NORDIC SUPPLIERS
tailings disposal area, helping to extend its
lifespan. The system has also enabled a 10-20%
reduction in flocculant costs,” Courtenay said.
He provided IM with further insight into the
development that went into this new technology.
“The Outotec 2nd Generation Paste Thickener
is the culmination of development work around
our paste thickener technology during the past
few years,” he told IM. “The features are
installed on a number of thickeners in the
industry and have proven to perform well.”
The vertical load monitoring and smart rakelift
feature – which makes the thickener one of the
only systems in the world able to detect early
formation of rotating beds – has been tested on
copper tailings applications in Chile with positive
results, according to Courtenay. Meanwhile, as
mentioned above, the static pickets and ACT
Thickener Optimizer control system have been
proven at Siilinjärvid.
“With these features installed on these paste
thickeners, we have witnessed a change in the
overall performance of the thickener, with steady
solids inventory maintained inside the thickener
tank, producing a consistent underflow density
near the maximum value,” he said.
The company combined several innovative
design tools in the development of this thickener
technology, according to Courtenay.
“The Finite Element Analysis design tool is
something we have used for years to design our
steel structures, but we have now started to use
Discrete Element Modelling to also estimate the
movement of solid particles inside the thickener
tank and examine areas of relative shear. We can
then use this information to optimise the design
of rake mechanism for lower drag and less
propensity to create rotating bed of solids.”
He added: “Computational Fluid Dynamics is
used in the design of our patented vane feedwell,
to determine shear rate and solids concentration
distribution across the feedwell.”
Courtenay concluded: “The features of the 2nd
generation Paste Thickener are suitable to all
high-density thickeners but are most relevant to
larger-diameter minerals tailings applications, or
smaller-size thickeners with highly viscous material.
“The key advantage of employing these
combined features is to firstly prevent the build-
up of the rotating solids bed, and, secondly, to
manage the additional vertical load. Without
these features being employed on high-viscosity
applications, there is a risk of bogging the rakes
and limiting the thickener throughput.”
The Nordic electric charge
As mentioned earlier, Epiroc is also working
alongside LKAB, ABB, Combitech and the Volvo
group, on the SUM project, which, as one of its
sub-projects, is looking to electrify the
underground mining environment.
30 International Mining | JUNE 2019
Epiroc has competition in this field. Sandvik
has, this year, acquired Artisan Vehicles to
enhance its own offering and, at the recent
Bauma event, in Munich, Normet released its
own battery-electric product line, SmartDrive.
In development since 2015, Normet’s new
battery-operated platform has started with the
launch of the SPRAYMEC 8100 VC SD, which
provides efficient concrete spraying from one set-
up in tunnels of up to 10.3 m in height and 16 m
in width. The maximum vertical spraying reach is
14 m, but the compact design enables the mobile
sprayer to perform in tunnels with cross-sections
from 15 – 140 m 2 , according to the company.
The SPRAYMEC 8100 VC SD features the latest
state-of-the-art control system for the spraying
process, the NorSmart 3, which provides
efficient, productive and high-quality concrete
spraying, according to Normet, thanks to
functions like:
n Low-pulsation concrete spraying and
pumping;
n Accurate and reliable accelerator dosing
(accelerator dosing integrated into concrete
output);
n Accurate and fast spray boom and nozzle
movements and positioning;
n Real-time control and diagnostics of the
spraying process, including optional kit for
accelerator, concrete and ambient temperature
control;
n Logging of all spraying process-related data
and USB data transfer;
n Comprehensive vehicle fault diagnostics, and;
n Optional SmartSpray semi-automatic concrete
spray boom control.
One of these machines was on display at
Bauma and Normet said much of the testing of
these SmartDrive machines took place at First
Quantum Minerals’ Pyhäsalmi base metals mine.
Normet said the machines had been
specifically designed for harsh environments and
that the emission-free, electric motors provided
instant torque and safe operation in all underground
situations – downhill, level or uphill tramming.
“No hot gases are exhausted and that is
influencing the general design for ventilation of
the mine or the tunnel, resulting in much lower
operating costs for the ventilation,” Normet said.
The whole driveline has been optimised, with
all low-efficiency parts like the gearbox, dropbox
and shafts eliminated, while the hydraulic circuit,
with all rotating parts, has been reduced.
Normet said the optimised tuning of the
electric machine´s control system reduces the
need to use the service brake, with much of the
braking force provided by the electric motors.
This braking energy is also fed back into the
battery, meaning the battery can be charged
during downhill operation.
On top of this, the machine has four-wheel
drive – a feature that keeps the brake engaged
when on hills – and three selectable speed
ranges.
“With all these optimised features, the new
generation of Normet mining and tunnelling
equipment is more sustainable; less
maintenance and service are needed; and much
more economical than other engine versions,”
Normet said.
Normet states that the lithium-ion (Li-Ion)
batteries it is using for the SmartDrive platform
have a very long lifetime and a fast-charging
capability.
Technology Director, Samu Kukkonen, was
able to elaborate on this. “We are using
industrial grade Li-Ion batteries,” he told IM.
“One has to recognise that Li-Ion is an umbrella
term. Under the Li-Ion family, there are multiple
different chemistries, some of which are better
suited to certain applications than others. In cell
phones, for example, a chemistry of choice is of
the highest energy density but compromising
usable lifetime and thermal stability.”
He said the chemistry for Normet’s industrial
Li-Ion batteries had been selected from a
“completely different end of the available
chemistries spectrum”.
“The best traits of the chemistry we are using
are of exceptional safety, super-fast-charging
capability and very long lifetime with the
expense of lower energy density.”
Normet says the onboard charging system the
SmartDrive machines are equipped with allows
the batteries to go from 0% to 80% charge in
two-and-a-half hours. Kukkonen was adamant
that this capability did not come to the detriment
of battery life.
“One of the benefits of this chemistry
selection is that what people typically call fast-
charging is not even close to what this type of a
battery can actually achieve,” he said. “Hence,
there is not much of an effect on the lifetime
even in repeated fast-charging situations.”
On top of this, the battery on the machines is
split into modules meaning, in the case of a
malfunction, the module will be isolated and the
rest of the battery will continue operating. The
machines are also fitted with two electric motors
for extra redundancy.
The big drive
Hägglunds is a name known globally for drive
technology, an opinion backed up by its most
recent contract award.
Its parent company, Germany’s Bosch Rexroth,
was selected by thyssenkrupp Industrial
Solutions Australia, in April, as the supplier of
the drive system for the largest-ever rail-
mounted bucket wheel reclaimer at BHP’s South
Flank iron ore mine in Western Australia.
Bosch Rexroth will deliver the bucket wheel