IPCC
system moving crushed copper ore from
underground storage bins to the surface
processing site. Mario Dilefeld, Head of Belt
Conveyor Systems at TAKRAF outlined the project
in some detail to IM.
The system called for no redundancies, which
meant that high system availability, minimal
system wear and easy maintenance of
components were critically important. The project
scope called for removal of crushed ore from 60 m
high underground storage bins with a conveying
capacity of 11,000 t/h, transportation to the
surface with a minimum number of material
transfer points, and conveying of the ore from the
underground tunnel exit to the existing processing
plant, taking into account existing infrastructure.
In designing the system, numerous innovations
resulted in six patents being implemented for the
first time, resulting in a modern, powerful and
environmentally friendly conveyor system. Highly
efficient electric drive motors replaced diesel truck
engines and as a result, CO 2 emissions produced
by transporting the material have been reduced by
more than two thirds for the same copper
production volume.
TAKRAF employed a feeder conveyor in place of
conventional belt conveyors for controlled
material discharge. The conveyor belt has a 45
degree trough angle along the entire conveyor
route, with the only chutes being in the storage
bin discharge area. The contour of the material
Rail-Veyor as an open pit haulage
option
“I’ve always said that our system doesn’t care
what it’s hauling or where it’s working. It just
works,” Rail-Veyor Technologies Global Inc’s
Executive Chairman, Jim Fisk told IM.
When asked about open pit mining, Fisk
comments: “We’ve done several engineering
studies on installing the system in an open pit.
Many times it turns out to be the most cost
effective solution available as well as better for
the environment and the safety of the workers. I
think, early on, it was just too new of an idea.
Decision makers at the mines perceived the
technology to be too risky. However, with six
systems installed now, and one of those being a
surface application, we’ve proven the
technology works. Data from our customers
validates our ‘sticker promises’ are true.”
Fisk says larger Rail-Veyor installations can
haul up to -36 in rock and easily ramp at a 22%
incline. We could probably do a greater incline,
but since our routine maintenance is mostly
done by inspection, it’s difficult for the workers
to walk any steeper of a grade.”
In regards to in-pit crushing, Fisk says it’s not
necessarily needed for Rail-Veyor’s system
given the rock particle size it can handle but it’s
56 International Mining | MAY 2020
being conveyed is specified by
a shear gate and the flow of
discharged material is defined
by varying the conveying
speed. The elimination of the
vertical sidewalls associated
with belt conveyors means
less wear and thus reduced
maintenance costs, combined
with energy savings of around
25%.
Two conventional trough
conveyors connect the
material discharge of the
feeder conveyors with the
loading point of the inclined conveyor, around 900
m away. The tunnel extends some 6,400 m to the
surface and the inclined conveyors overcome a
difference in elevation of 950 m.
As each underground transfer point along the
tunnel requires an underground chamber with
considerable infrastructure, the number of transfer
points was minimised by using an inclined
conveyor section with just two conveyors. This
was made possible by newly developed
components that redefine the performance limits
of belt conveyor technology.
St 10,000 quality conveyor belts from ContiTech
were used for the first time. Operating belt safety
ratings of S = 5.0 required belt connections with a
reference fatigue strength of over 50%. Once
probably a good idea for the mine.
“Anytime you can do something to the rock in
order to lessen the number of times it has to be
handled, it’s a good thing. If you can grade the
ore before moving it, you can decide then and
there where you want to haul it. If you know it’s
waste rock, why take it to the mill? We can move
A Rail-Veyor system moves pet coke from one of
several stockpiles on the surface to a barge at
the end of a pier. The system goes under a
public roadway through a standard box culvert.
Once one stockpile is removed, the system can
be moved to work on the next stockpile
Part of the OLC section of the ore transportation
system supplied by Tenova TAKRAF at Codelco's
Chuquicamata Underground project
again, new dimensions were achieved - this time
in terms of installed drive power - with 10,000 kW
of installed drive power per drive pulley and
20,000 kW per conveyor.
In cooperation with the drive motor
manufacturer, ABB, Tenova TAKRAF engineers
developed a drivetrain consisting of a 5,000 kW
synchronous motor, membrane coupling to
connect the pulley shaft and rotor shaft and drive
pulley .
Maintenance of the air gap between the rotor
and stator is a crucial requirement for the
operation of the motors, with the 14 mm air gap
that to get it out of your way and take the ore
straight to where it will be processed. We can
snake up and out of the pit with the least
amount of effort. Steel wheels on steel rails is
one of the most efficient ways of moving stuff.”
What also makes Rail-Veyor especially
intriguing is its quality of being autonomous.
Fisk adds: "The 'operator' can have another job,
like running the crusher, and monitor the
system with a tablet and an HMI which runs off
software specifically programmed for each
installation. When one area of the pit is
exhausted, the system can be picked up and
moved. Once the software is re-programmed,
it’s good to go."
Because of worldwide COVID-19 related travel
restrictions, Rail-Veyor’s engineering team is
working hard to be able to commission its latest
system remotely. “When we finish this project, it
will be a game changer. We will be able to
commission, and thus service the software,
from anywhere in the world…including a home
office,” says Fisk.
He concludes, “We are in trying times now.
Although I’ve never had to live through
something so disruptive, I do know it’s at these
times we reach for newer ideas to push us
forward and make our world better.”