VENTILATION
battery machineries. This project is a work package
of the larger project Sustainable Intelligent Mining
Systems (SIMS), which can be seen in
http://www.simsmining.eu/ It is funded by the EU.
Loading and hauling BEVs still have to prove
themselves, not least in battery charge life and
time to recharge.
Lets take a simplified truck example of a mine
that is 500 m below surface with a 1:7 ramp,
that’s a 3.5 km one-way haul. Typical up ramp
speed is around 10 km/h and down ramp a bit
faster (depends on quality of road surface and
how tight the bends are, etc).
Allowing 5 mins to dump on surface and 10
mins to move off ramp and be loaded
underground, that means a cycle time for the
truck of around 1 hour which is fairly typical for
moderate depth operations.
If the truck is going to lose 10 mins each cycle
to swap batteries out, then that is a fairly
significant productivity loss, especially if carrying
capacity drops to 40 t from 60 t.
And if the mine is 1,000 m below surface, then
the cycle time is that much longer and it is a
struggle to see this working if the truck can’t get
at least one reliable cycle before a battery swap
or recharge.
Nevertheless, BEV development and adoption is
moving surprisingly fast, involving huge
investments by the equipment manufacturers. And
of course there are smaller or boutique players.
Sandvik has committed to a trolley assist 40 t
truck system in 2020. Artisan is also talking
about trolley assist trucks. Epiroc is working on
something also.
As for the LHDs 14 t will be available too, but
in late 2019 from CAT and Epiroc. Artisan has
sooner if it has someone to purchase the A16 –
16t LHD. Komatsu is working on an 18 t LHD.
Artisan had developed a 10 minute swap battery.
If one can get the battery to charge in 10-20
minutes and not have to remove it then that
leads to an ergonomic break in work. We need to
design mines around the capability of the
machines until the density catches up so that
BEVs are like diesel and will last the shift.
There is no problem, for example, about the
LHD mucking a 5 by 5 m down-ramp 4 m long
back to a remuck 150 m from the face. All
simulations and existing experience tells us this
is possible, so mucking a blasthole stope will not
be a problem with a small break to change or
swap once during the shift.
Leading underground mining contractor
Byrnecut Australia is trialling an underground
diesel electric hybrid production loader at OZ
Minerals’ Prominent Hill copper-gold mine. The
trial is to test production efficiencies, diesel
savings and overall costs associated with this
equipment. The machine is one of two Joy 22HD
hybrid LHDs supplied by Komatsu Mining and
uses the Switched Reluctance (SR) drive to
capture and reuse braking energy while also
equipped with KESS (Kinetic Energy Storage
System).
The 22HD also has a simple control suite
allowing the operator to concentrate on
maximising productivity. Automated control
functions allow operator to perform complex
operations at a button press while its “heavy-
duty design means less failures and more CAPEX additions:
n Mobile equipment premium C$21 million
(current assumption 140% of diesel fleet)
n Charging Infrastructure C$5 million?
TOTAL C$26 MILLION
Estimated OPEX savings:
n Fan & refrigeration power cost C$7.3 million/y
n Natural gas cost C$0.3 million/y
n Operating/maintenance cost C$0.3 million/y
TOTAL C$7.9 MILLION/Y
uptime.” The bucket design allows easy filling
and low wear and a central auto lubrication
system minimises scheduled service activity and
protects critical structural linkages and joints.
The hydraulic system with piston pumps mean
cooler operation and longer life.
At Prominent Hill underground, the operations
delivered 680,000 t of ore in Q1 2018 at 1.81%
Cu, representing consistent quarter on quarter
production. The third decline construction has
progressed, with final portal position selection
complete and breakthrough was expected in Q2.
The fourth haulage decline into the lower open pit
will commence in Q2 and completion is expected
in Q3. Procurement activity for the crusher feed
and underground ore rehandle contract is
underway with contract execution expected in Q2.
The combination of new access declines into the
underground and utilisation of the rehandle fleet
will lift underground ore production in H2 to
facilitate full year guidance of 2.8-3.1 Mt.
In its 2016 study for Glencore’s Onaping Depth
project, as shown in the diagram, Hatch noted:
Estimated CAPEX savings:
n Vent & cooling infrastructure C$24 million
n Shaft size C$5 million
n Drift size C$12 million
TOTAL C$41 million MacLean Engineering, another BEV leader,
notes the following reasons for the adoption of
battery power underground now:
n Ventilation can represent over 50% of a mine’s
power requirements/costs…as mines go
deeper, this cost pressure increases
n Removing diesel Fine Particulate Matter from
the underground mining environment (known
carcinogen - World Health
Organisation)…protecting worker health,
mitigating class action risk
n Advances in battery technology (battery
chemistry and chargers), commercial availability.
MacLean Engineering’s ventilation cost savings
modelling (cost savings of EV units compared to
diesel units) used the following input parameters:
n Ventilation requirement (f 3 /min per hp)
n Annual ventilation cost per f 3 /min
n Air heating/cooling cost per f 3 /min
n Ventilation for EV units (f 3 /min per hp)
The resulting calculated utility vehicle
ventilation savings were
1. Scissor Bolter C$89,100
2. Scissor Lift C$89,100
3. Cassette Truck C$147,400
4. Cassette Truck C$147,400
5. Boom Truck C$147,400
Total annual savings C$620,400 IM
JULY 2018 | International Mining 47