volume inside the
mill. This means you can have a higher charge level. Using composite
liners also cuts the weight of the liners to about 50% of standard steel
cast liners, making it possible to work with a higher ball charge level
without increasing the total weight of the mill. Both of these benefits
result in a higher throughput.”
Yet these higher throughputs need to be achieved over long periods of
time, meaning the liners need to be wear and tear resistant and easy, fast
and safe to replace.
The mill liner handler machines, designed to cantilever inside of a mill
chamber during a liner change-out, have limitations based on the weight
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68 International Mining | APRIL 2019
AEGIS, iRing said, automatically generates all
the drill holes required for a stope according to
collar and toe spacing, and including burden. The
user defines the existing voids, the geological
contacts and optional stope design. AEGIS has
been built using its own 3D graphics engine and
can process rings automatically, semi-
automatically as well as manually, according to
the company.
For The Crush It! Challenge, and Paradigm
Shifters competition submission, iRing is working
on extending its Break Analyzer model to allow
for fragmentation analysis, according to Williams.
The Break Analyzer uses unit charges and stress
reflection methodology, in conjunction with
electronic detonators, to design ring patterns
that can “transform underground blasting
operations into primary crushing operations”,
according to iRing.
It was developed through “extensive field
of the liner components to be manipulated in place, according to
FLSmidth. Yet, due to the reduction in weight, this is no longer the
limiting factor. Instead, the limiting factor is the size of the opening into
the mill, the company said.
FLSmidth offers a variety of different mill liners as each liner needs to
fit the specific needs of the processing plant.
Meegan said: “To achieve the desired production plans, the operation
and metallurgical managers have to consider a long sequence of
equipment with a variable feed of ore hardness and ore size. It is a
complicated system that has to be controlled in a professional way, and
the managers always have a good picture of the plant in terms of
capacity, bottlenecks, restrictions, problems and opportunities.
“Now, what usually happens is that if a plant is designed for 100,000
t/d of ore, after the ramp up period, there is always a requirement to
increase the throughput with the existing equipment. This is where we, as
mill liners suppliers, can offer help. But it requires an understanding of
the specific needs of the plant as different liners suit different needs.”
Where upgrading to a composite liner is the right solution, the return
on investment is usually within half the lifetime of the wear part,
according to FLSmidth.
“Like all upgrades, there can be an increase in upfront costs, but the
total cost of ownership value is simple to calculate. This value is
manifested first by production improvements, often contributing seven
figure values to our customer’s profitability. That improvement can stand
on its own. However, with the improvements in downtime and reduction
in safety risks, the values are even greater,” he said.
The payback time for the above-mentioned plant in South America was
half the lifetime of the parts, and the mill processed more than 8 Mt.
Another customer in North America, with a 38 ft diameter SAG mill that
made a similar change to rubber ceramic composite liners, improved the
slurry discharge by 7% and processed more than 19 Mt during a 12-month
campaign.
Meegan said he expected well-established, competent and proven cast
liners to stick around for the foreseeable future, but he anticipated mill
liner designs continuing to incorporate an increasing amount of
composites in the future.
“I think operators who aren’t considering the advantages of a mill liner
package composed of both cast and composite parts are missing out on
significant benefits,” he concluded.